disease of field and horticultural crops and their management-II
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About This Presentation
disease of field and horticultural crops and their management-II notes
bsc agriculture 6 semester notes
APP5321 notes
3 yr 2nd sem notes agriculture
ishan dewangan
Theory
Symptoms, etiology, disease cycle and management of following diseases:
Field Crops:
Wheat: rusts, loose smut, karnal bunt, ...
Slide Content
Page | 1
SUNFLOWER
SCLEROTINIA STEM ROT
Sclerotinia sclerotiorum
Symptom:
Three stages –
• Sclerotinia root rot, Basal stalk rot, and wilt
• Sclerotinia stem rot
• Sclerotinia head rot and midstalk rot
Sclerotinia root rot, Basal stalk rot, and wilt
• The first above-ground symptom of Sclerotinia root rot, Basal stalk rot, and wilt is sudden wilting of the
sunflower plants before or during flowering with wilted plants often being found in clumps.
• Over time, tan-colored, water soaked lesions develop at the base of the plants, which can girdle the stem.
• As the disease continues to develop on the plant, the stem appears bleached and shredded, and has a
decayed pith.
• The infected plants can easily lodge in the field during high winds.
• Black sclerotia (1 to 2 mm in diameter) can be found inside, and sometimes on the outside, of the stem.
Sclerotinia stem rot
• Symptoms can appear any time after the seedling growth stages of sunflower but the disease occurs mostly
at mid- to late- growing season of the crop.
• Initially, small, water- soaked lesions develop on the plants near the soil line.
• As the disease progresses, secondary symptoms can appear on the plant, which includes wilting, bleaching
and shredding of the stem.
• The pith of the stem beneath the lesions often contains mycelial growth and abundant black sclerotia.
• In addition, sclerotia are seen on the outside of the stem.
• As the disease progresses, the stem can break and shred with only the vascular elements visible.
Sclerotinia head rot and midstalk rot
• This disease may be common before or after flowering.
• Symptoms of Sclerotinia head rot include dark-colored, water-soaked lesions on the backside of the
sunflower heads or the presence of white mycelial growth, which covers the developing seeds in the head.
• Later, large sclerotia develops in head and around the seed
• As the disease progresses, the sunflower head disintegrates and shreds, leaving behind large sclerotia (12 cm
or greater in diameter).
• Symptoms of Sclerotinia head rot can be confused with Rhizopus head rot. However, sunflower heads
affected by Rhizopus head rot will exhibit gray-colored, threadlike mycelial strands with no sclerotia.
Etiology:
• Sub-Division – Ascomycotina
• Mycelium – Septate, branched and hyaline
• Colony – White
• Sclerotia – Black, sclerotia give rise to a fruiting body which produces Ascospore
• Sexual fruiting body – Apothecia
Favourable condition:
• High humidity (90-95%)
SUNFLOWER
SCLEROTINIA STEM ROT
Sclerotinia sclerotiorum
Symptom:
Three stages –
• Sclerotinia root rot, Basal stalk rot, and wilt
• Sclerotinia stem rot
• Sclerotinia head rot and midstalk rot
Sclerotinia root rot, Basal stalk rot, and wilt
• The first above-ground symptom of Sclerotinia root rot, Basal stalk rot, and wilt is sudden wilting of the
sunflower plants before or during flowering with wilted plants often being found in clumps.
• Over time, tan-colored, water soaked lesions develop at the base of the plants, which can girdle the stem.
• As the disease continues to develop on the plant, the stem appears bleached and shredded, and has a
decayed pith.
• The infected plants can easily lodge in the field during high winds.
• Black sclerotia (1 to 2 mm in diameter) can be found inside, and sometimes on the outside, of the stem.
Sclerotinia stem rot
• Symptoms can appear any time after the seedling growth stages of sunflower but the disease occurs mostly
at mid- to late- growing season of the crop.
• Initially, small, water- soaked lesions develop on the plants near the soil line.
• As the disease progresses, secondary symptoms can appear on the plant, which includes wilting, bleaching
and shredding of the stem.
• The pith of the stem beneath the lesions often contains mycelial growth and abundant black sclerotia.
• In addition, sclerotia are seen on the outside of the stem.
• As the disease progresses, the stem can break and shred with only the vascular elements visible.
Sclerotinia head rot and midstalk rot
• This disease may be common before or after flowering.
• Symptoms of Sclerotinia head rot include dark-colored, water-soaked lesions on the backside of the
sunflower heads or the presence of white mycelial growth, which covers the developing seeds in the head.
• Later, large sclerotia develops in head and around the seed
• As the disease progresses, the sunflower head disintegrates and shreds, leaving behind large sclerotia (12 cm
or greater in diameter).
• Symptoms of Sclerotinia head rot can be confused with Rhizopus head rot. However, sunflower heads
affected by Rhizopus head rot will exhibit gray-colored, threadlike mycelial strands with no sclerotia.
Etiology:
• Sub-Division – Ascomycotina
• Mycelium – Septate, branched and hyaline
• Colony – White
• Sclerotia – Black, sclerotia give rise to a fruiting body which produces Ascospore
• Sexual fruiting body – Apothecia
Favourable condition:
• High humidity (90-95%)
Page | 2
• Average temperature (18-25 ℃)
• Monocropping
• Dense cropping
Management:
• Deep summer ploughing.
• Use Disease free seeds/resistant variety.
• 4-5 years crop rotation with non host plants (Wheat, Sorghum, Maize)
• Field sanitation.
• Avoid dense planting
• Chemical – Tabuconazole or azoxystrobin
• Trichoderma
• Apply Neem cake + Organic Manure
• There should be proper drainage in fields.
• Excessive rates of nitrogen in sunflower fields should be avoided as excess nitrogen can promote dense
canopies and provide the microclimate for disease development.
Disease cycle:
ALTERNARIA BLIGHT
Alternaria helianthin
Symptom:
• circular, dark brown to black lesions with concentric rings appears mostly on lower leaves
• Lesions will eventually enlarge in size and coalesce causing blighting of leaves.
• Some lesions can be identified by distinct yellow halos, particularly on young plants.
• If the disease is severe, plants may be defoliated prematurely and die or lodge.
• Average temperature (18-25 ℃)
• Monocropping
• Dense cropping
Management:
• Deep summer ploughing.
• Use Disease free seeds/resistant variety.
• 4-5 years crop rotation with non host plants (Wheat, Sorghum, Maize)
• Field sanitation.
• Avoid dense planting
• Chemical – Tabuconazole or azoxystrobin
• Trichoderma
• Apply Neem cake + Organic Manure
• There should be proper drainage in fields.
• Excessive rates of nitrogen in sunflower fields should be avoided as excess nitrogen can promote dense
canopies and provide the microclimate for disease development.
Disease cycle:
ALTERNARIA BLIGHT
Alternaria helianthin
Symptom:
• circular, dark brown to black lesions with concentric rings appears mostly on lower leaves
• Lesions will eventually enlarge in size and coalesce causing blighting of leaves.
• Some lesions can be identified by distinct yellow halos, particularly on young plants.
• If the disease is severe, plants may be defoliated prematurely and die or lodge.
Page | 3
Etiology:
• Mycelium – Septate, Branched and Dark
• Conidia – Muriform (longitudinal and transverse septation), dark, formed in chain
• Conidiophore – short, dark colored, simple, septate
Favourable condition:
• Moist weather (more than 70% relative humidity)
• Warm weather (20-25 °C )
• Intermittent rains favours disease development
• Late sown crops are highly susceptible.
Management:
• Deep summer ploughing.
• Maintain proper spacing.
• Clean cultivation and field sanitation.
• Application of well rotten manure.
• Practising crop rotation.
• Planting early.
• Remove and destroy diseased plants.
• Application of Trichoderma.
• Seed treatment with thiram or carbendazim @2G/kg.
• Spray mancozeb @0.2%
Disease cycle:
MUSTARD
ALTERNARIA BLIGHT
Alternaria brassicae
Symptom:
• The disease attacks on the lower leaves as small circular brown necrotic spots which slowly increase in size.
Etiology:
• Mycelium – Septate, Branched and Dark
• Conidia – Muriform (longitudinal and transverse septation), dark, formed in chain
• Conidiophore – short, dark colored, simple, septate
Favourable condition:
• Moist weather (more than 70% relative humidity)
• Warm weather (20-25 °C )
• Intermittent rains favours disease development
• Late sown crops are highly susceptible.
Management:
• Deep summer ploughing.
• Maintain proper spacing.
• Clean cultivation and field sanitation.
• Application of well rotten manure.
• Practising crop rotation.
• Planting early.
• Remove and destroy diseased plants.
• Application of Trichoderma.
• Seed treatment with thiram or carbendazim @2G/kg.
• Spray mancozeb @0.2%
Disease cycle:
MUSTARD
ALTERNARIA BLIGHT
Alternaria brassicae
Symptom:
• The disease attacks on the lower leaves as small circular brown necrotic spots which slowly increase in size.
Page | 4
• Many concentric spots coalesce to cover large patches showing blightening and defoliation in severe cases.
• Circular to linear, dark brown lesions also develop on stems and pods, which are elongated at later stage.
• Infected pods produce small, discolored and shriveled seeds.
• During dry season, infected portion of leaf fall off.
Etiology:
• Mycelium – Septate, Branched and Dark
• Conidia – Muriform (longitudinal and transverse septation), dark, formed in chain
• Conidiophore – short, dark coloured, simple, septate
Favourable condition:
• Moist weather (more than 70% relative humidity)
• Warm weather (20-25 °C )
• Intermittent rains favours disease development
Management:
• Deep summer ploughing.
• Maintain proper spacing.
• Clean cultivation and field sanitation.
• Application of well rotten manure.
• Practising crop rotation.
• Planting early.
• Remove and destroy diseased plants.
• Application of Trichoderma.
• Seed treatment with thiram or carbendazim @2G/kg.
• Spray mancozeb @0.2%
Disease cycle:
WHITE RUST
Albugo candida
Symptom:
• Many concentric spots coalesce to cover large patches showing blightening and defoliation in severe cases.
• Circular to linear, dark brown lesions also develop on stems and pods, which are elongated at later stage.
• Infected pods produce small, discolored and shriveled seeds.
• During dry season, infected portion of leaf fall off.
Etiology:
• Mycelium – Septate, Branched and Dark
• Conidia – Muriform (longitudinal and transverse septation), dark, formed in chain
• Conidiophore – short, dark coloured, simple, septate
Favourable condition:
• Moist weather (more than 70% relative humidity)
• Warm weather (20-25 °C )
• Intermittent rains favours disease development
Management:
• Deep summer ploughing.
• Maintain proper spacing.
• Clean cultivation and field sanitation.
• Application of well rotten manure.
• Practising crop rotation.
• Planting early.
• Remove and destroy diseased plants.
• Application of Trichoderma.
• Seed treatment with thiram or carbendazim @2G/kg.
• Spray mancozeb @0.2%
Disease cycle:
WHITE RUST
Albugo candida
Symptom:
Page | 5
• Both local and systemic infections are observed.
• In case of local infection, white creamy yellow raised pustules appear on the lower side of leaves which later
coalesce to form patches.
• In systemic infection and during humid weather, swelling and distortion of the stem and floral parts due to
hypertrophy and hyperplasia occurs and develop “stag head” structure.
Etiology:
• Sub-Division – Mastigomycotina
• Family – Albuginaceae
• Mycelium - non-septate and hyaline
• Sporangiophores emerge through the stomata
• They are unbranched and bear sporangia in chain
• Sporangia - hyaline, round or oval
• The sporangia germinate to produce abundant zoospores.
• The fungus also produces oospores
Favourable conditions:
• T = 15-20°C
• >90% RH
• Cloudy days
• Intermittent rains
• Dense cropping
• Poor drainage of soil
Management:
• Sanitation
• Proper drainage
• Selection of healthy seeds
• Foliar application of Ridomil (0.01%)
• Soil application of Trichoderma bioformulation @ 25kg/ha
• 2-3 times deep summer ploughing during hot summer days followed by irrigation
• Crop rotation with non host
• Do not allow field to field irrigation specially from diseased fields to healthy fields.
Etiology:
• Both local and systemic infections are observed.
• In case of local infection, white creamy yellow raised pustules appear on the lower side of leaves which later
coalesce to form patches.
• In systemic infection and during humid weather, swelling and distortion of the stem and floral parts due to
hypertrophy and hyperplasia occurs and develop “stag head” structure.
Etiology:
• Sub-Division – Mastigomycotina
• Family – Albuginaceae
• Mycelium - non-septate and hyaline
• Sporangiophores emerge through the stomata
• They are unbranched and bear sporangia in chain
• Sporangia - hyaline, round or oval
• The sporangia germinate to produce abundant zoospores.
• The fungus also produces oospores
Favourable conditions:
• T = 15-20°C
• >90% RH
• Cloudy days
• Intermittent rains
• Dense cropping
• Poor drainage of soil
Management:
• Sanitation
• Proper drainage
• Selection of healthy seeds
• Foliar application of Ridomil (0.01%)
• Soil application of Trichoderma bioformulation @ 25kg/ha
• 2-3 times deep summer ploughing during hot summer days followed by irrigation
• Crop rotation with non host
• Do not allow field to field irrigation specially from diseased fields to healthy fields.
Etiology:
Page | 6
DOWNY MILDEW
Peronospora brassicae
Hyaloperonospora parasitica
Symptom:
• Yellow lesions appears on the upper surface of the leaves
• Corresponding lower side of the leaves white-grey coloured fungal growth can be seen
• Deformation of stem occurs
• Infected plants produce sterile flowers.
Etiology:
• Sub-Division – Mastigomycotina
• Family – Perenosporaceae
• Mycelium : Hyaline, branched, coenocytic, intercellular with finger shaped haustoria
• Sporangiophores : dichotomous branching @ acute angles to the axis
• Sporangia : Hyaline, single celled, lemon shaped, don’t produce zoospore after germination
• Oospore : Simple, double thick walled, spherical
Favourable conditions:
• Relative humidity is above 80%
• Temperature is 18 and 23 ℃
• More conidia production in 13-18℃
Management:
• Sanitation
• Crop rotation
• Summer deep ploughing
• Eradication of weed host
• Chemical - Fosetly aluminium 0.2% or Metalaxyl 0.2% or Copper oxychloride are effective
Disease cycle:
• Survival – Oospore in Soil + Plant Debris
• PI - The primary infection of the disease is initiated from the oospores.
• Secondary spread - sporangia, which are formed on the new shoots.
DOWNY MILDEW
Peronospora brassicae
Hyaloperonospora parasitica
Symptom:
• Yellow lesions appears on the upper surface of the leaves
• Corresponding lower side of the leaves white-grey coloured fungal growth can be seen
• Deformation of stem occurs
• Infected plants produce sterile flowers.
Etiology:
• Sub-Division – Mastigomycotina
• Family – Perenosporaceae
• Mycelium : Hyaline, branched, coenocytic, intercellular with finger shaped haustoria
• Sporangiophores : dichotomous branching @ acute angles to the axis
• Sporangia : Hyaline, single celled, lemon shaped, don’t produce zoospore after germination
• Oospore : Simple, double thick walled, spherical
Favourable conditions:
• Relative humidity is above 80%
• Temperature is 18 and 23 ℃
• More conidia production in 13-18℃
Management:
• Sanitation
• Crop rotation
• Summer deep ploughing
• Eradication of weed host
• Chemical - Fosetly aluminium 0.2% or Metalaxyl 0.2% or Copper oxychloride are effective
Disease cycle:
• Survival – Oospore in Soil + Plant Debris
• PI - The primary infection of the disease is initiated from the oospores.
• Secondary spread - sporangia, which are formed on the new shoots.
Page | 7
SCLEROTINIA STEM ROT
Sclerotinia sclerotiorum
Symptom:
• Elongated water soaked lesions appear on stem near to the crown region, covered with cottony mycelial
growth later on.
• Plant looks like whitish from distance at internodes or base.
• Premature shredding of stem, wilting and drying.
• Brown to black sclerotial bodies may also be seen in the later stage on the infected plant parts.
Etiology:
• Sub-Division – Ascomycotina
• Mycelium – Septate, branched and hyaline
• Colony – White
• Sclerotia – Black, sclerotia give rise to a fruiting body which produces Ascospore
• Sexual fruiting body – Apothecia
Favourable conditions:
• High humidity (90-95%)
• Average temperature (18-25 ℃)
• Monocropping
• Dense cropping
Management:
• Deep summer ploughing.
• Use Disease free seeds/resistant variety.
• 4-5 years crop rotation with non host plants.
• Field sanitation.
• Avoid dense planting.
• Chemical
• Trichoderma
• Apply Neem cake + Organic Manure
• There should be proper drainage in fields
Disease cycle:
SCLEROTINIA STEM ROT
Sclerotinia sclerotiorum
Symptom:
• Elongated water soaked lesions appear on stem near to the crown region, covered with cottony mycelial
growth later on.
• Plant looks like whitish from distance at internodes or base.
• Premature shredding of stem, wilting and drying.
• Brown to black sclerotial bodies may also be seen in the later stage on the infected plant parts.
Etiology:
• Sub-Division – Ascomycotina
• Mycelium – Septate, branched and hyaline
• Colony – White
• Sclerotia – Black, sclerotia give rise to a fruiting body which produces Ascospore
• Sexual fruiting body – Apothecia
Favourable conditions:
• High humidity (90-95%)
• Average temperature (18-25 ℃)
• Monocropping
• Dense cropping
Management:
• Deep summer ploughing.
• Use Disease free seeds/resistant variety.
• 4-5 years crop rotation with non host plants.
• Field sanitation.
• Avoid dense planting.
• Chemical
• Trichoderma
• Apply Neem cake + Organic Manure
• There should be proper drainage in fields
Disease cycle:
Page | 8
GRAM
WILT
Fusarium oxysporum f.sp. ciceris
Symptom:
• Drooping of upper leaves
• Yellowing of lower leaves
• Entire yellowing of the foliage
• Later, whole plant die.
• Generally appear in patches in field
• The vascular system of the plant is discolored, particularly in the lower stem and roots.
Etiology:
• Mycelium :- Septate, branched, light pink
• Conidia :-
Macro conidia - boat shaped, hyaline, long septate, pointed at tip
Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium
• Chlamydospore:- spherical, thick walled
Favourable conditions:
• Relatively high soil moisture and soil temperature
• Heavy rainfall, excessive and frequent irrigation
• poorly drained soil and close spacing
• high soil moisture with temp around 25-30 °C.
management:
• Field sanitation
• Remove infected plants debris.
• Apply neem cake or mustard cake to inhibit the growth of pathogen.
• Drenching with 1% Bordeaux mixture or Carbendazim 0.25% or Mancozeb may give protection.
• Seed treatment with 4g Trichoderma formulation or 2g Carbendazim per kg seed is effective.
• Apply Trichoderma mixed with organic manure
• Crop rotation with non host
• Flooding of filed for 10 days if possible
• Apply organic manure as much as possible
Disease cycle:
• Pathogen survives in soil and plant debris as mycelium and chlamydospores.
• PI: dormant hyphae and chlamydospores in the soil.
• SI: conidia and chlamydospores which are carried by water and farm equipment.
GRAM
WILT
Fusarium oxysporum f.sp. ciceris
Symptom:
• Drooping of upper leaves
• Yellowing of lower leaves
• Entire yellowing of the foliage
• Later, whole plant die.
• Generally appear in patches in field
• The vascular system of the plant is discolored, particularly in the lower stem and roots.
Etiology:
• Mycelium :- Septate, branched, light pink
• Conidia :-
Macro conidia - boat shaped, hyaline, long septate, pointed at tip
Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium
• Chlamydospore:- spherical, thick walled
Favourable conditions:
• Relatively high soil moisture and soil temperature
• Heavy rainfall, excessive and frequent irrigation
• poorly drained soil and close spacing
• high soil moisture with temp around 25-30 °C.
management:
• Field sanitation
• Remove infected plants debris.
• Apply neem cake or mustard cake to inhibit the growth of pathogen.
• Drenching with 1% Bordeaux mixture or Carbendazim 0.25% or Mancozeb may give protection.
• Seed treatment with 4g Trichoderma formulation or 2g Carbendazim per kg seed is effective.
• Apply Trichoderma mixed with organic manure
• Crop rotation with non host
• Flooding of filed for 10 days if possible
• Apply organic manure as much as possible
Disease cycle:
• Pathogen survives in soil and plant debris as mycelium and chlamydospores.
• PI: dormant hyphae and chlamydospores in the soil.
• SI: conidia and chlamydospores which are carried by water and farm equipment.
Page | 9
GREY MOULD
Botrytis cinerea
Symptoms:
• Lack of pod setting is the first indication.
• Under favourable conditions, foliage shows symptoms and plants often die in patches.
• Shedding of flowers and leaves, covered with spore mass can be seen.
• Lesions on stem are 10-30 mm long and girdle the stem fully.
• Tender branches break off at the point where the gray mould has caused rotting.
• Affected flowers turn in to a rotting mass.
• Lesions on the pod are water-soaked and irregular.
• On infected plants, the pods contain either small, shrivelled seeds or no seeds at all.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia (Globose)
• Conidiophore – Highly branched
• Colony color – Dark
• Produce sclerotia
Favourable conditions:
• Gray mould favours moist, humid, and warm environmental conditions between 18 -24℃ (65-75℉).
• Temperature, relative humidity, and wetness duration produce a conducive environment that is favourable
for inoculation of mycelium or conidia.
Management:
• Intercrop with linseed.
• Avoid excessive irrigation.
• Deep summer ploughing
• Reduce plant density and increase in air passage between the plants.
• Seed treatment with Carbendazim + Thiram (1:1) @ 3g/kg of seed is recommended
• Spray the crop with Captan 5 - 6 kg/ha at 15 days interval, Carbendazim @ 1.5g/lit of water, Mancozeb @3
g/lit of water
Disease cycle:
GREY MOULD
Botrytis cinerea
Symptoms:
• Lack of pod setting is the first indication.
• Under favourable conditions, foliage shows symptoms and plants often die in patches.
• Shedding of flowers and leaves, covered with spore mass can be seen.
• Lesions on stem are 10-30 mm long and girdle the stem fully.
• Tender branches break off at the point where the gray mould has caused rotting.
• Affected flowers turn in to a rotting mass.
• Lesions on the pod are water-soaked and irregular.
• On infected plants, the pods contain either small, shrivelled seeds or no seeds at all.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia (Globose)
• Conidiophore – Highly branched
• Colony color – Dark
• Produce sclerotia
Favourable conditions:
• Gray mould favours moist, humid, and warm environmental conditions between 18 -24℃ (65-75℉).
• Temperature, relative humidity, and wetness duration produce a conducive environment that is favourable
for inoculation of mycelium or conidia.
Management:
• Intercrop with linseed.
• Avoid excessive irrigation.
• Deep summer ploughing
• Reduce plant density and increase in air passage between the plants.
• Seed treatment with Carbendazim + Thiram (1:1) @ 3g/kg of seed is recommended
• Spray the crop with Captan 5 - 6 kg/ha at 15 days interval, Carbendazim @ 1.5g/lit of water, Mancozeb @3
g/lit of water
Disease cycle:
Page | 10
ASCOCHYTA BLIGHT
Ascochyta rabiei
Symptom:
• The initial symptom of the disease appears near the tip of young shoot and top most leaves.
• The fungus attacks all above ground parts like leaves, stems and pods at any stage of the plant growth.
• But plants are most susceptible to disease during flowering.
• Pale green - yellow, circular, depressed lesions appeared on leaves and pods.
• Elongated lesions on petioles and stem.
• Stem lesions often gridle the stem of the plant.
• Infected seed may discoloured, shrivelled and pycnidia may be present on such seeds.
• Pycnidia may be formed on these lesions usually in concentric rings.
Etiology:
• Ascochyta rabiei (exists both as and anamorph) asexual teleomorph sexual Didymella rabiei.
• Mycelium pale cream colored, Septate and Branched
• Fruiting bodies –
Asexual - pycnidia.
Sexual - Pseudothecia.
• Spores-
asexual – Conidia
Sexual – Ascospores
• The conidia are oval to oblong, one to two celled, thin walled and hyaline.
Favourable conditions:
• Temperature between 20-25°C
• Rainfall more than 350mm and high humidity favours this disease.
• Susceptible variety
Management:
• Deep summer ploughing
• Organic manure
• Application of Trichoderma & Pseudomonas fluorescence
• Disease free seeds
• Seed treatment with Fungicides (carbendazim (bavistin) @ 2g/kg of seed)
• Hot water seed treatment (52° c for 10min) to lower the infestation.
• Removal and destruction of dead plant debris.
• Follow crop rotation.
• Intercrop with wheat , barley and mustard.
• Grow resistant varieties like Pusa 408 ,Pusa 417,ICL6328
ASCOCHYTA BLIGHT
Ascochyta rabiei
Symptom:
• The initial symptom of the disease appears near the tip of young shoot and top most leaves.
• The fungus attacks all above ground parts like leaves, stems and pods at any stage of the plant growth.
• But plants are most susceptible to disease during flowering.
• Pale green - yellow, circular, depressed lesions appeared on leaves and pods.
• Elongated lesions on petioles and stem.
• Stem lesions often gridle the stem of the plant.
• Infected seed may discoloured, shrivelled and pycnidia may be present on such seeds.
• Pycnidia may be formed on these lesions usually in concentric rings.
Etiology:
• Ascochyta rabiei (exists both as and anamorph) asexual teleomorph sexual Didymella rabiei.
• Mycelium pale cream colored, Septate and Branched
• Fruiting bodies –
Asexual - pycnidia.
Sexual - Pseudothecia.
• Spores-
asexual – Conidia
Sexual – Ascospores
• The conidia are oval to oblong, one to two celled, thin walled and hyaline.
Favourable conditions:
• Temperature between 20-25°C
• Rainfall more than 350mm and high humidity favours this disease.
• Susceptible variety
Management:
• Deep summer ploughing
• Organic manure
• Application of Trichoderma & Pseudomonas fluorescence
• Disease free seeds
• Seed treatment with Fungicides (carbendazim (bavistin) @ 2g/kg of seed)
• Hot water seed treatment (52° c for 10min) to lower the infestation.
• Removal and destruction of dead plant debris.
• Follow crop rotation.
• Intercrop with wheat , barley and mustard.
• Grow resistant varieties like Pusa 408 ,Pusa 417,ICL6328
Page | 11
Disease cycle:
LENTIL
RUST
Uromyces fabae
Symptoms:
Uromyces fabae
Symptoms:
• The first symptoms appear as tiny, whitish, slightly raised spots on the upper surface of leaves.
• As they enlarge these spots turn powdery and orange or brown in colour and often surrounded by a lighter
halo.
• These pustules also appears on lower side of leaves, stems and pods.
• They may coalesce to form larger pustules.
• In severe infections leaves are shed and plants dry prematurely, the affected plant dries without forming any
seeds in pods or with small shrivelled seeds.
Etiology:
• Sub-division – Basidiomycotina
• Mycelium – Hyaline, Septate, Branched
• Aeciospore – Elliptical, Yellow in color
• Uredospore – Oval, Light brown, Spiny
• Teliospore – Oval and Thick walled
Favourable conditions:
• High humidity, cloudy or drizzly weather with temperatures 17 to 22°C favor disease development.
• The disease generally occurs during the flowering /early podding stage.
Management:
• Make sure to use healthy seeds from certified sources .
• Choose resistant varieties if available (Pant L-639)
• Plan a crop rotation with a non-host crop
• keep the fields clear of weeds and volunteer plants.
• Monitor the fields for signs of the disease.
• Spray Propiconazole, Tridemorph
• Apply organic manure to boost plant immunity
• Avoid monoculture
• Seed treatment with Thiram
Disease cycle:
Disease cycle:
LENTIL
RUST
Uromyces fabae
Symptoms:
Uromyces fabae
Symptoms:
• The first symptoms appear as tiny, whitish, slightly raised spots on the upper surface of leaves.
• As they enlarge these spots turn powdery and orange or brown in colour and often surrounded by a lighter
halo.
• These pustules also appears on lower side of leaves, stems and pods.
• They may coalesce to form larger pustules.
• In severe infections leaves are shed and plants dry prematurely, the affected plant dries without forming any
seeds in pods or with small shrivelled seeds.
Etiology:
• Sub-division – Basidiomycotina
• Mycelium – Hyaline, Septate, Branched
• Aeciospore – Elliptical, Yellow in color
• Uredospore – Oval, Light brown, Spiny
• Teliospore – Oval and Thick walled
Favourable conditions:
• High humidity, cloudy or drizzly weather with temperatures 17 to 22°C favor disease development.
• The disease generally occurs during the flowering /early podding stage.
Management:
• Make sure to use healthy seeds from certified sources .
• Choose resistant varieties if available (Pant L-639)
• Plan a crop rotation with a non-host crop
• keep the fields clear of weeds and volunteer plants.
• Monitor the fields for signs of the disease.
• Spray Propiconazole, Tridemorph
• Apply organic manure to boost plant immunity
• Avoid monoculture
• Seed treatment with Thiram
Disease cycle:
Page | 12
• Rust is an autoecious fungus, completing its life cycle on lentil.
WILT
Fusarium oxysporum f.sp. lentis
Symptoms:
• Drooping of upper leaves
• Yellowing of lower leaves
• Entire yellowing of the foliage
• Later, whole plant die.
• Generally appear in patches in field
• The vascular system of the plant is discolored, particularly in the lower stem and roots.
Etiology:
• Mycelium :- Septate, branched, light pink
• Conidia :-
Macro conidia - boat shaped, hyaline, long septate, pointed at tip
Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium
• Chlamydospore:- spherical, thick walled
Favourable conditions:
• Relatively high soil moisture and soil temperature
• Heavy rainfall, excessive and frequent irrigation
• poorly drained soil and close spacing
• high soil moisture with temp around 25-30 °C
management:
• Field sanitation
• Remove infected plants debris.
• Apply neem cake or mustard cake to inhibit the growth of pathogen.
• Drenching with 1% Bordeaux mixture or Carbendazim 0.25% or Mancozeb may give protection.
• Seed treatment with 4g Trichoderma formulation or 2g Carbendazim per kg seed is effective.
• Apply Trichoderma mixed with organic manure
• Crop rotation with non host
• Flooding of filed for 10 days if possible
• Apply organic manure as much as possible
Disease cycle:
• Pathogen survives in soil and plant debris as mycelium and chlamydospores
• PI: dormant hyphae and chlamydospores in the soil.
• Rust is an autoecious fungus, completing its life cycle on lentil.
WILT
Fusarium oxysporum f.sp. lentis
Symptoms:
• Drooping of upper leaves
• Yellowing of lower leaves
• Entire yellowing of the foliage
• Later, whole plant die.
• Generally appear in patches in field
• The vascular system of the plant is discolored, particularly in the lower stem and roots.
Etiology:
• Mycelium :- Septate, branched, light pink
• Conidia :-
Macro conidia - boat shaped, hyaline, long septate, pointed at tip
Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium
• Chlamydospore:- spherical, thick walled
Favourable conditions:
• Relatively high soil moisture and soil temperature
• Heavy rainfall, excessive and frequent irrigation
• poorly drained soil and close spacing
• high soil moisture with temp around 25-30 °C
management:
• Field sanitation
• Remove infected plants debris.
• Apply neem cake or mustard cake to inhibit the growth of pathogen.
• Drenching with 1% Bordeaux mixture or Carbendazim 0.25% or Mancozeb may give protection.
• Seed treatment with 4g Trichoderma formulation or 2g Carbendazim per kg seed is effective.
• Apply Trichoderma mixed with organic manure
• Crop rotation with non host
• Flooding of filed for 10 days if possible
• Apply organic manure as much as possible
Disease cycle:
• Pathogen survives in soil and plant debris as mycelium and chlamydospores
• PI: dormant hyphae and chlamydospores in the soil.
Page | 13
• SI: conidia and chlamydospores which are carried by water and farm equipment.
COTTON
ANTHRACNOSE
• Colletotrichum capsici
• Glomerella gossypii
Symptoms:
• The pathogen infects the seedlings and cause damping off
• Produces small reddish circular spots on the cotyledons and primary leaves.
• The lesions develop on the collar region, stem may be girdled, causing seedling to wilt and die.
• In mature plants, the fungus attacks the stem, leading to stem splitting and shredding of bark.
• The most common symptom is boll spotting.
• Small water soaked, circular, reddish brown depressed spots appear on the bolls.
• The lint is stained to yellow or brown, becomes a solid brittle mass of fiber.
• The infected bolls cease to grow and burst and dry up prematurely.
Etiology:
• Sub-Division - Deuteromycotina
• Mycelium - Septate, branched and Dark
• The mycelium of the fungus is localized in the spot.
• Asexual Spore - Conidia - hyaline, single celled and falcate in shape.
• Asexual fruiting body - Acervullus
• Acervuli with setae arise through epidermis.
• Sexual fruiting body - Perithecia - Pear shaped, In Leaf sheath
• Also produce Chlamydospore
• Colony colour – Black
Favourable condition:
• Temp-28-32 °C
• RH-95%
• High humid conditions when rain occurs after the fruits have started to ripe
• Susceptible variety.
Management:
• Deep summer ploughing
• Organic manure
• Application of Trichoderma & Pseudomonas fluorescence
• Crop rotation with non host
• SI: conidia and chlamydospores which are carried by water and farm equipment.
COTTON
ANTHRACNOSE
• Colletotrichum capsici
• Glomerella gossypii
Symptoms:
• The pathogen infects the seedlings and cause damping off
• Produces small reddish circular spots on the cotyledons and primary leaves.
• The lesions develop on the collar region, stem may be girdled, causing seedling to wilt and die.
• In mature plants, the fungus attacks the stem, leading to stem splitting and shredding of bark.
• The most common symptom is boll spotting.
• Small water soaked, circular, reddish brown depressed spots appear on the bolls.
• The lint is stained to yellow or brown, becomes a solid brittle mass of fiber.
• The infected bolls cease to grow and burst and dry up prematurely.
Etiology:
• Sub-Division - Deuteromycotina
• Mycelium - Septate, branched and Dark
• The mycelium of the fungus is localized in the spot.
• Asexual Spore - Conidia - hyaline, single celled and falcate in shape.
• Asexual fruiting body - Acervullus
• Acervuli with setae arise through epidermis.
• Sexual fruiting body - Perithecia - Pear shaped, In Leaf sheath
• Also produce Chlamydospore
• Colony colour – Black
Favourable condition:
• Temp-28-32 °C
• RH-95%
• High humid conditions when rain occurs after the fruits have started to ripe
• Susceptible variety.
Management:
• Deep summer ploughing
• Organic manure
• Application of Trichoderma & Pseudomonas fluorescence
• Crop rotation with non host
Page | 14
• Disease free seeds
• Seed treatment with Captan or Thiram 3-4g/kg
• Avoid intercropping with susceptible turmeric cultivars
• Collect and destroy all infected plant parts
• Removal and destruction of Solanaceous weed hosts and infected plant debris
• Spray three times with Captan 1.5% or [email protected]%
• just before flowering, at fruit formation stage and 15 days after second spray
disease cycle:
• Seed borne
• Secondary spread is by air borne conidia & rain
• Flies and other insects - responsible for dissemination of the spores from one plant to another.
VASCULAR WILT
Fusarium oxysporum f.sp. vasinfectum
Symptoms:
• The disease affect the crop at all stages.
• The earliest symptoms appear on the seedling in the cotyledons which turn yellow and then brown
• The base of petiole shows brown ring, followed by wilting and drying of the seedlings.
• In young and grown up plants, the first symptom is yellowing of edges of leaves and area around the veins,
i.e. discoloration starts from the margin and spreads towards the midrib.
• The leaves loose their turgidity, gradually turn brown, droop and finally drop off.
• Symptoms start from the older leaves at the base, followed by younger ones towards the top, finally
involving the branches and the whole plant.
• The vascular system of infected plants shows brown discolouration.
Etiology:
• Mycelium :- Septate, branched, light pink
• Conidia :-
Macro conidia - boat shaped, hyaline, long septate, pointed at tip
Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium Asexual fruiting body :- Sporodochia
• Chlamydospore:- spherical, thick walled
Favourable condition:
• Soil temperature of 20-30 ℃
• Hot and dry period followed by rain
• Heavy black soils with on alkaline reaction
• Increased doses of nitrogen fertilizer.
Management:
• Treat the delinted seeds with Carbendazim at 2 g/kg.
• Remove and destroy the infected plant debris after deep ploughing in summer months
• Apply heavy doses of farm yard manure or compost at 100t/ha.
• Follow crop rotation by growing paddy or Lucerne or chrysanthemum for 2-3 years.
• Avoid late season irrigation
• soil solarization effectively control wilt.
• Disease free seeds
• Seed treatment with Captan or Thiram 3-4g/kg
• Avoid intercropping with susceptible turmeric cultivars
• Collect and destroy all infected plant parts
• Removal and destruction of Solanaceous weed hosts and infected plant debris
• Spray three times with Captan 1.5% or [email protected]%
• just before flowering, at fruit formation stage and 15 days after second spray
disease cycle:
• Seed borne
• Secondary spread is by air borne conidia & rain
• Flies and other insects - responsible for dissemination of the spores from one plant to another.
VASCULAR WILT
Fusarium oxysporum f.sp. vasinfectum
Symptoms:
• The disease affect the crop at all stages.
• The earliest symptoms appear on the seedling in the cotyledons which turn yellow and then brown
• The base of petiole shows brown ring, followed by wilting and drying of the seedlings.
• In young and grown up plants, the first symptom is yellowing of edges of leaves and area around the veins,
i.e. discoloration starts from the margin and spreads towards the midrib.
• The leaves loose their turgidity, gradually turn brown, droop and finally drop off.
• Symptoms start from the older leaves at the base, followed by younger ones towards the top, finally
involving the branches and the whole plant.
• The vascular system of infected plants shows brown discolouration.
Etiology:
• Mycelium :- Septate, branched, light pink
• Conidia :-
Macro conidia - boat shaped, hyaline, long septate, pointed at tip
Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium Asexual fruiting body :- Sporodochia
• Chlamydospore:- spherical, thick walled
Favourable condition:
• Soil temperature of 20-30 ℃
• Hot and dry period followed by rain
• Heavy black soils with on alkaline reaction
• Increased doses of nitrogen fertilizer.
Management:
• Treat the delinted seeds with Carbendazim at 2 g/kg.
• Remove and destroy the infected plant debris after deep ploughing in summer months
• Apply heavy doses of farm yard manure or compost at 100t/ha.
• Follow crop rotation by growing paddy or Lucerne or chrysanthemum for 2-3 years.
• Avoid late season irrigation
• soil solarization effectively control wilt.
Page | 15
• Spot drench with 0.05g/l benomyl or carbendazim 1g/l.
• Apply Trichoderma in FYM
Disease cycle:
• Pathogen survives in soil and plant debris as mycelium and chlamydospores.
• PI: dormant hyphae and chlamydospores in soil.
• Si: conidia and chlamydospores which are carried by water and farm equipment.
BLACK ARM
Xanthomonas compestris pv. Malvacearum
SYMPTOM
Symptoms :-
• The bacterium attacks all stages from seed to harvest.
• Usually five common phases of symptoms are noticed.
• Seedling blight
• Angular leaf spot
• Vein blight or vein necrosis or black vein
• Black arm
• Square rot/Boll rot
Symptom:
i) Seedling blight
• Small, water-soaked, circular or irregular lesions develop on the cotyledons
• later, the infection spreads to stem through petiole and cause withering and death of seedlings.
ii) Angular leaf spot:-
• Small, water soaked areas develop on lower surface of leaves
• enlarge gradually and become angular when restricted by veins and veinlet and
• spots are visible on both the surface of leaves.
• As the lesions become older, they turn to reddish brown colour and infection spreads to veins and veinlet.
iii) Vein blight or vein necrosis or black vein:-
• The infection of veins cause blackening of the veins and
• veinlets, gives a typical 'blighting' appearance.
• On the lower surface of the leaf, bacterial oozes are formed as crusts or scales.
• The affected leaves become crinkled and twisted inward and show withering.
• The infection also spreads from veins to petiole and cause blighting leading to defoliation.
• The infection of veins cause blackening of the veins and veinlets, gives a typical 'blighting' appearance.
• On the lower surface of the leaf, bacterial oozes are formed as crusts or scales.
• The affected leaves become crinkled and twisted inward and show withering.
• Spot drench with 0.05g/l benomyl or carbendazim 1g/l.
• Apply Trichoderma in FYM
Disease cycle:
• Pathogen survives in soil and plant debris as mycelium and chlamydospores.
• PI: dormant hyphae and chlamydospores in soil.
• Si: conidia and chlamydospores which are carried by water and farm equipment.
BLACK ARM
Xanthomonas compestris pv. Malvacearum
SYMPTOM
Symptoms :-
• The bacterium attacks all stages from seed to harvest.
• Usually five common phases of symptoms are noticed.
• Seedling blight
• Angular leaf spot
• Vein blight or vein necrosis or black vein
• Black arm
• Square rot/Boll rot
Symptom:
i) Seedling blight
• Small, water-soaked, circular or irregular lesions develop on the cotyledons
• later, the infection spreads to stem through petiole and cause withering and death of seedlings.
ii) Angular leaf spot:-
• Small, water soaked areas develop on lower surface of leaves
• enlarge gradually and become angular when restricted by veins and veinlet and
• spots are visible on both the surface of leaves.
• As the lesions become older, they turn to reddish brown colour and infection spreads to veins and veinlet.
iii) Vein blight or vein necrosis or black vein:-
• The infection of veins cause blackening of the veins and
• veinlets, gives a typical 'blighting' appearance.
• On the lower surface of the leaf, bacterial oozes are formed as crusts or scales.
• The affected leaves become crinkled and twisted inward and show withering.
• The infection also spreads from veins to petiole and cause blighting leading to defoliation.
• The infection of veins cause blackening of the veins and veinlets, gives a typical 'blighting' appearance.
• On the lower surface of the leaf, bacterial oozes are formed as crusts or scales.
• The affected leaves become crinkled and twisted inward and show withering.
Page | 16
• The infection also spreads from veins to petiole and cause blighting leading to defoliation.
iv) Black arm:-
• On the stem and fruiting branches, dark brown to black lesions are formed, which may girdle the stem
• Gummosis occurs
• Resulting in breaking of the stem
v) Square rot/Boll rot:
• On the bolls water soaked lesions appear and turn into dark black and sunken irregular spots.
• The infection slowly spreads to entire boll and shedding occurs.
ETIOLOGY
• Kingdom - Bacteria
• Gram stain - Negative
• Cell shape - Rod
• Flagella - Monotrichous
• Respiration – Aerobic
• Colony - Straw color to Yellowish and Diffused
FAVOURABLE CONDITION
• Optimum soil temperature of 28°C
• High atmospheric temperature of 28-32°C,
• Relative humidity of 85 percent
• Early sowing
• Delayed thinning
• Poor tillage, late irrigation
• Potassium deficiency in soil
• Rain followed by bright sunshine during the month of October and November are highly favourable.
Management:
• Deep summer ploughing
• Organic manure
• Application of pseudomonas fluorescence
• Delint the cotton seed with concentrated sulphuric acid at 100ml/kg of seeds.
• Treat the delinted seeds with carboxin or oxycarboxin at 2gm/kg or soak the seeds in 1000 ppm streptomycin
sulphate overnight
• Remove and destroy the infected plan debris.
• Rogue out the volunteer cotton plants and weed hosts
• Follow crop rotation with non-host crops
• Early thinning and early earthing up
• Application of potash
• Grow resistant varieties like Khandwa-2, Badnawar-1
• Spray with streptomycin sulphate + Tetracycline mixture 100g along with copper oxychloride at 1.25kg/ha.
Disease cycle:
• The infection also spreads from veins to petiole and cause blighting leading to defoliation.
iv) Black arm:-
• On the stem and fruiting branches, dark brown to black lesions are formed, which may girdle the stem
• Gummosis occurs
• Resulting in breaking of the stem
v) Square rot/Boll rot:
• On the bolls water soaked lesions appear and turn into dark black and sunken irregular spots.
• The infection slowly spreads to entire boll and shedding occurs.
ETIOLOGY
• Kingdom - Bacteria
• Gram stain - Negative
• Cell shape - Rod
• Flagella - Monotrichous
• Respiration – Aerobic
• Colony - Straw color to Yellowish and Diffused
FAVOURABLE CONDITION
• Optimum soil temperature of 28°C
• High atmospheric temperature of 28-32°C,
• Relative humidity of 85 percent
• Early sowing
• Delayed thinning
• Poor tillage, late irrigation
• Potassium deficiency in soil
• Rain followed by bright sunshine during the month of October and November are highly favourable.
Management:
• Deep summer ploughing
• Organic manure
• Application of pseudomonas fluorescence
• Delint the cotton seed with concentrated sulphuric acid at 100ml/kg of seeds.
• Treat the delinted seeds with carboxin or oxycarboxin at 2gm/kg or soak the seeds in 1000 ppm streptomycin
sulphate overnight
• Remove and destroy the infected plan debris.
• Rogue out the volunteer cotton plants and weed hosts
• Follow crop rotation with non-host crops
• Early thinning and early earthing up
• Application of potash
• Grow resistant varieties like Khandwa-2, Badnawar-1
• Spray with streptomycin sulphate + Tetracycline mixture 100g along with copper oxychloride at 1.25kg/ha.
Disease cycle:
Page | 17
PEA
POWDERY MILDEW
Erysiphe pisi
Symptom
• White specks develops on upper surface of leaf
• Later these specks enlarge and cover entire leaf lamina
• Powdery growth spread over stem and pod too.
• The leaves turn yellow and die and defoliated.
• The remain very small and seeds get shriveled.
• These powdery mass are mycelium and conidia of pathogen.
Etiology:
• Sub-Division - Ascomycotina
• Mycelium -septate, branched
• Superficial growth on host, establishing host relationship by haustoria.
• Asexual Spore - conidia (formed in chain on conidiophores)
• Ellipsoidal to barrel shaped, hyaline, single celled
• Conidiophore - Simple, unbranched, non-septate
Favourable Condition:
• Temperature - 20-24°C
• Dry weather
• Rain damage the conidiophore
Management:
Destroy infected crop debris to reduce primary inoculum.
Grow disease free seed preferably certified seed.
Early varieties and early sowing reduce the disease severity.
Spray sulfex/Bavistin/calixin or karathane / Ethirimol
PEA
POWDERY MILDEW
Erysiphe pisi
Symptom
• White specks develops on upper surface of leaf
• Later these specks enlarge and cover entire leaf lamina
• Powdery growth spread over stem and pod too.
• The leaves turn yellow and die and defoliated.
• The remain very small and seeds get shriveled.
• These powdery mass are mycelium and conidia of pathogen.
Etiology:
• Sub-Division - Ascomycotina
• Mycelium -septate, branched
• Superficial growth on host, establishing host relationship by haustoria.
• Asexual Spore - conidia (formed in chain on conidiophores)
• Ellipsoidal to barrel shaped, hyaline, single celled
• Conidiophore - Simple, unbranched, non-septate
Favourable Condition:
• Temperature - 20-24°C
• Dry weather
• Rain damage the conidiophore
Management:
Destroy infected crop debris to reduce primary inoculum.
Grow disease free seed preferably certified seed.
Early varieties and early sowing reduce the disease severity.
Spray sulfex/Bavistin/calixin or karathane / Ethirimol
Page | 18
Grow resistant varieties
Summer deep ploughing
Crop rotation
Disease Cycle:
• Pathogen survive on infected plant debris in the form of (cleistothecium)
• In next season, cleistothecial wall ruptures, ascospores from ascus come out and infect lower leaves.
• Conidia produced on lower leaves infection spread by air and caused secondary infection and this cycle
continue up to crop maturity.
• Pathogen also survive on the annual and perennial host plants in conidial state and recurrently infects the
crop plants whenever available.
DOWNY MILDEW
Peronospora viciae
Symptom:
• Greyish white, mouldy growth appears on lower leaf surface, and a yellowish area appears on the opposite
side of leaf.
• Infected leaves can turn yellow and die.
• Stems may be distorted and stunted.
• Brown blotches appear on pods, and mould may grow inside pods.
Etiology:
• It is an biotroph.
• Sub division: mastigomycotina
• Mycelium: hyaline, coenocytic, intercellular
• Haustoria: finger shaped
• Sporangiophores: hyaline, long, branched dichotomously.
• Sporangia: hyaline. Thin walled, germinate by germtube.
Favourable conditions:
RH: above 80%, temp. 18-23 degree, more conidia production in 13-18 degree.
Management:
• Sanitation
• Crop rotation
• Summer deep ploughing
• Eradication of weed host
• Chemical - Fosetly aluminium 0.2% or Metalaxyl 0.2% or Copper oxychloride are effective
Disease cycle:
• Survives in soil and pea trash and can be seed borne.
• Infected seed can act as primary source for systematic and local infections.
Grow resistant varieties
Summer deep ploughing
Crop rotation
Disease Cycle:
• Pathogen survive on infected plant debris in the form of (cleistothecium)
• In next season, cleistothecial wall ruptures, ascospores from ascus come out and infect lower leaves.
• Conidia produced on lower leaves infection spread by air and caused secondary infection and this cycle
continue up to crop maturity.
• Pathogen also survive on the annual and perennial host plants in conidial state and recurrently infects the
crop plants whenever available.
DOWNY MILDEW
Peronospora viciae
Symptom:
• Greyish white, mouldy growth appears on lower leaf surface, and a yellowish area appears on the opposite
side of leaf.
• Infected leaves can turn yellow and die.
• Stems may be distorted and stunted.
• Brown blotches appear on pods, and mould may grow inside pods.
Etiology:
• It is an biotroph.
• Sub division: mastigomycotina
• Mycelium: hyaline, coenocytic, intercellular
• Haustoria: finger shaped
• Sporangiophores: hyaline, long, branched dichotomously.
• Sporangia: hyaline. Thin walled, germinate by germtube.
Favourable conditions:
RH: above 80%, temp. 18-23 degree, more conidia production in 13-18 degree.
Management:
• Sanitation
• Crop rotation
• Summer deep ploughing
• Eradication of weed host
• Chemical - Fosetly aluminium 0.2% or Metalaxyl 0.2% or Copper oxychloride are effective
Disease cycle:
• Survives in soil and pea trash and can be seed borne.
• Infected seed can act as primary source for systematic and local infections.
Page | 19
• The disease can develop quickly when conditions are cold (5-15 degree) and humid over 90 % for 4-5 days,
often when seedling are in early vegetative stage.
• Individual seedling become infected and act as foci of infection from which disease spread.
• Rain is the major means of spore dispersal and infection.
• Heavy dew will promote sporolution.
PEA RUST
Uromyces fabae
Symptoms:
• The first symptoms appear as tiny, whitish, slightly raised spots on the upper surface of leaves.
• As they enlarge these spots turn powdery and orange or brown in colour and often surrounded by a lighter
halo.
• These pustules also appears on lower side of leaves, stems and pods.
• They may coalesce to form larger pustules.
• In severe infections leaves are shed and plants dry prematurely, the affected plant dries without forming any
seeds in pods or with small shrivelled seeds.
Etiology:
• Sub-division – Basidiomycotina
• Mycelium – Hyaline, Septate, Branched
• Aeciospore – Elliptical, Yellow in colour
• Uredospore – Oval, Light brown, Spiny
• Teliospore – Oval and Thick walled
Favourable conditions:
• High humidity, cloudy or drizzly weather with temperatures 17 to 22°C favour disease development.
• The disease generally occurs during the flowering /early podding stage.
Management:
• Make sure to use healthy seeds from certified sources
• Choose resistant varieties if available
• Plan a crop rotation with a non-host crop
• keep the fields clear of weeds and volunteer plants.
• Monitor the fields for signs of the disease.
• Spray Propiconazole, Tridemorph
• The disease can develop quickly when conditions are cold (5-15 degree) and humid over 90 % for 4-5 days,
often when seedling are in early vegetative stage.
• Individual seedling become infected and act as foci of infection from which disease spread.
• Rain is the major means of spore dispersal and infection.
• Heavy dew will promote sporolution.
PEA RUST
Uromyces fabae
Symptoms:
• The first symptoms appear as tiny, whitish, slightly raised spots on the upper surface of leaves.
• As they enlarge these spots turn powdery and orange or brown in colour and often surrounded by a lighter
halo.
• These pustules also appears on lower side of leaves, stems and pods.
• They may coalesce to form larger pustules.
• In severe infections leaves are shed and plants dry prematurely, the affected plant dries without forming any
seeds in pods or with small shrivelled seeds.
Etiology:
• Sub-division – Basidiomycotina
• Mycelium – Hyaline, Septate, Branched
• Aeciospore – Elliptical, Yellow in colour
• Uredospore – Oval, Light brown, Spiny
• Teliospore – Oval and Thick walled
Favourable conditions:
• High humidity, cloudy or drizzly weather with temperatures 17 to 22°C favour disease development.
• The disease generally occurs during the flowering /early podding stage.
Management:
• Make sure to use healthy seeds from certified sources
• Choose resistant varieties if available
• Plan a crop rotation with a non-host crop
• keep the fields clear of weeds and volunteer plants.
• Monitor the fields for signs of the disease.
• Spray Propiconazole, Tridemorph
Page | 20
• Apply organic manure to boost plant immunity
• Avoid monoculture
• Seed treatment with Thiram.
Disease cycle:
• Rust is an autoecious fungus, completing its life cycle on lentil.
SUGARCANE
WILT
Fusarium sacchari
Symptoms:
• The first symptom of the disease is visible in the canes of 4-5 month age.
• Then gradual yellowing and drying of foliage, shrinkage/withering of canes.
• If the affected canes are cut and examined, the pith will be Light to dark purplish or brown discoloration of
ground tissue, pithiness and boat shaped cavities in the middle of the internodes.
• A characteristic disagreeable odour is also associated with this disease.
• Often a cottony white mycelium is seen in the pith region.
• The affected plants are stunted
Etiology:
• Mycelium:- Septate, branched, light pink
• Conidia :-
Macro conidia - boat shaped, hyaline, long septate, pointed at tip
Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium
• Chlamydospore:- spherical, thick walled
Favourable conditions:
• High day temperature (28-32 °C)
• Low humidity (60-80%)
• Low soil moisture and alkaline soils
• Excess doses of nitrogenous fertilizers
Management:
• Select the seed material from the disease free plots.
• Apply organic manure to boost plant immunity
• Avoid monoculture
• Seed treatment with Thiram.
Disease cycle:
• Rust is an autoecious fungus, completing its life cycle on lentil.
SUGARCANE
WILT
Fusarium sacchari
Symptoms:
• The first symptom of the disease is visible in the canes of 4-5 month age.
• Then gradual yellowing and drying of foliage, shrinkage/withering of canes.
• If the affected canes are cut and examined, the pith will be Light to dark purplish or brown discoloration of
ground tissue, pithiness and boat shaped cavities in the middle of the internodes.
• A characteristic disagreeable odour is also associated with this disease.
• Often a cottony white mycelium is seen in the pith region.
• The affected plants are stunted
Etiology:
• Mycelium:- Septate, branched, light pink
• Conidia :-
Macro conidia - boat shaped, hyaline, long septate, pointed at tip
Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium
• Chlamydospore:- spherical, thick walled
Favourable conditions:
• High day temperature (28-32 °C)
• Low humidity (60-80%)
• Low soil moisture and alkaline soils
• Excess doses of nitrogenous fertilizers
Management:
• Select the seed material from the disease free plots.
Page | 21
• Avoid the practice of rotooning in diseased fields.
• Burn the residue & stubbles in the fields.
• Grow coriander or mustard as a companion crops in early stages of crop.
• Dip the setts in 0.05% carbendazim for 15 minutes
• Grow resistant varieties like Co 617 and B.P.17
• Crop rotation
• Managing root borer
• Avoiding prolonged drought and water logging
• Apply bulk manure
• Apply Trichoderma in FYM
Disease cycle:
• The fungus is soil-borne and remains in the soil as saprophyte for 2-3 years.
• The disease is primarily transmitted through infected seed pieces.
• The secondary spread is aided by wind, rain and irrigation water.
GRASSY SHOOTS
Candidatus phytoplasma
Symptoms:
• Also known as New chlorotic disease, Albino disease, Yellowing disease or Bunchy disease
• Profuse tillering and grassy apperanance of the stem is main symptoms
• Shoots growing from diseased setts remain stunted.
• The leaves are narrow and small, like grass leaves.
• The canes are thin with short internodes, giving a bunchy or grassy appearance to the clump.
• The leaves of infected plants do not produce chlorophyll, and therefore appear white or creamy yellow.
• The leaves appear yellowish and in some cases may be entirely devoid of any pigment
• Lower nodes produce large number of shoots
Etiology:
• Phytoplasmas, formely called Mycoplasma like organisms (MLOS).
• Its large group of obligate, intracellular, wall less, Shape less
• Gram positive Bacteria
• Phylum - Firmicutes
• Class - Mollicutes
• Its found in the Phloem cells of infected plant.
Favourable conditions:
• Dense planting
• Ratooning
• Presence of Insect
• Cloudy days
Management:
• Avoid the practice of rotooning in diseased fields.
• Burn the residue & stubbles in the fields.
• Grow coriander or mustard as a companion crops in early stages of crop.
• Dip the setts in 0.05% carbendazim for 15 minutes
• Grow resistant varieties like Co 617 and B.P.17
• Crop rotation
• Managing root borer
• Avoiding prolonged drought and water logging
• Apply bulk manure
• Apply Trichoderma in FYM
Disease cycle:
• The fungus is soil-borne and remains in the soil as saprophyte for 2-3 years.
• The disease is primarily transmitted through infected seed pieces.
• The secondary spread is aided by wind, rain and irrigation water.
GRASSY SHOOTS
Candidatus phytoplasma
Symptoms:
• Also known as New chlorotic disease, Albino disease, Yellowing disease or Bunchy disease
• Profuse tillering and grassy apperanance of the stem is main symptoms
• Shoots growing from diseased setts remain stunted.
• The leaves are narrow and small, like grass leaves.
• The canes are thin with short internodes, giving a bunchy or grassy appearance to the clump.
• The leaves of infected plants do not produce chlorophyll, and therefore appear white or creamy yellow.
• The leaves appear yellowish and in some cases may be entirely devoid of any pigment
• Lower nodes produce large number of shoots
Etiology:
• Phytoplasmas, formely called Mycoplasma like organisms (MLOS).
• Its large group of obligate, intracellular, wall less, Shape less
• Gram positive Bacteria
• Phylum - Firmicutes
• Class - Mollicutes
• Its found in the Phloem cells of infected plant.
Favourable conditions:
• Dense planting
• Ratooning
• Presence of Insect
• Cloudy days
Management:
Page | 22
• Growing resistant varieties viz., Co 86249, CoG 93076 and CoC 22
• Avoid ratooning
• If disease symptoms are visible within two weeks after planting, such plants can be replaced by healthy
plants.
• Uprooted infected plants and disposed by burning
• Crop rotation
• Grow only certified disease free sett
• Sanitation of field
• Vector control by spraying Imidacloprid, dimethoate
• Sterilize pruning knife after each use
• Treat the setts with aerated steam at 50°C for 1 hour
• Or hot air at 54°C for 8 hours
Disease cycle:
Insect Vector - Leaf Hopper
RATOON STUNTING
Leifsonia xyli subsp. xyli Clavibacter xyli
Symptoms:
• The affected plants are stunted, the stunting being most severe in stubble and ratoon crops
• reduced tillering, thin stalks with shortened internodes and yellowish foliage (mild chlorosis).
• When mature canes are split open, vascular bundles appear discoloured.
• In young canes, orange color is seen in the form of minute pin head like areas near the nodes.
• The disease reduces the length, girth and the number of canes per clump
• The setts taken from diseased plants germinate poorly and the few shoots that are emerged grow very slowly
Etiology:
• Kingdom - Bacteria
• Phylum - Actinobacteria
• Family - Microbacteriaceae
• Gram stain - Positive
• Cell shape - Rod
• Respiration - Aerobic
Favourable conditions:
Infected setts, Dense planting
Management:
• Select healthy setts for planting.
• Field should maintain at proper sanitation.
• Growing resistant varieties viz., Co 86249, CoG 93076 and CoC 22
• Avoid ratooning
• If disease symptoms are visible within two weeks after planting, such plants can be replaced by healthy
plants.
• Uprooted infected plants and disposed by burning
• Crop rotation
• Grow only certified disease free sett
• Sanitation of field
• Vector control by spraying Imidacloprid, dimethoate
• Sterilize pruning knife after each use
• Treat the setts with aerated steam at 50°C for 1 hour
• Or hot air at 54°C for 8 hours
Disease cycle:
Insect Vector - Leaf Hopper
RATOON STUNTING
Leifsonia xyli subsp. xyli Clavibacter xyli
Symptoms:
• The affected plants are stunted, the stunting being most severe in stubble and ratoon crops
• reduced tillering, thin stalks with shortened internodes and yellowish foliage (mild chlorosis).
• When mature canes are split open, vascular bundles appear discoloured.
• In young canes, orange color is seen in the form of minute pin head like areas near the nodes.
• The disease reduces the length, girth and the number of canes per clump
• The setts taken from diseased plants germinate poorly and the few shoots that are emerged grow very slowly
Etiology:
• Kingdom - Bacteria
• Phylum - Actinobacteria
• Family - Microbacteriaceae
• Gram stain - Positive
• Cell shape - Rod
• Respiration - Aerobic
Favourable conditions:
Infected setts, Dense planting
Management:
• Select healthy setts for planting.
• Field should maintain at proper sanitation.
Page | 23
• Remove and burn the clumps showing the disease.
• Sterilization of cutting knives with lysol or any other antiseptic solution.
• Hot air treatment of setts at 54°C for 8 hours or hot water treatment at 50°C for 2 hrs or aerated steam
treatment at 50°C for 1 hour.
Disease cycle:
• The disease spreads through use of diseased setts.
• The disease also spreads through cane harvesting implements contaminated with the juice of the diseased
canes.
• Maize, sorghum, Sudan grass and Cynodon are some of the collateral hosts of the pathogen.
POKKAH BOENG
Fusarium moniliforme or Fusarium subglufinans
Symptoms:
• The general symptoms of Pokkahboeng are mainly of three types;
• Chlorotic Phase
• Acute Phase or Top-Rot Phase
• Knife-cut Phase
• Chlorotic Phase:
Chlorosis at the base of the young leaves and occasionally on the other parts of the leaf blades.
Frequently, wrinkling, twisting and shortening of the leaves accompanied the malformation or distortion of
the young leaves.
The base of the affected leaves is seen often narrower than that of the normal leaves
• Acute Phase or Top-Rot Phase
The most advanced and serious stage
Leaf infection sometimes continued to downward and penetrates in the stalk by way of a growing point.
In advanced stage of infection, the entire base of the spindle and even growing point showed a malformation
of leaves, pronounced wrinkling, twisting and rotting of spindle leaves.
Red specks and stripes also developed.
• Knife-cut Phase:
The symptoms of knife-cut stage are observed in association with the acute phase of the disease
characterized by one or two or even more transverse cuts in the rind of the stalk/stem in such a uniform
manner as if, the tissues are removed with a sharp knife, This is an exaggerated stage of a typical ladder
lesion of a Pokkahboeng disease.
Etiology:
• Remove and burn the clumps showing the disease.
• Sterilization of cutting knives with lysol or any other antiseptic solution.
• Hot air treatment of setts at 54°C for 8 hours or hot water treatment at 50°C for 2 hrs or aerated steam
treatment at 50°C for 1 hour.
Disease cycle:
• The disease spreads through use of diseased setts.
• The disease also spreads through cane harvesting implements contaminated with the juice of the diseased
canes.
• Maize, sorghum, Sudan grass and Cynodon are some of the collateral hosts of the pathogen.
POKKAH BOENG
Fusarium moniliforme or Fusarium subglufinans
Symptoms:
• The general symptoms of Pokkahboeng are mainly of three types;
• Chlorotic Phase
• Acute Phase or Top-Rot Phase
• Knife-cut Phase
• Chlorotic Phase:
Chlorosis at the base of the young leaves and occasionally on the other parts of the leaf blades.
Frequently, wrinkling, twisting and shortening of the leaves accompanied the malformation or distortion of
the young leaves.
The base of the affected leaves is seen often narrower than that of the normal leaves
• Acute Phase or Top-Rot Phase
The most advanced and serious stage
Leaf infection sometimes continued to downward and penetrates in the stalk by way of a growing point.
In advanced stage of infection, the entire base of the spindle and even growing point showed a malformation
of leaves, pronounced wrinkling, twisting and rotting of spindle leaves.
Red specks and stripes also developed.
• Knife-cut Phase:
The symptoms of knife-cut stage are observed in association with the acute phase of the disease
characterized by one or two or even more transverse cuts in the rind of the stalk/stem in such a uniform
manner as if, the tissues are removed with a sharp knife, This is an exaggerated stage of a typical ladder
lesion of a Pokkahboeng disease.
Etiology:
Page | 24
• Mycelium :- Septate, branched, light pink
Conidia :-
Macro conidia - boat shaped, hyaline, long septate, pointed at tip Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium
• Chlamydospore:- spherical, thick walled
Favourable conditions:
• 20-30°C temperature and the average relative humidity higher than 70 to 80% with a cloudy weather,
drizzling rains favors the growth of pathogen.
Management:
• Grow resistant varieties
• Crop rotation
• Managing root borer
• Avoiding prolonged drought and water logging
• Apply bulk manure
• Apply Trichoderma in FYM
• Spray Carbendazim, Propiconazole or Hexaconazole
• Select the seed material from the disease free plots.
• Avoid the practice of rotooning in diseased fields.
• Burn the residue & stubbles in the fields.
• Grow coriander or mustard as a companion crops in early stages of crop.
• Dip the seats in 0.05% carbendazim for 15 minutes
Disease cycle:
• Mycelium :- Septate, branched, light pink
Conidia :-
Macro conidia - boat shaped, hyaline, long septate, pointed at tip Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium
• Chlamydospore:- spherical, thick walled
Favourable conditions:
• 20-30°C temperature and the average relative humidity higher than 70 to 80% with a cloudy weather,
drizzling rains favors the growth of pathogen.
Management:
• Grow resistant varieties
• Crop rotation
• Managing root borer
• Avoiding prolonged drought and water logging
• Apply bulk manure
• Apply Trichoderma in FYM
• Spray Carbendazim, Propiconazole or Hexaconazole
• Select the seed material from the disease free plots.
• Avoid the practice of rotooning in diseased fields.
• Burn the residue & stubbles in the fields.
• Grow coriander or mustard as a companion crops in early stages of crop.
• Dip the seats in 0.05% carbendazim for 15 minutes
Disease cycle:
Page | 25
Turmeric leaf spot
Colletotrichum capsica
Symptom:
• Fungus attacks only leaves and usually infection is confined to leaf blades and occasionally extend to leaf
sheaths • On leaves, elliptical to oblong brown spots with grey centers appear • Spots are about 4-5 cm in
length and 2-3 cm in width.
• They are surrounded by yellow halos
• Spots enlarge and cover a major portion of leaf blade.
• In advanced stages of disease, black dots representing fungal acervuli occur in concentric rings on spot.
• The grey centers become thin and gets teared
• Severely effected leaves dry and wilt
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and Dark
• The mycelium of the fungus is localized in the spot.
• Asexual Spore – Conidia - hyaline, single celled and falcate in shape.
• Asexual fruiting body – Acervullus
• Acervuli with setae arise through epidermis.
• Sexual fruiting body – Perithecia – Pear shaped, In Leaf sheath
• Also produce Chlamydospore
• Colony colour – Black
Favourable conditions:
• Temperature of 21-23 °C. Relative humidity 80%, Intermittent rains, Infected rhizomes, Susceptible variety,
Planting long duration varieties
Management:
• Cultural Management –
✓ The infected and dried leaves should be collected and burnt in order to reduce the inoculum source in the
field
✓ Crop rotations should be followed whenever possible.
✓ Select seed material from disease free areas.
• Varietal Resistance –
✓ Cultivate tolerant varieties like Suguna and Sudarshan
• Biological Management –
✓ Trichoderma spp. is used as a biological control agent.
• Chemical Management –
✓ Treat seed material with mancozeb @ 3g/litre of water or carbendazim @ 1 g/litre of water, for 30 minutes
and shadedry before sowing.
✓ Spray mancozeb @ 2.5 g/litre of water or carbendazim @ 1g/litre; 2- 3 sprays at fortnightly intervals
Disease cycle:
• Survival: pathogen survives in the seed rhizomes or infected plant debris
• Primary infection: mycelium or conidia present in infected plant debris
• Secondary infection: spread through conidia which are carried by wind and water
Turmeric leaf spot
Colletotrichum capsica
Symptom:
• Fungus attacks only leaves and usually infection is confined to leaf blades and occasionally extend to leaf
sheaths • On leaves, elliptical to oblong brown spots with grey centers appear • Spots are about 4-5 cm in
length and 2-3 cm in width.
• They are surrounded by yellow halos
• Spots enlarge and cover a major portion of leaf blade.
• In advanced stages of disease, black dots representing fungal acervuli occur in concentric rings on spot.
• The grey centers become thin and gets teared
• Severely effected leaves dry and wilt
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and Dark
• The mycelium of the fungus is localized in the spot.
• Asexual Spore – Conidia - hyaline, single celled and falcate in shape.
• Asexual fruiting body – Acervullus
• Acervuli with setae arise through epidermis.
• Sexual fruiting body – Perithecia – Pear shaped, In Leaf sheath
• Also produce Chlamydospore
• Colony colour – Black
Favourable conditions:
• Temperature of 21-23 °C. Relative humidity 80%, Intermittent rains, Infected rhizomes, Susceptible variety,
Planting long duration varieties
Management:
• Cultural Management –
✓ The infected and dried leaves should be collected and burnt in order to reduce the inoculum source in the
field
✓ Crop rotations should be followed whenever possible.
✓ Select seed material from disease free areas.
• Varietal Resistance –
✓ Cultivate tolerant varieties like Suguna and Sudarshan
• Biological Management –
✓ Trichoderma spp. is used as a biological control agent.
• Chemical Management –
✓ Treat seed material with mancozeb @ 3g/litre of water or carbendazim @ 1 g/litre of water, for 30 minutes
and shadedry before sowing.
✓ Spray mancozeb @ 2.5 g/litre of water or carbendazim @ 1g/litre; 2- 3 sprays at fortnightly intervals
Disease cycle:
• Survival: pathogen survives in the seed rhizomes or infected plant debris
• Primary infection: mycelium or conidia present in infected plant debris
• Secondary infection: spread through conidia which are carried by wind and water
Page | 26
Chilli
Anthracnose and fruit rot
Colletotrichum capsica
Symptoms:3 stages viz., anthracnose, die back, fruit rot
• Anthracnose:
✓ Disease is more in December – October in transplanted crop
✓ Small, circular to irregular, brownish black scattered spots appear on leaves.
✓ Severely infected leaves defoliate.
• Dieback
✓ The disease causes necrosis of tender twigs from the tip to backward.
✓ The entire branch or the entire top of the plant may wither away.
✓ Numerous black dots (acervuli of fungus) are found scattered all over the necrotic surface of the affected
twigs.
✓ Only the top or few side branches may be killed or in severe attacks the entire plant is withered.
✓ Partially affected plants bear fruit which are few and low quality.
• Fruit rot
✓ Small black circular spots are appeared on the skin of the fruit and spread along the long axis of the
fruit and thus becoming more or less elliptical.
✓ The spots are usually sunken with black margin.
✓ Badly diseased fruit turn straw colour from normal color.
✓ Sunken spots are covered with pinkish mass of fungal spores.
✓ The fruits with many spots drop off prematurely, resulting heavy loss in yield.
✓ Seeds are also infected by this fungus.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and Dark
• The mycelium of the fungus is localized in the spot.
• Asexual Spore – Conidia - hyaline, single celled and falcate in shape.
• Asexual fruiting body – Acervullus
• Acervuli with setae arise through epidermis.
• Sexual fruiting body – Perithecia – Pear shaped, In Leaf sheath
Chilli
Anthracnose and fruit rot
Colletotrichum capsica
Symptoms:3 stages viz., anthracnose, die back, fruit rot
• Anthracnose:
✓ Disease is more in December – October in transplanted crop
✓ Small, circular to irregular, brownish black scattered spots appear on leaves.
✓ Severely infected leaves defoliate.
• Dieback
✓ The disease causes necrosis of tender twigs from the tip to backward.
✓ The entire branch or the entire top of the plant may wither away.
✓ Numerous black dots (acervuli of fungus) are found scattered all over the necrotic surface of the affected
twigs.
✓ Only the top or few side branches may be killed or in severe attacks the entire plant is withered.
✓ Partially affected plants bear fruit which are few and low quality.
• Fruit rot
✓ Small black circular spots are appeared on the skin of the fruit and spread along the long axis of the
fruit and thus becoming more or less elliptical.
✓ The spots are usually sunken with black margin.
✓ Badly diseased fruit turn straw colour from normal color.
✓ Sunken spots are covered with pinkish mass of fungal spores.
✓ The fruits with many spots drop off prematurely, resulting heavy loss in yield.
✓ Seeds are also infected by this fungus.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and Dark
• The mycelium of the fungus is localized in the spot.
• Asexual Spore – Conidia - hyaline, single celled and falcate in shape.
• Asexual fruiting body – Acervullus
• Acervuli with setae arise through epidermis.
• Sexual fruiting body – Perithecia – Pear shaped, In Leaf sheath
Page | 27
• Also produce Chlamydospore
• Colony colour – Black
Disease cycle:
• Seed borne
• Secondary spread is by air borne conidia & rain
• Flies and other insects – responsible for dissemination of the spores from one fruit to another.
Favourable conditions:
• Temp – 28-32 °C
• RH - 95%
• High humid conditions when rain occurs after the fruits have started to ripe
• Susceptible variety.
Management:
• Deep summer ploughing
• Organic manure
• Application of Trichoderma & Pseudomonas fluorescence
• Crop rotation with non host
• Disease free seeds
• Seed treatment with Captan or Thiram 3-4g/kg
• Avoid intercropping with susceptible turmeric cultivars
• Collect and destroy all infected plant parts
• Removal and destruction of Solanaceous weed hosts and infected plant debris
• Spray three times with Captan 1.5% or [email protected]% just before flowering, at fruit formation stage and
15 days after second spray
• Resistant varieties: G3, G4, B61, Lorai, etc.
Leaf curl
Chilli leaf curl virus
Symptom:
• Leaves curl towards midrib and become deformed.
• Intense reduction in leaf size, short internodes, and dwarfing
• Stunted plant growth due to shortened internodes and leaves greatly reduced in size.
• Also produce Chlamydospore
• Colony colour – Black
Disease cycle:
• Seed borne
• Secondary spread is by air borne conidia & rain
• Flies and other insects – responsible for dissemination of the spores from one fruit to another.
Favourable conditions:
• Temp – 28-32 °C
• RH - 95%
• High humid conditions when rain occurs after the fruits have started to ripe
• Susceptible variety.
Management:
• Deep summer ploughing
• Organic manure
• Application of Trichoderma & Pseudomonas fluorescence
• Crop rotation with non host
• Disease free seeds
• Seed treatment with Captan or Thiram 3-4g/kg
• Avoid intercropping with susceptible turmeric cultivars
• Collect and destroy all infected plant parts
• Removal and destruction of Solanaceous weed hosts and infected plant debris
• Spray three times with Captan 1.5% or [email protected]% just before flowering, at fruit formation stage and
15 days after second spray
• Resistant varieties: G3, G4, B61, Lorai, etc.
Leaf curl
Chilli leaf curl virus
Symptom:
• Leaves curl towards midrib and become deformed.
• Intense reduction in leaf size, short internodes, and dwarfing
• Stunted plant growth due to shortened internodes and leaves greatly reduced in size.
Page | 28
• Flower buds abcise before attaining full size and anthers do not contain pollen grains.
• Failure of formation of fruits.
• If fruits are formed, they remain small, deformed and poor in quality.
Etiology:
• Chilli leaf curl virus (ChiLCV)
• Genome – SS- DNA
• Protein coat – Geminate particle
• Genus Begomovirus and Family Geminiviridae.
• This virus is transmitted by whitefly Bemisia tabaci
Favourable conditions:
Presence of virus, Dense planting, High dose of n2 fertilizers, High rh, Cloudy days
Management:
• IDM
• The infected plants should be uprooted and burnt or buried to avoid further infection.
• Avoid monoculture of chilli crop.
• Selection of healthy and disease - free seed.
• Suitable insecticidal sprays reduce the incidence of viral diseases, since majority of viral diseases are
transmitted by insect vectors
• Nursery beds should be covered with nylon net or straw to protect the seedlings from viral infection.
• Raise 2-3 rows of maize or sorghum as border crop to restrict the spread of aphid vectors.
• Apply Imidacloprid in the mainfield to control sucking complex and insect vectors selectively.
• Collect and destroy infected virus plants as soon as they are noticed
CHILLI WILT
Fusarium oxysporum f.sp.capsici
Symptom:
• Initially slight yellowing of the foliage and wilting of the upper leaves occurs
• That progress in a few days into a permanent wilt with the leaves still attached.
• Upward and inward rolling of the leaves.
• Later, the leaves turn yellow and die.
• Generally appear localized in field where a high percentage of the plants wilt and die.
• The vascular system of the plant is discolored, particularly in the lower stem and roots.
Etiology:
• Mycelium :- Septate, branched, light pink
• Conidia :-
o Macro conidia - boat shaped, hyaline, long septate, pointed at tip
o Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium
• Chlamydospore:- spherical, thick walled
Favourable conditions:
• Relatively high soil moisture and soil temperature
• Heavy rainfall, excessive and frequent irrigation
• Flower buds abcise before attaining full size and anthers do not contain pollen grains.
• Failure of formation of fruits.
• If fruits are formed, they remain small, deformed and poor in quality.
Etiology:
• Chilli leaf curl virus (ChiLCV)
• Genome – SS- DNA
• Protein coat – Geminate particle
• Genus Begomovirus and Family Geminiviridae.
• This virus is transmitted by whitefly Bemisia tabaci
Favourable conditions:
Presence of virus, Dense planting, High dose of n2 fertilizers, High rh, Cloudy days
Management:
• IDM
• The infected plants should be uprooted and burnt or buried to avoid further infection.
• Avoid monoculture of chilli crop.
• Selection of healthy and disease - free seed.
• Suitable insecticidal sprays reduce the incidence of viral diseases, since majority of viral diseases are
transmitted by insect vectors
• Nursery beds should be covered with nylon net or straw to protect the seedlings from viral infection.
• Raise 2-3 rows of maize or sorghum as border crop to restrict the spread of aphid vectors.
• Apply Imidacloprid in the mainfield to control sucking complex and insect vectors selectively.
• Collect and destroy infected virus plants as soon as they are noticed
CHILLI WILT
Fusarium oxysporum f.sp.capsici
Symptom:
• Initially slight yellowing of the foliage and wilting of the upper leaves occurs
• That progress in a few days into a permanent wilt with the leaves still attached.
• Upward and inward rolling of the leaves.
• Later, the leaves turn yellow and die.
• Generally appear localized in field where a high percentage of the plants wilt and die.
• The vascular system of the plant is discolored, particularly in the lower stem and roots.
Etiology:
• Mycelium :- Septate, branched, light pink
• Conidia :-
o Macro conidia - boat shaped, hyaline, long septate, pointed at tip
o Micro conidia - small, curved, unicellular
• Conidiophores:- simple, slender, short, produced in sporodochium
• Chlamydospore:- spherical, thick walled
Favourable conditions:
• Relatively high soil moisture and soil temperature
• Heavy rainfall, excessive and frequent irrigation
Page | 29
• poorly drained soil and close spacing
• high soil moisture with temp around 25-30 °C
management:
• Field sanitation
• Remove infected plants debris.
• Apply neem cake or mustard cake to inhibit the growth of pathogen.
• Drenching with 1% Bordeaux mixture or Carbendazim 0.25% or Mancozeb may give protection.
• Seed treatment with 4g Trichoderma formulation or 2g Carbendazim per kg seed is effective.
• Apply Trichoderma mixed with organic manure
• Grow resistant cultivars/lines- DCA-3, DCA-7, DCA-8, DCA-21 and DCA-22
• Crop rotation with non host
• Flooding of filed for 10 days if possible
• Apply organic manure as much as possible
Disease cycle:
Survival: pathogen survives in soil and plant debris as mycelium and chlamydospores
PI: dormant hyphae and chlamydospores in soil.
SI: spread through conidia and chlamydospores which are carried by water and farm equipment
ONION AND GARLIC
Purple blotch pf onion
Alternaria porri
Symptom:
• Leaves - whitish minute dots on leaves with irregular chlorotic areas on tip portion
• Circular to oblong concentric black velvety rings appear in chlorotic area
• Lesions develop towards the base of the leaves
• Leaves die from the tip downwards, break at the point of infection and hang down
• poorly drained soil and close spacing
• high soil moisture with temp around 25-30 °C
management:
• Field sanitation
• Remove infected plants debris.
• Apply neem cake or mustard cake to inhibit the growth of pathogen.
• Drenching with 1% Bordeaux mixture or Carbendazim 0.25% or Mancozeb may give protection.
• Seed treatment with 4g Trichoderma formulation or 2g Carbendazim per kg seed is effective.
• Apply Trichoderma mixed with organic manure
• Grow resistant cultivars/lines- DCA-3, DCA-7, DCA-8, DCA-21 and DCA-22
• Crop rotation with non host
• Flooding of filed for 10 days if possible
• Apply organic manure as much as possible
Disease cycle:
Survival: pathogen survives in soil and plant debris as mycelium and chlamydospores
PI: dormant hyphae and chlamydospores in soil.
SI: spread through conidia and chlamydospores which are carried by water and farm equipment
ONION AND GARLIC
Purple blotch pf onion
Alternaria porri
Symptom:
• Leaves - whitish minute dots on leaves with irregular chlorotic areas on tip portion
• Circular to oblong concentric black velvety rings appear in chlorotic area
• Lesions develop towards the base of the leaves
• Leaves die from the tip downwards, break at the point of infection and hang down
Page | 30
• Bulbs – semi watery rot, shrinkage of the fleshy bulb scales and desiccation followed by these scales
becoming dry and papery.
Etiology:
• Mycelium – Septate, Branched and Dark
• Conidia – Muriform (longitudinal and transverse septation), dark, formed in chain
• Conidiophore – short, dark colored, simple, septate
• Perfect stage – Pleospora
Favourable conditions:
• Warm and Humid climate
• Temperature - 18-25°C
• Intermittent rain
• Cloudy days
• Leaf Minor
Management:
• Chemical treatment
• Summer deep ploughing
• Avoid sprinkler and excess n2 use
• Use trichoderma and pseudomonas
• Avoid monoculturing
disease cycle:
Stemphylium blight of onion and garlic
causal organism: Stemphylium vesicarium
symptom:
• The first symptoms of the disease appear on the radical leaves as small, yellow to pale orange flecks or
streaks in the middle of leaf, which soon become elongated, spindle shaped to ovate spots, surrounded by
characteristic pinkish margin.
• These spots turn grey at the centre and then become brown to dark brown with the development of
conidiophores and conidia of the pathogen.
• Bulbs – semi watery rot, shrinkage of the fleshy bulb scales and desiccation followed by these scales
becoming dry and papery.
Etiology:
• Mycelium – Septate, Branched and Dark
• Conidia – Muriform (longitudinal and transverse septation), dark, formed in chain
• Conidiophore – short, dark colored, simple, septate
• Perfect stage – Pleospora
Favourable conditions:
• Warm and Humid climate
• Temperature - 18-25°C
• Intermittent rain
• Cloudy days
• Leaf Minor
Management:
• Chemical treatment
• Summer deep ploughing
• Avoid sprinkler and excess n2 use
• Use trichoderma and pseudomonas
• Avoid monoculturing
disease cycle:
Stemphylium blight of onion and garlic
causal organism: Stemphylium vesicarium
symptom:
• The first symptoms of the disease appear on the radical leaves as small, yellow to pale orange flecks or
streaks in the middle of leaf, which soon become elongated, spindle shaped to ovate spots, surrounded by
characteristic pinkish margin.
• These spots turn grey at the centre and then become brown to dark brown with the development of
conidiophores and conidia of the pathogen.
Page | 31
• Similar symptoms appear on the inflorescence stalks.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Branched, Dark, Septate
• Conidiophores are straight to curved, 1-4 septa, simple or branched, light yellow brown to medium golden
brown in colour
• Conidia – Vertical + Horizontal septa present
• Colony – Black (Concentric ring present)
Favourable conditions:
• Warm and Humid climate
• Temperature - 18-25°C
• Leaf wetness period > 12 hours favour disease development
• Intermittent rain
• Cloudy days
Management:
• collection and destruction of plant debris
• crop rotation
• summer ploughings
• Sprays of mancozeb (0.25%)
• Proper spacing for air circulation
• Ensure adequate drainage before planting.
• Avoid excessive nitrogen applications which can increase disease severity
• Remove and bury plant debris and culls through cultivation after harvest
• Use crop rotation for a period of 3-4 year
• Application of BCA – Trichoderma
• Organic Manure
• Neem cake
Disease cycle:
CORIANDER STEM GALL
• Similar symptoms appear on the inflorescence stalks.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Branched, Dark, Septate
• Conidiophores are straight to curved, 1-4 septa, simple or branched, light yellow brown to medium golden
brown in colour
• Conidia – Vertical + Horizontal septa present
• Colony – Black (Concentric ring present)
Favourable conditions:
• Warm and Humid climate
• Temperature - 18-25°C
• Leaf wetness period > 12 hours favour disease development
• Intermittent rain
• Cloudy days
Management:
• collection and destruction of plant debris
• crop rotation
• summer ploughings
• Sprays of mancozeb (0.25%)
• Proper spacing for air circulation
• Ensure adequate drainage before planting.
• Avoid excessive nitrogen applications which can increase disease severity
• Remove and bury plant debris and culls through cultivation after harvest
• Use crop rotation for a period of 3-4 year
• Application of BCA – Trichoderma
• Organic Manure
• Neem cake
Disease cycle:
CORIANDER STEM GALL
Page | 32
Protomyces macrosporus
Symptoms:
• The disease appears in the form of tumor-like swellings of leaf veins, leaf stalks, peduncles, stems as well as
fruits.
• The infected veins show a swollen hanging appearance to the leaves.
• Initially the tumors are glossy which rupture later on and become rough.
• They are about 3 mm broad and up to 12.5 mm long.
• Badly affected plants may be killed. In the presence of excessive soil moisture, especially under shaded
conditions, when the stem fails to harden and remain succulent, the tumors are numerous.
Etiology:
• Sub-Division – Ascomycotina
• Class – Hemiascomycetes
• Mycelium - Septate and Branched, Hyaline
• Sexual spore – Ascospore, Developed on asci
• Asci developed naked on Mycelium
• Ascospore multiply like yeast cell
Favourable conditions:
• 20-25℃
• >80% RH
• Dense planting
• Excessive soil moisture
• Shades
Management:
• Deep ploughing of fields during summer
• Soil solarization: Cover the beds with polythene sheet of 45 gauge (0.45 mm) thickness for three weeks
before sowing for soil solarization which will help in reducing the soilborne pests
• Timely and line sowing should be done.
• Avoid overcrowding
• Field sanitation
• Rouging
• Destroy the weeds
• Soil test based application of manures and fertilizers.
• Apply Trichoderma
• Maintain the optimum moisture to minimize the stem gall.
• Hexaconazole as seed treatment (0.2%) and foliar spray after 40,60 and 75 DAS (0.2%) is more effective
treatment for management of stem gall disease of coriander
Disease cycle:
Protomyces macrosporus
Symptoms:
• The disease appears in the form of tumor-like swellings of leaf veins, leaf stalks, peduncles, stems as well as
fruits.
• The infected veins show a swollen hanging appearance to the leaves.
• Initially the tumors are glossy which rupture later on and become rough.
• They are about 3 mm broad and up to 12.5 mm long.
• Badly affected plants may be killed. In the presence of excessive soil moisture, especially under shaded
conditions, when the stem fails to harden and remain succulent, the tumors are numerous.
Etiology:
• Sub-Division – Ascomycotina
• Class – Hemiascomycetes
• Mycelium - Septate and Branched, Hyaline
• Sexual spore – Ascospore, Developed on asci
• Asci developed naked on Mycelium
• Ascospore multiply like yeast cell
Favourable conditions:
• 20-25℃
• >80% RH
• Dense planting
• Excessive soil moisture
• Shades
Management:
• Deep ploughing of fields during summer
• Soil solarization: Cover the beds with polythene sheet of 45 gauge (0.45 mm) thickness for three weeks
before sowing for soil solarization which will help in reducing the soilborne pests
• Timely and line sowing should be done.
• Avoid overcrowding
• Field sanitation
• Rouging
• Destroy the weeds
• Soil test based application of manures and fertilizers.
• Apply Trichoderma
• Maintain the optimum moisture to minimize the stem gall.
• Hexaconazole as seed treatment (0.2%) and foliar spray after 40,60 and 75 DAS (0.2%) is more effective
treatment for management of stem gall disease of coriander
Disease cycle:
Page | 33
MARIGOLD
BOTRYTIS BLIGHT
Botrytis cinerea
Symptom:
• Flower parts develop water-soaked lesions that become necrotic and die.
• A gray mass of spores develops on necrotic tissue during wet conditions.
• Entire petals or flowers may become diseased.
• Senescent leaves may also be attacked.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia (Globose)
• Conidiophore – Highly branched
• Colony color – Dark
• Produce sclerotia
Favourable conditions:
• Prolonged periods of free moisture favour infection
• For conidial germination, 18 to 25℃ temperature and relative humidity between 93 to 100 per cent is
optimum
Management:
• Practice good sanitation. Remove and destroy all infected plant parts as soon as they are observed.
• Avoid overhead watering. Water on foliage and flowers from overhead irrigation, especially on cool, cloudy
days, promotes the disease. Try to keep buds and flowers dry. Water early in the day so the plants have
enough time to dry off completely.
• Avoid overcrowding, Give adequate space between plants to allow for good air circulation. The fungus thrives
in areas that are cool and moist and where plants are overcrowded.
• Use fungicides. Depending upon the susceptibility of the plant to this disease, spray every 10 days with a
fungicide. captan, chlorothalonil (Daconil), mancozeb, maneb, sulfur, and thiophanate methyl .
• Fungicides must be applied in advance of the disease as a protectant.
Disease cycle:
• Botrytis fungi overwinter as sclerotia on dead plant debris in the garden.
• In the spring, spores form and spread by wind or splashing water to infect dying, wounded, or extremely soft
plant tissues.
MARIGOLD
BOTRYTIS BLIGHT
Botrytis cinerea
Symptom:
• Flower parts develop water-soaked lesions that become necrotic and die.
• A gray mass of spores develops on necrotic tissue during wet conditions.
• Entire petals or flowers may become diseased.
• Senescent leaves may also be attacked.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia (Globose)
• Conidiophore – Highly branched
• Colony color – Dark
• Produce sclerotia
Favourable conditions:
• Prolonged periods of free moisture favour infection
• For conidial germination, 18 to 25℃ temperature and relative humidity between 93 to 100 per cent is
optimum
Management:
• Practice good sanitation. Remove and destroy all infected plant parts as soon as they are observed.
• Avoid overhead watering. Water on foliage and flowers from overhead irrigation, especially on cool, cloudy
days, promotes the disease. Try to keep buds and flowers dry. Water early in the day so the plants have
enough time to dry off completely.
• Avoid overcrowding, Give adequate space between plants to allow for good air circulation. The fungus thrives
in areas that are cool and moist and where plants are overcrowded.
• Use fungicides. Depending upon the susceptibility of the plant to this disease, spray every 10 days with a
fungicide. captan, chlorothalonil (Daconil), mancozeb, maneb, sulfur, and thiophanate methyl .
• Fungicides must be applied in advance of the disease as a protectant.
Disease cycle:
• Botrytis fungi overwinter as sclerotia on dead plant debris in the garden.
• In the spring, spores form and spread by wind or splashing water to infect dying, wounded, or extremely soft
plant tissues.
Page | 34
• Fungal mycelial strands (web blight) from previously infected plant parts can grow onto healthy plant parts
and infect them
ROSE
DIEBACK
Botrytis cinerea
Symptom:
• Browning and Dieback of the tips of young shoots in spring
• Browning and Dieback of a pruning stub, which the progresses further down the branch
• Dieback of twigs, branches, main stem or even the whole plant at any time of year
• Fungal structure, such as tiny black fruiting bodies, are sometime visible on the affected parts of the plant.
• In some instances there may also be associated root decay.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia (Globose)
• Conidiophore – Highly branched
• Colony color – Dark ▪ Produce sclerotia
Favourable condition:
• Both overwatering and underwatering can cause this problem.
• Another cause is poor soil quality with no proper nutrients.
• Cloudy days ▪ 20-25 ℃
• High RH
Management:
• Sanitation
• Sterilization of pruning knife
• Fungal mycelial strands (web blight) from previously infected plant parts can grow onto healthy plant parts
and infect them
ROSE
DIEBACK
Botrytis cinerea
Symptom:
• Browning and Dieback of the tips of young shoots in spring
• Browning and Dieback of a pruning stub, which the progresses further down the branch
• Dieback of twigs, branches, main stem or even the whole plant at any time of year
• Fungal structure, such as tiny black fruiting bodies, are sometime visible on the affected parts of the plant.
• In some instances there may also be associated root decay.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia (Globose)
• Conidiophore – Highly branched
• Colony color – Dark ▪ Produce sclerotia
Favourable condition:
• Both overwatering and underwatering can cause this problem.
• Another cause is poor soil quality with no proper nutrients.
• Cloudy days ▪ 20-25 ℃
• High RH
Management:
• Sanitation
• Sterilization of pruning knife
Page | 35
• Proper organic manure
• Regular pruning
• Maintain proper spacing
• Proper soil drainage
• Avoid injury the plant during transplanting
• Paste fungicides (Bordeaux paste) on cut portion
• Spray Carbendazim, Mancozeb
• Proper nutrition
• Regular watering
• Proper sunlight
• Spray Trichoderma
Disease cycle:
POWDERY MILDEW OF ROSE
Podosphaera pannosa
Symptom:
• Small powdery white patches appears on all aerial part of plant
• In case of severe attack, plants may become stunted, leaves may curl, become dried, and drop.
• Unopened buds, young stems, and thorns may be entirely overgrown with the powdery coating.
Etiology:
• Sub-Division – Ascomycotina
• Mycelium -septate, branched ◼ Superficial growth on host, establishing host relationship by haustoria.
• Asexual Spore - conidia ( formed in chain on conidiophores)
• Ellipsoidal to barrel shaped, hyaline, single celled
• Conidiophore – Simple, unbranched, non-septate
• Ceistothecia - closed structures having appendages (Branched Dichotomously)
• Asci - broadly elliptic to sub globose
• Ascospores - Each ascus contains 8 ascospores
Favourable conditions:
RH 70%, Temperature – 20-25℃, Monocropping
• Proper organic manure
• Regular pruning
• Maintain proper spacing
• Proper soil drainage
• Avoid injury the plant during transplanting
• Paste fungicides (Bordeaux paste) on cut portion
• Spray Carbendazim, Mancozeb
• Proper nutrition
• Regular watering
• Proper sunlight
• Spray Trichoderma
Disease cycle:
POWDERY MILDEW OF ROSE
Podosphaera pannosa
Symptom:
• Small powdery white patches appears on all aerial part of plant
• In case of severe attack, plants may become stunted, leaves may curl, become dried, and drop.
• Unopened buds, young stems, and thorns may be entirely overgrown with the powdery coating.
Etiology:
• Sub-Division – Ascomycotina
• Mycelium -septate, branched ◼ Superficial growth on host, establishing host relationship by haustoria.
• Asexual Spore - conidia ( formed in chain on conidiophores)
• Ellipsoidal to barrel shaped, hyaline, single celled
• Conidiophore – Simple, unbranched, non-septate
• Ceistothecia - closed structures having appendages (Branched Dichotomously)
• Asci - broadly elliptic to sub globose
• Ascospores - Each ascus contains 8 ascospores
Favourable conditions:
RH 70%, Temperature – 20-25℃, Monocropping
Page | 36
Management:
• Clean up and dispose of fallen leaves and debris surrounding plants.
• Prune infected plant parts and dispose them properly.
• Provide plants with adequate nutrients and water to maintain their immunity
• Keep the soil well watered and mulched to prevent moisture loss and to cover up overwintering spores.
• Space plants far enough apart to provide good air circulation and prune them regularly to prevent
overcrowding.
• Use fans to provide adequate ventilation during humid nights.
• Water the roses in morning so the foliage can dry rapidly and to avoid infection by other fungal pathogens.
• Use fungicides as a preventive measure during optimal growth conditions.
• Chemical - Fungicides such as propiconazole & hexaconazole
Disease cycle:
BLACK LEAF SPOT
Diplocarpon rosae
Symptom:
• Black spots, one-tenth to one-half inch in diameter, develop first on upper leaf surfaces.
• Areas adjacent to the black spots turn yellow and leaves drop prematurely,
• Usually symptoms first appears at the bottom of the plant and progressing upward. Fungus may also attack
stems and flowers of rose bushes
• On stems, infected areas are blackened with blistered appearance dotted with pustules.
Etiology:
• Sub-Division – Ascomycotina
• Class – Discomycetes
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia – Bicelled
• Asexual fruiting body – Acervullus
• Conidiophore - Simple, vertical, unbranched
• Sexual Spore – Ascospore in Sexual fruiting body – Apothecia
Management:
• Clean up and dispose of fallen leaves and debris surrounding plants.
• Prune infected plant parts and dispose them properly.
• Provide plants with adequate nutrients and water to maintain their immunity
• Keep the soil well watered and mulched to prevent moisture loss and to cover up overwintering spores.
• Space plants far enough apart to provide good air circulation and prune them regularly to prevent
overcrowding.
• Use fans to provide adequate ventilation during humid nights.
• Water the roses in morning so the foliage can dry rapidly and to avoid infection by other fungal pathogens.
• Use fungicides as a preventive measure during optimal growth conditions.
• Chemical - Fungicides such as propiconazole & hexaconazole
Disease cycle:
BLACK LEAF SPOT
Diplocarpon rosae
Symptom:
• Black spots, one-tenth to one-half inch in diameter, develop first on upper leaf surfaces.
• Areas adjacent to the black spots turn yellow and leaves drop prematurely,
• Usually symptoms first appears at the bottom of the plant and progressing upward. Fungus may also attack
stems and flowers of rose bushes
• On stems, infected areas are blackened with blistered appearance dotted with pustules.
Etiology:
• Sub-Division – Ascomycotina
• Class – Discomycetes
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia – Bicelled
• Asexual fruiting body – Acervullus
• Conidiophore - Simple, vertical, unbranched
• Sexual Spore – Ascospore in Sexual fruiting body – Apothecia
Page | 37
Favourable conditions:
Temperature 20–26°C, High RH >90%, Presence of free water in plant surface, Shade, Susceptible variety
Management:
• Remove diseased leaves. As soon as diseased leaves are noticed, remove and dispose of them.
• Dead leaves on the ground should also be collected and destroyed.
• Compost only if this material will not be used back in rose beds.
• To minimize overwintering of the fungus, collect and remove all leaves from the ground in the fall, mulch
with 2– 3 inches of leaf mould or fine bark, and prune diseased canes before growth begins in spring.
• Keep the foliage dry. The fungal spores need a wet surface to germinate and cause infection. Therefore, keep
the foliage as dry as possible.
• Do not use overhead watering, or if you do, water early in the day so the foliage is dry by night time.
• Prune plants to allow more air circulation and facilitate the drying of foliage.
• Move the plants - You can limit the disease by growing roses in locations where they receive morning or,
preferably, all day sun. This facilitates drying of the foliage.
• Resistant varieties: Bebe bune, Coronado, Grand opera, Sphinx
• Spray Tridemorph 0.1% at weekly intervals starting with the sprouting of the plants till new foliage appears.
Disease cycle:
• Survival - in fallen leaves and lesions on stems
• PI - Spores are splashed onto the leaves and cause infection when provided with seven hours of moisture,
and optimal temperatures ranging between 20-26°C with high relative humidity.
• SI - Within two weeks of infection and the necessary moisture and temperatures, more spores are produced,
allowing for rapid infection of nearby healthy rose plants during the growing season.
CUCURBITS
DOWNY MILDEW
Pseudoperonospora cubensis
Symptoms:
• Angular lesions that are limited by leaf veins.
• During periods of leaf wetness from dew, irrigation or rainfall, incipient lesions can become conspicuously
water soaked.
• Severe infection results in leaves that are completely dead and curled up.
• Also called as wildfire as leaves appears to be burned.
• Irregular shaped lesions on foliage that turns brown rapidally.
Favourable conditions:
Temperature 20–26°C, High RH >90%, Presence of free water in plant surface, Shade, Susceptible variety
Management:
• Remove diseased leaves. As soon as diseased leaves are noticed, remove and dispose of them.
• Dead leaves on the ground should also be collected and destroyed.
• Compost only if this material will not be used back in rose beds.
• To minimize overwintering of the fungus, collect and remove all leaves from the ground in the fall, mulch
with 2– 3 inches of leaf mould or fine bark, and prune diseased canes before growth begins in spring.
• Keep the foliage dry. The fungal spores need a wet surface to germinate and cause infection. Therefore, keep
the foliage as dry as possible.
• Do not use overhead watering, or if you do, water early in the day so the foliage is dry by night time.
• Prune plants to allow more air circulation and facilitate the drying of foliage.
• Move the plants - You can limit the disease by growing roses in locations where they receive morning or,
preferably, all day sun. This facilitates drying of the foliage.
• Resistant varieties: Bebe bune, Coronado, Grand opera, Sphinx
• Spray Tridemorph 0.1% at weekly intervals starting with the sprouting of the plants till new foliage appears.
Disease cycle:
• Survival - in fallen leaves and lesions on stems
• PI - Spores are splashed onto the leaves and cause infection when provided with seven hours of moisture,
and optimal temperatures ranging between 20-26°C with high relative humidity.
• SI - Within two weeks of infection and the necessary moisture and temperatures, more spores are produced,
allowing for rapid infection of nearby healthy rose plants during the growing season.
CUCURBITS
DOWNY MILDEW
Pseudoperonospora cubensis
Symptoms:
• Angular lesions that are limited by leaf veins.
• During periods of leaf wetness from dew, irrigation or rainfall, incipient lesions can become conspicuously
water soaked.
• Severe infection results in leaves that are completely dead and curled up.
• Also called as wildfire as leaves appears to be burned.
• Irregular shaped lesions on foliage that turns brown rapidally.
Page | 38
• Early lesions are light green in appearance and become chlorotic and finally mecrotic as host cells die.
Etiology:
• The mycelium is coenocytic and intercellular with small, ovate haustorea which sometimes develop finger-
like branches.
• The sporangiophores arise singly or in groups of 2-5 through the stomata.
• The upper third of the sporangiophore is branched dichotomously or intermediate between dichotomous
and trichotomous branching habit.
• The sporangia are grayish to olivaceous purple, ovoid to elliptical, thin walled and with a papilla at the distal
end, 21-39 X 14-23 µ in size.
• The germination of sporangia occurs by production of biflagellate zoospores which are 10-13 microns in
diameter when in resting stage.
• The zoospores are spherical, rarely obovoid to ellipsoid, light yellow, and smooth walled. They measure 19-22
microns in diameter.
Favourable conditions:
• Free moisture on leaf surface is essential for germination of sporangia.
• The optimum temperature for germination and zoospores production lies between 15 and 20.c.
• Low relative humidity favours dispersal of sporangia.
Management:
• Some of the cultural practices that help in reducing losses from the downy mildew are early sowing,
destruction of weed hosts, proper nutrition and reducing the amount of moisture among the vines.
• The spraying of some protectant fungicides like Mancozeb, Zineb and Tricop-50 (tribasic copper sulphate) @
0.2-0.3 % at 5-7 days intervals.
• Other fungicides that have been used are Difolatan & chlorothalonil.
• Ridomil (Metalexyl + Mancozeb) @ 0.2 % is more effective in controlling the disease.
• Use of resistant variety. (LC-8 and PPDMR-4 were identified as resistant to downy mildew).
Disease cycle:
Powdery mildew
Sphaerotheca fuliginea Erysiphe cichoracearum
Symptoms:
• Early lesions are light green in appearance and become chlorotic and finally mecrotic as host cells die.
Etiology:
• The mycelium is coenocytic and intercellular with small, ovate haustorea which sometimes develop finger-
like branches.
• The sporangiophores arise singly or in groups of 2-5 through the stomata.
• The upper third of the sporangiophore is branched dichotomously or intermediate between dichotomous
and trichotomous branching habit.
• The sporangia are grayish to olivaceous purple, ovoid to elliptical, thin walled and with a papilla at the distal
end, 21-39 X 14-23 µ in size.
• The germination of sporangia occurs by production of biflagellate zoospores which are 10-13 microns in
diameter when in resting stage.
• The zoospores are spherical, rarely obovoid to ellipsoid, light yellow, and smooth walled. They measure 19-22
microns in diameter.
Favourable conditions:
• Free moisture on leaf surface is essential for germination of sporangia.
• The optimum temperature for germination and zoospores production lies between 15 and 20.c.
• Low relative humidity favours dispersal of sporangia.
Management:
• Some of the cultural practices that help in reducing losses from the downy mildew are early sowing,
destruction of weed hosts, proper nutrition and reducing the amount of moisture among the vines.
• The spraying of some protectant fungicides like Mancozeb, Zineb and Tricop-50 (tribasic copper sulphate) @
0.2-0.3 % at 5-7 days intervals.
• Other fungicides that have been used are Difolatan & chlorothalonil.
• Ridomil (Metalexyl + Mancozeb) @ 0.2 % is more effective in controlling the disease.
• Use of resistant variety. (LC-8 and PPDMR-4 were identified as resistant to downy mildew).
Disease cycle:
Powdery mildew
Sphaerotheca fuliginea Erysiphe cichoracearum
Symptoms:
Page | 39
• On upper surface of leaves, small white or greyish superficial spots appears.
• Sometimes on stem too
• Cover entire leaf lamina
• Cause necrosis
• Cause Defoliation
• Fruits remains small and deformed,
• Yield also reduced
Etiology:
• Sub-Division – Ascomycotina
• Mycelium -septate, branched
• Superficial growth on host, establishing host relationship by haustoria.
• Asexual Spore - conidia ( formed in chain on conidiophores)
• Ellipsoidal to barrel shaped, hyaline, single celled
• Conidiophore – Simple, unbranched, non-septate
• Ceistothecia - closed structures having appendages (Myceloid / Simple)
• Asci - broadly elliptic to sub globose
• Ascospores - Each ascus contains 8 ascospores
Favourable conditions:
RH 70%, Temperature – 20-25℃, Monocropping
Management:
• Clean cultivation
• Crop rotation
• Proper spacing
• Remove weed host
• Use of biocontrol agent – Ampelomyces Quisqualis
• Verticillium lecanii
• CHEMICAL CONTROL - Fungicides such as triadimefon and propiconazole, effective chemical control is also
possible with hexaconazole, penconazole.
Disease cycle:
WILT
• On upper surface of leaves, small white or greyish superficial spots appears.
• Sometimes on stem too
• Cover entire leaf lamina
• Cause necrosis
• Cause Defoliation
• Fruits remains small and deformed,
• Yield also reduced
Etiology:
• Sub-Division – Ascomycotina
• Mycelium -septate, branched
• Superficial growth on host, establishing host relationship by haustoria.
• Asexual Spore - conidia ( formed in chain on conidiophores)
• Ellipsoidal to barrel shaped, hyaline, single celled
• Conidiophore – Simple, unbranched, non-septate
• Ceistothecia - closed structures having appendages (Myceloid / Simple)
• Asci - broadly elliptic to sub globose
• Ascospores - Each ascus contains 8 ascospores
Favourable conditions:
RH 70%, Temperature – 20-25℃, Monocropping
Management:
• Clean cultivation
• Crop rotation
• Proper spacing
• Remove weed host
• Use of biocontrol agent – Ampelomyces Quisqualis
• Verticillium lecanii
• CHEMICAL CONTROL - Fungicides such as triadimefon and propiconazole, effective chemical control is also
possible with hexaconazole, penconazole.
Disease cycle:
WILT
Page | 40
Erwinia tracheiphila
Symptom:
• Symptoms appear as young plants because the bacterium has blocked the xylem.
• First symptom appear about 4 to 21 days after transmission.
• The area around wound becoming dark green, and later entire plant shows a dull green colour.
• Seedling are usually more susceptible to infection because they collapse faster the full grown plants.
• The disease can be diagnosed in the field by cutting the wilted stem, joining the cut parts together and then
observing the gummy ooze when the ends are slowly pulled apart.
• Fruit on vines may fail to mature, resulting in economic loss.
Etiology:
• Kingdom – Bacteria
• Gram stain – Negative
• Cell shape – Rod
• Flagella – Peritrichous
• Respiration - Aerobic ▪ Colony – Straw color to Yellowish and Diffused
favourable conditions:
• Mono cropping of cucurbits plantation.
• Stripped cucumber beetle population
• Dense cropping
• High dose of N2 Fertilizer
• High relative humidity
• Cloudy days
Management:
• In general, more bacterial wilt is seen on the edges of fields where beetles first encounter plants.
• Larger plantings must be protected by insecticides.
• Carbaryl, Malathion, or rotenone insecticides or combination products are registered to treat cucumber
beetles.
• They will provide control of the beetles if applied when beetles first appear in the spring.
• Avoid mono-cropping of cucurbits
• Sanitation
• Removes weeds
• Collect disease free seeds
• Cover the rows with organic mulch or polythene
• Apply neem oil every forth night
Disease cycle:
• Primary infection: Bacteria survive on striped cucumber beetle.
• Secondary infection: Spread by striped cucumber beetle.
Erwinia tracheiphila
Symptom:
• Symptoms appear as young plants because the bacterium has blocked the xylem.
• First symptom appear about 4 to 21 days after transmission.
• The area around wound becoming dark green, and later entire plant shows a dull green colour.
• Seedling are usually more susceptible to infection because they collapse faster the full grown plants.
• The disease can be diagnosed in the field by cutting the wilted stem, joining the cut parts together and then
observing the gummy ooze when the ends are slowly pulled apart.
• Fruit on vines may fail to mature, resulting in economic loss.
Etiology:
• Kingdom – Bacteria
• Gram stain – Negative
• Cell shape – Rod
• Flagella – Peritrichous
• Respiration - Aerobic ▪ Colony – Straw color to Yellowish and Diffused
favourable conditions:
• Mono cropping of cucurbits plantation.
• Stripped cucumber beetle population
• Dense cropping
• High dose of N2 Fertilizer
• High relative humidity
• Cloudy days
Management:
• In general, more bacterial wilt is seen on the edges of fields where beetles first encounter plants.
• Larger plantings must be protected by insecticides.
• Carbaryl, Malathion, or rotenone insecticides or combination products are registered to treat cucumber
beetles.
• They will provide control of the beetles if applied when beetles first appear in the spring.
• Avoid mono-cropping of cucurbits
• Sanitation
• Removes weeds
• Collect disease free seeds
• Cover the rows with organic mulch or polythene
• Apply neem oil every forth night
Disease cycle:
• Primary infection: Bacteria survive on striped cucumber beetle.
• Secondary infection: Spread by striped cucumber beetle.
Page | 41
POTATO
EARLY BLIGHT
Alternaria solani
Symptom:
• This is a common disease of tomato occurring on the foliage at any stage of the growth.
• As small, black lesions mostly on the older foliage.
• Spots enlarge up to 3-4 cm in diameter or larger
• concentric rings developed in the centre of the diseased area.
• Seedling infection cause collar rot
• Tissue surrounding the spots may turn yellow
• If high temperature and humidity occur at this time, much of the foliage is killed.
• Lesions on the stems are similar to those on leaves, sometimes girdling the plant if they occur near the soil
line.
Etiology:
• Mycelium – Septate, Branched and Dark
• Conidia – Muriform (longitudinal and transverse septation), dark, formed in chain
• Conidiophore – short, dark colored, simple, septate
• Perfect stage – Pleospora
Favourable conditions:
• Early blight is principally a disease of aging plant tissue.
• Lesions generally appear quickly under warm, moist conditions on older foliage and are usually visible within
5-7 days after infection.
• A long wet period is required for sporulation but it can also occur under conditions of alternating wet and dry
periods.
• T = 24-30 ℃
• RH = >90%
• Cloudy days
Management:
• Prune or stake plants to improve air circulation and reduce fungal problems.
• Keep the soil under plants clean and free of debris.
• Add a layer of organic compost to prevent the spores from splashing back up onto vegetation.
• Drip irrigation can be used to help keep the foliage dry.
• Crop rotation with non host
• Removal and burning of infected crop debris and weed host
POTATO
EARLY BLIGHT
Alternaria solani
Symptom:
• This is a common disease of tomato occurring on the foliage at any stage of the growth.
• As small, black lesions mostly on the older foliage.
• Spots enlarge up to 3-4 cm in diameter or larger
• concentric rings developed in the centre of the diseased area.
• Seedling infection cause collar rot
• Tissue surrounding the spots may turn yellow
• If high temperature and humidity occur at this time, much of the foliage is killed.
• Lesions on the stems are similar to those on leaves, sometimes girdling the plant if they occur near the soil
line.
Etiology:
• Mycelium – Septate, Branched and Dark
• Conidia – Muriform (longitudinal and transverse septation), dark, formed in chain
• Conidiophore – short, dark colored, simple, septate
• Perfect stage – Pleospora
Favourable conditions:
• Early blight is principally a disease of aging plant tissue.
• Lesions generally appear quickly under warm, moist conditions on older foliage and are usually visible within
5-7 days after infection.
• A long wet period is required for sporulation but it can also occur under conditions of alternating wet and dry
periods.
• T = 24-30 ℃
• RH = >90%
• Cloudy days
Management:
• Prune or stake plants to improve air circulation and reduce fungal problems.
• Keep the soil under plants clean and free of debris.
• Add a layer of organic compost to prevent the spores from splashing back up onto vegetation.
• Drip irrigation can be used to help keep the foliage dry.
• Crop rotation with non host
• Removal and burning of infected crop debris and weed host
Page | 42
• Application of organic manure
• Spray Mancozeb 2 kg/ha in 15 days interval.
Disease cycle:
LATE BLIGHT
Phytopthora infestans
Symptoms:
• Water soaked lesions appears on edge of leaves
• Later it turns to large, brown patches with a green gray edge; not confined by major leaf veins.
• Infections progress through leaflets and petioles, resulting in large sections of brown foliage
• Lesions also girdle the Stem
• Dark brown, circular spots cover large parts of fruits, leading to dry brown rot
• In high humidity, thin powdery white fungal growth appears on infected leaves and stems.
• In cool, wet weather, entire fields turn brown and wilted
• Some time the plants look like stem without any single leaf.
• Symptoms also extended to tuber portion either in fields or during harvesting and storage.
• Brown discolorations are seen on the skin of the potato tuber followed by decaying and rotting of tubers
Etiology:
• The pathogen produces non-septate and hyaline mycelium.
• Sporangiophores emerge through the stomata on the lower surface singly or in groups.
• They are unbranched and bear single celled, hyaline, round or oval sporangia at the tip singly.
• The sporangia germinate to produce abundant zoospores.
• The fungus also produces oospores and chlamydospores in adverse seasons.
Favourable conditions:
T = 20-22°C, >90% RH, Cloudy days, Intermittent rains, Dense cropping, Poor drainage of soil
Management:
• Application of organic manure
• Spray Mancozeb 2 kg/ha in 15 days interval.
Disease cycle:
LATE BLIGHT
Phytopthora infestans
Symptoms:
• Water soaked lesions appears on edge of leaves
• Later it turns to large, brown patches with a green gray edge; not confined by major leaf veins.
• Infections progress through leaflets and petioles, resulting in large sections of brown foliage
• Lesions also girdle the Stem
• Dark brown, circular spots cover large parts of fruits, leading to dry brown rot
• In high humidity, thin powdery white fungal growth appears on infected leaves and stems.
• In cool, wet weather, entire fields turn brown and wilted
• Some time the plants look like stem without any single leaf.
• Symptoms also extended to tuber portion either in fields or during harvesting and storage.
• Brown discolorations are seen on the skin of the potato tuber followed by decaying and rotting of tubers
Etiology:
• The pathogen produces non-septate and hyaline mycelium.
• Sporangiophores emerge through the stomata on the lower surface singly or in groups.
• They are unbranched and bear single celled, hyaline, round or oval sporangia at the tip singly.
• The sporangia germinate to produce abundant zoospores.
• The fungus also produces oospores and chlamydospores in adverse seasons.
Favourable conditions:
T = 20-22°C, >90% RH, Cloudy days, Intermittent rains, Dense cropping, Poor drainage of soil
Management:
Page | 43
• Sanitation - Removal of infected plant debris i.e. infected leaves, shoots, tubers etc. from infested potato fields
• Proper drainage
• Selection of healthy seeds
• Avoid cutting of Tuber before planting
• 2-3 times deep summer ploughing during hot summer days followed by irrigation
• Crop rotation with non host crops i.e. beans, okra, cruciferous vegetables, cereals, oil seeds and pulses
• Do not allow field to field irigation specially from diseased fields to healthy fields
• Resistant cultivars – variety kufri Badsah, Kufri Naveen, Kufri Sinduri, Kufri Alankar, Kufri jawahar, Kufri Ashoka,
Kufri Anand, Kufri Giriraj and Kufri Jeevan
• Seed treatment with mancozeb
• Foliar application of Ridomil (0.1%)
• Soil application of Trichoderma bioformulation @ 25kg/ha
Disease cycle:
BLACK SCURF
Rhizoctonia solani
Symptom:
• Two type
• 1. Black Scurf
• 2. Stem Canker
• Raised, hard, black patches, irregular in size or shape, on the surface of the tuber.
• These are readily rubbed or scraped off
• Sunken, brown lesions develop on the sprouts before they emerge from the soil
• In severe cases the tip of the sprout is killed.
• often shoots again emerge from lower side, but emergence is delayed
• Rough, brown, sunken patches develop on the stem, below soil level
• If these girdle the stem then stunting and wilting often results, sometimes with the production of small, green,
aerial tubers in the junction between the stem and leaf stalk.
• Sanitation - Removal of infected plant debris i.e. infected leaves, shoots, tubers etc. from infested potato fields
• Proper drainage
• Selection of healthy seeds
• Avoid cutting of Tuber before planting
• 2-3 times deep summer ploughing during hot summer days followed by irrigation
• Crop rotation with non host crops i.e. beans, okra, cruciferous vegetables, cereals, oil seeds and pulses
• Do not allow field to field irigation specially from diseased fields to healthy fields
• Resistant cultivars – variety kufri Badsah, Kufri Naveen, Kufri Sinduri, Kufri Alankar, Kufri jawahar, Kufri Ashoka,
Kufri Anand, Kufri Giriraj and Kufri Jeevan
• Seed treatment with mancozeb
• Foliar application of Ridomil (0.1%)
• Soil application of Trichoderma bioformulation @ 25kg/ha
Disease cycle:
BLACK SCURF
Rhizoctonia solani
Symptom:
• Two type
• 1. Black Scurf
• 2. Stem Canker
• Raised, hard, black patches, irregular in size or shape, on the surface of the tuber.
• These are readily rubbed or scraped off
• Sunken, brown lesions develop on the sprouts before they emerge from the soil
• In severe cases the tip of the sprout is killed.
• often shoots again emerge from lower side, but emergence is delayed
• Rough, brown, sunken patches develop on the stem, below soil level
• If these girdle the stem then stunting and wilting often results, sometimes with the production of small, green,
aerial tubers in the junction between the stem and leaf stalk.
Page | 44
Etiology:
• Sub division: basidiomycotina
• Mycelium: septate, branched more or less at right angle, white when young and brown when old constricted
at the point of origin, multinucleate.
• Sclerotia: brown to black, uniform texture, more or less loosely packed, irregular in size, usually spherical.
Favourable conditions:
Soil temp.16-25 degree, above 25 degree reduces severity of diseases, acid soil is most favourable, more severe
in cool and moist soil.
Management:
• Disease free seed tubers should be planted.
• Shallow planting to avoid disease.
• Crop rotation for 2-3 years.
• Tuber treatment by boric acid @3%, dip for 25-30 min or Trichoderma 10g/lt for 10-15 min.
• Sanitation.
• Application of organic manure.
Disease cycle:
• The sclerotia on the seed tubers is the principal source of infection of the subsequent crop raised with tubers.
• On favourable conditions the mycelium present in soil may develop producing new hyphae.
LEAF ROLL
Potato leaf roll virus
Symptoms:
• Infection in the growing season occurs in the youngest leaves.
• A slight rolling and red/orange tinge can occur in the upper leaves.
• The bottom leaves may roll and the leaves becomes dry, brittle and papery
• The plant show a slight yellow and upturning of the upper leaves.
• Plant growth extremely reduced
• Death of growing points of plants
Etiology:
• Sub division: basidiomycotina
• Mycelium: septate, branched more or less at right angle, white when young and brown when old constricted
at the point of origin, multinucleate.
• Sclerotia: brown to black, uniform texture, more or less loosely packed, irregular in size, usually spherical.
Favourable conditions:
Soil temp.16-25 degree, above 25 degree reduces severity of diseases, acid soil is most favourable, more severe
in cool and moist soil.
Management:
• Disease free seed tubers should be planted.
• Shallow planting to avoid disease.
• Crop rotation for 2-3 years.
• Tuber treatment by boric acid @3%, dip for 25-30 min or Trichoderma 10g/lt for 10-15 min.
• Sanitation.
• Application of organic manure.
Disease cycle:
• The sclerotia on the seed tubers is the principal source of infection of the subsequent crop raised with tubers.
• On favourable conditions the mycelium present in soil may develop producing new hyphae.
LEAF ROLL
Potato leaf roll virus
Symptoms:
• Infection in the growing season occurs in the youngest leaves.
• A slight rolling and red/orange tinge can occur in the upper leaves.
• The bottom leaves may roll and the leaves becomes dry, brittle and papery
• The plant show a slight yellow and upturning of the upper leaves.
• Plant growth extremely reduced
• Death of growing points of plants
Page | 45
Etiology:
• Potato leafroll virus (PLRV)
• Genome – SS- RNA
• Protein coat – Spherical / Icosahedral
• Genus Polerovirus and Family Luteoviridae.
• This virus is transmitted by Aphid
Favourable conditions:
• Dense planting
• Insect vector
• Cloudy days
Management:
• use seed tubers from healthy plants or use certified seeds.
• Use resistant varieties.
• Monitor the field ,pick and destroy disease plants.
• Destroy weeds and volunteer plants that can host the virus and feed the aphids.
• Direct treatment of the virus is not possible,but reducing aphid population by means of predators of
parasitoids.
• Parasitic wasps could also be used.
• Apply insecticides in the early phase of crop growth.
• Crop rotation
Disease cycle:
MOSAIC
1- Mild mosaic - Potato virus X (PVX)
2- Super mild mosaic - Potato virus - A
3- Severe mosaic - Potato virus Y ( PVY)
4- Rugose mosaic of potato - Potato virus X and potato virus Y
Symptom:
• The disease is characterized by light and green mottling on the leaves
• The leaflets of affected leaves are usually distorted, puckered and smaller than normal.
• The affected plant appears stunted, pale green
Etiology:
• Potato leafroll virus (PLRV)
• Genome – SS- RNA
• Protein coat – Spherical / Icosahedral
• Genus Polerovirus and Family Luteoviridae.
• This virus is transmitted by Aphid
Favourable conditions:
• Dense planting
• Insect vector
• Cloudy days
Management:
• use seed tubers from healthy plants or use certified seeds.
• Use resistant varieties.
• Monitor the field ,pick and destroy disease plants.
• Destroy weeds and volunteer plants that can host the virus and feed the aphids.
• Direct treatment of the virus is not possible,but reducing aphid population by means of predators of
parasitoids.
• Parasitic wasps could also be used.
• Apply insecticides in the early phase of crop growth.
• Crop rotation
Disease cycle:
MOSAIC
1- Mild mosaic - Potato virus X (PVX)
2- Super mild mosaic - Potato virus - A
3- Severe mosaic - Potato virus Y ( PVY)
4- Rugose mosaic of potato - Potato virus X and potato virus Y
Symptom:
• The disease is characterized by light and green mottling on the leaves
• The leaflets of affected leaves are usually distorted, puckered and smaller than normal.
• The affected plant appears stunted, pale green
Page | 46
• Eye buds of the tubers are killed.
• Plants grown from infected tubers are stunted with brittle and crinkled leaves.
Etiology:
• Potato virus X (PVX)
• Genome – SS- RNA
• Protein coat – Flexious rod (640 × 12nm)
• Genus Potexvirus and Family Alfaflexiviridae.
• This virus is transmitted by Contact.
Favourable conditions:
20-30 ℃, High RH, Cloudy days
Management:
• Selection of tubers from the healthy field.
• Crop rotation with cereals and pulses.
• Removal of alternate and collateral host from the fields.
• Removal of infected tubers from the field.
• Rouging of infected plants just after the initiation of symptoms.
• Spray of Imidachloprid @ 0.3 ml/ l water for the control of insect vector.
• Detopping of the potato plants before maturity to check the spread of virus from foliage to tubers.
Disease cycle:
STRAWBERRY
LEAF SPOT:
Mycospharella fragarieae
Symptom:
• Symptoms appears on leaves fruits, berry caps, petioles, runners.
• Small, round, necrotic spots on strawberry leaves.
• Initially, these spots develop on upper leaf surface and are deep purple to red in color.
• The spots eventually develop tan, gray or almost white centres with distinct reddish purple to brown borders.
• During warm, humid weather, uniformly rusty brown spots without purple margins or light colored centres
may develop instead.
• Spots can occur on the undersides of the leaves as well, but these spots tend to be less vibrant in color.
• Eye buds of the tubers are killed.
• Plants grown from infected tubers are stunted with brittle and crinkled leaves.
Etiology:
• Potato virus X (PVX)
• Genome – SS- RNA
• Protein coat – Flexious rod (640 × 12nm)
• Genus Potexvirus and Family Alfaflexiviridae.
• This virus is transmitted by Contact.
Favourable conditions:
20-30 ℃, High RH, Cloudy days
Management:
• Selection of tubers from the healthy field.
• Crop rotation with cereals and pulses.
• Removal of alternate and collateral host from the fields.
• Removal of infected tubers from the field.
• Rouging of infected plants just after the initiation of symptoms.
• Spray of Imidachloprid @ 0.3 ml/ l water for the control of insect vector.
• Detopping of the potato plants before maturity to check the spread of virus from foliage to tubers.
Disease cycle:
STRAWBERRY
LEAF SPOT:
Mycospharella fragarieae
Symptom:
• Symptoms appears on leaves fruits, berry caps, petioles, runners.
• Small, round, necrotic spots on strawberry leaves.
• Initially, these spots develop on upper leaf surface and are deep purple to red in color.
• The spots eventually develop tan, gray or almost white centres with distinct reddish purple to brown borders.
• During warm, humid weather, uniformly rusty brown spots without purple margins or light colored centres
may develop instead.
• Spots can occur on the undersides of the leaves as well, but these spots tend to be less vibrant in color.
Page | 47
• As the disease progresses, spots enlarge and may merge together, in extreme cases leading to leaf death.
• Spots on berry, petioles, and runners resemble those produced on upper leaf surfaces.
• Shallow, black spots may develop on infected fruits, and are often surrounded by brown or black, leathery
tissue.
ETIOLOGY -
• Mycelium- septate, intercellular, branched
• Perithecia- dark brown to black, erumpent, ostiolate and size -46.8 x70.0µ in dia.
• Ascus-oblong, clavate, size- 28.8-36.8 x 8-10 μ.
• Ascospores- single septate, hyaline, ellipsoid, the upper cell slightly broader and measure 11-14.5 x 2-3 μ
• Conidia- elongated, olive brown, narrow, one septate, measure 14-45 x 2-3 μ.
FAVOURABLE CONDITION -
• High rainfall and warm temperatures are most favourable for this pathogen and lead to rapid disease
development.
• During mid to late spring, infections may be most severe due to frequent rain showers.
• The optimal temperature that will allow for most successful growth of the pathogen and development of
disease is around 25°C.
• The fungal pathogen favours 12 or more hours of leaf wetness for infection.
• New, young foliage has been found to be more susceptible to the pathogen when compared to mature,
developed foliage.
MANAGEMENT -
• Field sanitation
• Susceptible cultivars that should be avoided include Sparkle, Sunrise, Raritan and Catskill.
• Grow resistant varieties like 'Crimson King', 'Earliglow', 'Glooscap', 'Ogallala', and 'Ozark Beauty'.
• Remove the older and infected leaves from runner plants
• Take care in spacing runner plants in matted-row culture.
• Plant in light, well-drained soil in a location exposed to all-day sun and good air circulation.
• Control weeds in the planting. Weeds reduce air circulation and increase drying time for leaves. (Leaves stay
wet longer in weedy plantings.)
• Remove infected leaves after harvest
• Spraying of ferbam, Captan and benomyl 2g/lt, copper Oxy chloride (0.3%) or Carbendazim (0.1%)
• Spraying of micronutrients- manganese, copper and boron at the time of sprouting in the spring and during
budding.
DISEASE CYCLE -
• Fungus overwinters as mycelium, sclerotia, and perithecia in infected leaf tissues
• Spread - spores are spread by rain splash infecting new leaves as they emerge in the spring when conditions
are favourable
• Disease development is most successful in cool daytime temperatures and cold nighttime temperatures, high
relative humidity, and wet conditions.
• As the disease progresses, spots enlarge and may merge together, in extreme cases leading to leaf death.
• Spots on berry, petioles, and runners resemble those produced on upper leaf surfaces.
• Shallow, black spots may develop on infected fruits, and are often surrounded by brown or black, leathery
tissue.
ETIOLOGY -
• Mycelium- septate, intercellular, branched
• Perithecia- dark brown to black, erumpent, ostiolate and size -46.8 x70.0µ in dia.
• Ascus-oblong, clavate, size- 28.8-36.8 x 8-10 μ.
• Ascospores- single septate, hyaline, ellipsoid, the upper cell slightly broader and measure 11-14.5 x 2-3 μ
• Conidia- elongated, olive brown, narrow, one septate, measure 14-45 x 2-3 μ.
FAVOURABLE CONDITION -
• High rainfall and warm temperatures are most favourable for this pathogen and lead to rapid disease
development.
• During mid to late spring, infections may be most severe due to frequent rain showers.
• The optimal temperature that will allow for most successful growth of the pathogen and development of
disease is around 25°C.
• The fungal pathogen favours 12 or more hours of leaf wetness for infection.
• New, young foliage has been found to be more susceptible to the pathogen when compared to mature,
developed foliage.
MANAGEMENT -
• Field sanitation
• Susceptible cultivars that should be avoided include Sparkle, Sunrise, Raritan and Catskill.
• Grow resistant varieties like 'Crimson King', 'Earliglow', 'Glooscap', 'Ogallala', and 'Ozark Beauty'.
• Remove the older and infected leaves from runner plants
• Take care in spacing runner plants in matted-row culture.
• Plant in light, well-drained soil in a location exposed to all-day sun and good air circulation.
• Control weeds in the planting. Weeds reduce air circulation and increase drying time for leaves. (Leaves stay
wet longer in weedy plantings.)
• Remove infected leaves after harvest
• Spraying of ferbam, Captan and benomyl 2g/lt, copper Oxy chloride (0.3%) or Carbendazim (0.1%)
• Spraying of micronutrients- manganese, copper and boron at the time of sprouting in the spring and during
budding.
DISEASE CYCLE -
• Fungus overwinters as mycelium, sclerotia, and perithecia in infected leaf tissues
• Spread - spores are spread by rain splash infecting new leaves as they emerge in the spring when conditions
are favourable
• Disease development is most successful in cool daytime temperatures and cold nighttime temperatures, high
relative humidity, and wet conditions.
Page | 48
PEACH LEAF CURL
Taphrina deformans
Symptoms:
• The symptoms first appear in early spring.
• The leaves become twisted, thickened, puckered, curled downward and often distorted.
• In some leaves only a part of lamina are affected.
• In the beginning the affected leave are pale green or yellowish but finally they change to a reddish purple.
• On upper surface whitish fungal growth can be seen.
• Young shoot attached by fungus becomes twisted and distorted.
• Cause early defoliation and fruit drop.
Etiology:
• Sub-Division – Ascomycotina
• Family – Taphrinaceae
• Mycelium – Septate, branched and hyaline
• Asexual Spore – None
• Asexual fruiting body – None
• Sexual Spore – Ascospores (8) in Naked Asci
• Ascospores – Globose, unicellular
• Ascospores produce blastospore
Favourable conditions:
Temp- 16-20 degree,
high RH >80%,
wet leaf surface for at least 12 hours
Management:
• IDM
• Sanitation of Orchard
• Bordeaux mixture (6:6:50) or Copper oxychloride (0.25%)
• Chlorothalonil
• Organic manure
Disease cycle:
PEACH LEAF CURL
Taphrina deformans
Symptoms:
• The symptoms first appear in early spring.
• The leaves become twisted, thickened, puckered, curled downward and often distorted.
• In some leaves only a part of lamina are affected.
• In the beginning the affected leave are pale green or yellowish but finally they change to a reddish purple.
• On upper surface whitish fungal growth can be seen.
• Young shoot attached by fungus becomes twisted and distorted.
• Cause early defoliation and fruit drop.
Etiology:
• Sub-Division – Ascomycotina
• Family – Taphrinaceae
• Mycelium – Septate, branched and hyaline
• Asexual Spore – None
• Asexual fruiting body – None
• Sexual Spore – Ascospores (8) in Naked Asci
• Ascospores – Globose, unicellular
• Ascospores produce blastospore
Favourable conditions:
Temp- 16-20 degree,
high RH >80%,
wet leaf surface for at least 12 hours
Management:
• IDM
• Sanitation of Orchard
• Bordeaux mixture (6:6:50) or Copper oxychloride (0.25%)
• Chlorothalonil
• Organic manure
Disease cycle:
Page | 49
APPLE
SCAB
Ventura inaequalis
Symptom:
• The disease usually noticed on leaves and fruits.
• Affected leaves become twisted or puckered and have black, circular spots on their upper surface.
• On the under surface of leaves, the spots are velvety and may coalesce to cover the whole leaf surface.
• Severely affected leaves may turn yellow and drop.
• Scab can also infect flower stems and cause flowers to drop.
• The lesions later become sunken and brown and may have spores around their margins
• Infected fruit become distorted and may have cracks and rough surface.
Etiology:
• Sub-Division – Ascomycotina
• Class – Loculoascomycetes
• Mycelium -septate, branched
• Epidermal
• Asexual Spore - conidia ( formed in chain on conidiophores)
• Flame shaped, hyaline, 1-2 celled
• Conidiophore – Simple, unbranched, non-septate
• Sexual fruiting body – Pseudothecia
• Ascospore – oval to boat shaped, yellowish in color, 2 celled
Favourable conditions:
• 18-24 ℃ temperature
• Cool nights
• Wet surface
• >90% RH
Management:
• Sanitation
• Urea 5% spray
• Apply organic manure
• Cover soil near trunk (Spread a 3- to 6-inch layer of compost under trees)
• Hexaconazole, Penclonazole or Mancozeb
• (Avoid resistance development)
• BCA - Chaetomium globosum
• Choose resistant varieties when possible – Macfree, Freedom, Red free
APPLE
SCAB
Ventura inaequalis
Symptom:
• The disease usually noticed on leaves and fruits.
• Affected leaves become twisted or puckered and have black, circular spots on their upper surface.
• On the under surface of leaves, the spots are velvety and may coalesce to cover the whole leaf surface.
• Severely affected leaves may turn yellow and drop.
• Scab can also infect flower stems and cause flowers to drop.
• The lesions later become sunken and brown and may have spores around their margins
• Infected fruit become distorted and may have cracks and rough surface.
Etiology:
• Sub-Division – Ascomycotina
• Class – Loculoascomycetes
• Mycelium -septate, branched
• Epidermal
• Asexual Spore - conidia ( formed in chain on conidiophores)
• Flame shaped, hyaline, 1-2 celled
• Conidiophore – Simple, unbranched, non-septate
• Sexual fruiting body – Pseudothecia
• Ascospore – oval to boat shaped, yellowish in color, 2 celled
Favourable conditions:
• 18-24 ℃ temperature
• Cool nights
• Wet surface
• >90% RH
Management:
• Sanitation
• Urea 5% spray
• Apply organic manure
• Cover soil near trunk (Spread a 3- to 6-inch layer of compost under trees)
• Hexaconazole, Penclonazole or Mancozeb
• (Avoid resistance development)
• BCA - Chaetomium globosum
• Choose resistant varieties when possible – Macfree, Freedom, Red free
Page | 50
Disease cycle:
POWDERY MILDEW
Podosphaera lecotricha
Symptom:
• The infection usually starts as circular powdery white spots
• which can affect leaves, stems and sometimes fruits .
• It usually covers the upper parts of the leaves but may grow on the undersides as well.
• The fungus Hinders photosynthesis and cause the leaves turn yellow and dry out and some leaves might twist
, break or become disfigured .
• In the later stages the buds and growing tips become disfigured.
Etiology:
• Sub-Division – Ascomycotina
• Mycelium -septate, branched
• Superficial growth on host, establishing host relationship by haustoria.
• Asexual Spore - conidia ( formed in chain on conidiophores)
• Ellipsoidal to barrel shaped, hyaline, single celled
• Conidiophore – Simple, unbranched, non-septate
• Ceistothecia - closed structures having appendages (Straight, Bulbous base)
• Contain 1 Ascus
• Asci - broadly elliptic to sub globose
• Ascospores - Each ascus contains 8 ascospores
Favourable conditions: Powdery mildew infections occur when the relative humidity is grater than 70% and the
temperature between 20-25℃.
Management:
Disease cycle:
POWDERY MILDEW
Podosphaera lecotricha
Symptom:
• The infection usually starts as circular powdery white spots
• which can affect leaves, stems and sometimes fruits .
• It usually covers the upper parts of the leaves but may grow on the undersides as well.
• The fungus Hinders photosynthesis and cause the leaves turn yellow and dry out and some leaves might twist
, break or become disfigured .
• In the later stages the buds and growing tips become disfigured.
Etiology:
• Sub-Division – Ascomycotina
• Mycelium -septate, branched
• Superficial growth on host, establishing host relationship by haustoria.
• Asexual Spore - conidia ( formed in chain on conidiophores)
• Ellipsoidal to barrel shaped, hyaline, single celled
• Conidiophore – Simple, unbranched, non-septate
• Ceistothecia - closed structures having appendages (Straight, Bulbous base)
• Contain 1 Ascus
• Asci - broadly elliptic to sub globose
• Ascospores - Each ascus contains 8 ascospores
Favourable conditions: Powdery mildew infections occur when the relative humidity is grater than 70% and the
temperature between 20-25℃.
Management:
Page | 51
• use resistant or tolerant varieties – Red delicious, Golden delicious
• plant crops with sufficient spacing to allow for good air circulation.
• Monitor fields regularly to assess the incidence of a disease or pest.
• remove infected leaves when the first spots appear .
• a thick layer of mulch can prevent the dispersal of spores from the soil up onto the leaves.
• Chemical Control- ▪ Hexaconazole, Carbendazim, Karathane
• 5 Spray viz., 1. Green tip stage 2. Open cluster 3. Full pink stage 4. petal fall stage
• Biological Control-
Foliar sprays based on sulfer, neem oil, kodin or ascorbic acid can prevent severe infection
Spray 5% urea for early decomposition
Disease cycle:
FIRE BLIGHT OF APPLE
Erwinia amylovora
Symptom:
• Blossom Blight
• Shoot Blight
• Infected flowers appears water soaked and grey green, but soon become brown or black
• Petals of infected flowers fall off
• After few weeks of petal fall, symptom appear on young shoots
• The young leaves and stems turn brown to black, and finally wilt and fall off
• Cankers appear on the stems, tree trunk and even roots
• The infected branches are girdled and finally breaks
• Infection in root results in death of plants
• Oozing may be seen in the affected area
Etiology:
• Kingdom – Bacteria
• Gram stain – Negative
• use resistant or tolerant varieties – Red delicious, Golden delicious
• plant crops with sufficient spacing to allow for good air circulation.
• Monitor fields regularly to assess the incidence of a disease or pest.
• remove infected leaves when the first spots appear .
• a thick layer of mulch can prevent the dispersal of spores from the soil up onto the leaves.
• Chemical Control- ▪ Hexaconazole, Carbendazim, Karathane
• 5 Spray viz., 1. Green tip stage 2. Open cluster 3. Full pink stage 4. petal fall stage
• Biological Control-
Foliar sprays based on sulfer, neem oil, kodin or ascorbic acid can prevent severe infection
Spray 5% urea for early decomposition
Disease cycle:
FIRE BLIGHT OF APPLE
Erwinia amylovora
Symptom:
• Blossom Blight
• Shoot Blight
• Infected flowers appears water soaked and grey green, but soon become brown or black
• Petals of infected flowers fall off
• After few weeks of petal fall, symptom appear on young shoots
• The young leaves and stems turn brown to black, and finally wilt and fall off
• Cankers appear on the stems, tree trunk and even roots
• The infected branches are girdled and finally breaks
• Infection in root results in death of plants
• Oozing may be seen in the affected area
Etiology:
• Kingdom – Bacteria
• Gram stain – Negative
Page | 52
• Cell shape – Rod
• Flagella – Peritrichous
• Respiration – Aerobic
• Colony – Straw color to Yellowish and Diffused
Favourable conditions:
Temp. 20-22 degree, high RH >90%, rain, presence of pollinator
Management:
• IDM
• Sanitation
• Selection of a resistant cultivar Red Delicious and Golden Delicious
• Removal of expanding and overwintering cankers (Regular pruning)
• Application of Pseudomonas fluorescence
• Control sucking insects - Sucking insects create wounds through which fire blight bacteria can enter.
• Spray streptomycin at bloom -Streptomycin is an antibiotic that can kill fire blight bacteria before they enter
the apple tree.
Disease cycle:
• Survival: tree trunk
• PI: in flower, through nectorthods
• SI: bees, rain
• Flower to flower by bees
• Cell shape – Rod
• Flagella – Peritrichous
• Respiration – Aerobic
• Colony – Straw color to Yellowish and Diffused
Favourable conditions:
Temp. 20-22 degree, high RH >90%, rain, presence of pollinator
Management:
• IDM
• Sanitation
• Selection of a resistant cultivar Red Delicious and Golden Delicious
• Removal of expanding and overwintering cankers (Regular pruning)
• Application of Pseudomonas fluorescence
• Control sucking insects - Sucking insects create wounds through which fire blight bacteria can enter.
• Spray streptomycin at bloom -Streptomycin is an antibiotic that can kill fire blight bacteria before they enter
the apple tree.
Disease cycle:
• Survival: tree trunk
• PI: in flower, through nectorthods
• SI: bees, rain
• Flower to flower by bees
Page | 53
CROWN GALL
Agrobacterium tumefaciens
Symptom:
• The bacteria stimulate the tree to produce plant hormones that cause a tumor or gall to form.
• The galls most commonly occur on the roots or on the trunk near the soil line.
• At first, the galls appear light-colored and spongy.
• As the galls mature, they turn dark brown and woody
Etiology:
• Kingdom – Bacteria
• Family – Rhizobiaceae
• Gram stain – Negative
• Cell shape – Rod
• Flagella – Later
• Respiration – Aerobic
• Colony – White
Favourable conditions:
• 28-30 degree temprature Injury to plants
• Presence of moisture on the host surface
• susceptible variety
management:
• No cure exists for the disease, and it may kill a young apple tree by girdling the stem.
• A mature apple tree may be able to tolerate crown gall.
• Carefully inspect apple trees to avoid purchasing a tree infected with crown gall.
• If a recently planted tree develops crown gall, remove the tree and adjacent soil; the bacteria can persist for
several years in the soil.
• If your property has a history of crown gall infections, avoid planting fruit trees or other susceptible plants.
• When pruning, disinfect pruning tools between cuts. Use either a solution of 70% alcohol and 30% water, or a
10% bleach solution (1 part bleach with 9 parts water).
• Biological control: A non-pathogenic (non-disease causing) strain of the same bacterium (Agrobacterium
radiobacter strain 84) has been used to protect plants against infection by crown gall bacteria in the soil.
• Chemical control: the copper-based solutions refer to copper fungicides such as copper oxychloride, which
seems to show the best results of the copper compounds from my searches of the literature.
Disease cycle:
Crown gall is caused by a soil-borne bacterium that enters tree wounds caused by mower damage, pruning, frost cracks,
insects or planting damage.
CROWN GALL
Agrobacterium tumefaciens
Symptom:
• The bacteria stimulate the tree to produce plant hormones that cause a tumor or gall to form.
• The galls most commonly occur on the roots or on the trunk near the soil line.
• At first, the galls appear light-colored and spongy.
• As the galls mature, they turn dark brown and woody
Etiology:
• Kingdom – Bacteria
• Family – Rhizobiaceae
• Gram stain – Negative
• Cell shape – Rod
• Flagella – Later
• Respiration – Aerobic
• Colony – White
Favourable conditions:
• 28-30 degree temprature Injury to plants
• Presence of moisture on the host surface
• susceptible variety
management:
• No cure exists for the disease, and it may kill a young apple tree by girdling the stem.
• A mature apple tree may be able to tolerate crown gall.
• Carefully inspect apple trees to avoid purchasing a tree infected with crown gall.
• If a recently planted tree develops crown gall, remove the tree and adjacent soil; the bacteria can persist for
several years in the soil.
• If your property has a history of crown gall infections, avoid planting fruit trees or other susceptible plants.
• When pruning, disinfect pruning tools between cuts. Use either a solution of 70% alcohol and 30% water, or a
10% bleach solution (1 part bleach with 9 parts water).
• Biological control: A non-pathogenic (non-disease causing) strain of the same bacterium (Agrobacterium
radiobacter strain 84) has been used to protect plants against infection by crown gall bacteria in the soil.
• Chemical control: the copper-based solutions refer to copper fungicides such as copper oxychloride, which
seems to show the best results of the copper compounds from my searches of the literature.
Disease cycle:
Crown gall is caused by a soil-borne bacterium that enters tree wounds caused by mower damage, pruning, frost cracks,
insects or planting damage.
Page | 54
GRAPEVINE
DOWNY MILDEW
Plasmopara viticola
Symptom:
• Irregular yellowish translucent spots on the upper surface of the leaves.
• On lower side of spots downy (Cottony) growth of fungus can be seen
• Symptoms upper on all aerial and tender parts of the vine.
• Symptoms are more pronounced on leaves young shoots and immature berries.
• Infected leaves, shoots and tendrils are covered by whitish growth of the fungus.
• Dwarfing of tender shoots.
• No cracking of the skin of the berries.
Etiology:
• Sub-Division – Mastigomycotina
• Family – Perenosporaceae
• Mycelium : Hyaline, coenocytic, intercellular with knob shaped haustoria, branched.
• Sporangiophores : branching @ right angles to the axis
• Sporangia : Hyaline, single celled, lemon shaped, Produce zoospore after germination
• Zoospore : Biflagellate
• Oospore : Simple, double thick walled, spherical, 28-40 μm in diameter.
Favourable conditions:
• The most favourable temperature for germination of Sporangia is between 10 – 23 0C
• Relative humidity is above 80%
• Temperature is 23 and 27 0C
Management:
• Regulatory measures
Restriction on the movement of planting material at regional, national or international level should be
imposed, since the pathogen spread through dormant cuttings.
• Cultural practice
Sanitation
All infected plant material and pruned parts must be removed and burnt before bud sprouting, so as to reduce
primary inoculum.
Well drained soil
Good air movement
• Biological control
Erwinia herbicola, a saprophytic bacterium, used as liquid culture and sprayed on vines which inhibits P. viticola
upto 75%.
• Chemical control
5 Spray of Chemicals like
Foestly aluminium 0.2% or Metalaxyl 0.2% or Copper oxychloride are effective
At
1. Just after pruning
2. 3-4 week after pruning
3. Before buds open
4. When berries has formed
GRAPEVINE
DOWNY MILDEW
Plasmopara viticola
Symptom:
• Irregular yellowish translucent spots on the upper surface of the leaves.
• On lower side of spots downy (Cottony) growth of fungus can be seen
• Symptoms upper on all aerial and tender parts of the vine.
• Symptoms are more pronounced on leaves young shoots and immature berries.
• Infected leaves, shoots and tendrils are covered by whitish growth of the fungus.
• Dwarfing of tender shoots.
• No cracking of the skin of the berries.
Etiology:
• Sub-Division – Mastigomycotina
• Family – Perenosporaceae
• Mycelium : Hyaline, coenocytic, intercellular with knob shaped haustoria, branched.
• Sporangiophores : branching @ right angles to the axis
• Sporangia : Hyaline, single celled, lemon shaped, Produce zoospore after germination
• Zoospore : Biflagellate
• Oospore : Simple, double thick walled, spherical, 28-40 μm in diameter.
Favourable conditions:
• The most favourable temperature for germination of Sporangia is between 10 – 23 0C
• Relative humidity is above 80%
• Temperature is 23 and 27 0C
Management:
• Regulatory measures
Restriction on the movement of planting material at regional, national or international level should be
imposed, since the pathogen spread through dormant cuttings.
• Cultural practice
Sanitation
All infected plant material and pruned parts must be removed and burnt before bud sprouting, so as to reduce
primary inoculum.
Well drained soil
Good air movement
• Biological control
Erwinia herbicola, a saprophytic bacterium, used as liquid culture and sprayed on vines which inhibits P. viticola
upto 75%.
• Chemical control
5 Spray of Chemicals like
Foestly aluminium 0.2% or Metalaxyl 0.2% or Copper oxychloride are effective
At
1. Just after pruning
2. 3-4 week after pruning
3. Before buds open
4. When berries has formed
Page | 55
5. During growth of shoot
Disease cycle:
• Survival – Oospore + Mycelium in Infected debris and Infected parts
• PI - The primary infection of the disease is initiated from the oospores.
• Secondary spread - sporangia and zoospores, which are formed on the new shoots.
POWDERY MILDEW
Uncinula necator
Symptoms:
• The disease attacks vines at any stage of growth.
• All the aerial parts of the plant are attacked.
• Cluster and berry infections usually appear first
• Powdery growth is visible on older berries and the infection results in the cracking of skin of the berries.
• Powdery growth mostly on the upper surface of the leaves
• Infection of stem leads to dark brown discoloration
• Floral infection results in shedding of flowers and poor fruit set
• Early berry infection results in shedding of affected berries
Etiology:
• Sub-Division – Ascomycotina
• Class – Pyrenomycetes
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia
• Asexual fruiting body – Naked
• Conidiophore - Simple, vertical, unbranched
• Sexual Spore – Ascospore – Single celled
• sexual fruiting body – Cleistotheci
• Cleistothecia – closed fruiting body, Circinate appendages
Favourable conditions:
• Cool dry weather
5. During growth of shoot
Disease cycle:
• Survival – Oospore + Mycelium in Infected debris and Infected parts
• PI - The primary infection of the disease is initiated from the oospores.
• Secondary spread - sporangia and zoospores, which are formed on the new shoots.
POWDERY MILDEW
Uncinula necator
Symptoms:
• The disease attacks vines at any stage of growth.
• All the aerial parts of the plant are attacked.
• Cluster and berry infections usually appear first
• Powdery growth is visible on older berries and the infection results in the cracking of skin of the berries.
• Powdery growth mostly on the upper surface of the leaves
• Infection of stem leads to dark brown discoloration
• Floral infection results in shedding of flowers and poor fruit set
• Early berry infection results in shedding of affected berries
Etiology:
• Sub-Division – Ascomycotina
• Class – Pyrenomycetes
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia
• Asexual fruiting body – Naked
• Conidiophore - Simple, vertical, unbranched
• Sexual Spore – Ascospore – Single celled
• sexual fruiting body – Cleistotheci
• Cleistothecia – closed fruiting body, Circinate appendages
Favourable conditions:
• Cool dry weather
Page | 56
• Temperature in the range of 21-30 ℃
• R.H. 40-100%
• Most incidence (November and December)
Management:
• Clean cultivation of vines or removal and destruction of all diseased parts
• Grow resistant varieties like Black Prince, Sultana Red, Skibba Red, Skibba White
• Spray NSKE 5% or Neem oil 3% twice at 10 days interval from initial disease appearance.
• Spray Eucalyptus leaf extract 10% at initiation of the disease and 10 days later.
• Spray Carbendazim 500 g or wettable sulphur 1500g/ha or Propiconazole 500 ml/ha or Karathane at initiation
of the disease and 10 days later
• Three spray of Chemical (S Dust or wettable sulphur)
1 st – when shoots are 3-4 inch height
2 nd – at flowering stage
3 rd – after 2 month
Disease cycle:
• Primary Infection:
Through dormant mycelium and conidia present in the infected shoots and buds
• Secondary Infection:
Through air-borne conidia
ANTHRACNOSE
Telomorph - Elsinoe ampelina
Anamorph - Sphaceloma ampelinum
Symptom:
The fungus attacks shoots, tendrils, petioles, leaves, stems and also the inflorescence and berries.
Leaves :-
• Temperature in the range of 21-30 ℃
• R.H. 40-100%
• Most incidence (November and December)
Management:
• Clean cultivation of vines or removal and destruction of all diseased parts
• Grow resistant varieties like Black Prince, Sultana Red, Skibba Red, Skibba White
• Spray NSKE 5% or Neem oil 3% twice at 10 days interval from initial disease appearance.
• Spray Eucalyptus leaf extract 10% at initiation of the disease and 10 days later.
• Spray Carbendazim 500 g or wettable sulphur 1500g/ha or Propiconazole 500 ml/ha or Karathane at initiation
of the disease and 10 days later
• Three spray of Chemical (S Dust or wettable sulphur)
1 st – when shoots are 3-4 inch height
2 nd – at flowering stage
3 rd – after 2 month
Disease cycle:
• Primary Infection:
Through dormant mycelium and conidia present in the infected shoots and buds
• Secondary Infection:
Through air-borne conidia
ANTHRACNOSE
Telomorph - Elsinoe ampelina
Anamorph - Sphaceloma ampelinum
Symptom:
The fungus attacks shoots, tendrils, petioles, leaves, stems and also the inflorescence and berries.
Leaves :-
Page | 57
• mall, irregular, dark brown spots.
• The central tissue turn grey and falls.
• Spots on petioles and leaves cause them to curl or become distorted.
• The spots are 7mm in diameter
Shoots :-
• Numerous spets occur on young shoots.
• These spots may unite to girdle the stem and cause death of the tips and may also cause die-back symptoms.
Berries :-
• Characteristic round, brown sunken spots resembling "Birds Eye" appear and hence the name of the disease.
• The symptom appears as dark red spots on the berry.
Favourable conditions:
• Maximum temperature in the range of 27-31 °C.
• Relative humidity 90-100%.
• Warm wet weather with continuous drizzle of rain and
• windy weather for 2-3 days
• Low lying and ill drained soils
• Susceptible variety.
• Heavy rains after pruning
Management:
• Cultural Management –
All cankerous vines should be pruned and burnt to remove primary inoculum.
Training of vines should be done in a manner that water splashes should not reach the foliage and branches
during rainy season.
Ground level branches should be removed.
• Biological Management -
Trichoderma spp. is used as a biological control agent.
• Varietal Resistance Varieties like Banglore blue, Golden Muscat, Golden queen and Isabella are resistant
• Quarantine Management -
If area is disease free, restrict the entry of planting material from infected to healthy area.
• Chemical Management
Spray vineyards at the time of leaf emergence with benomyl (0.1%), carbendazim (0.1%), or Bordeaux mixture
(1.0%).
At least four sprays of fungicides should be given during rainy season at fortnightly intervals.
Disease cycle:
Survival - pathogen survives in stems and infected twigs
PI - Through dormant mycelium, conidia and Pseudothecia present in infected shoots and buds.
Secondary spread - through conidia which are carried by wind and rain water
• mall, irregular, dark brown spots.
• The central tissue turn grey and falls.
• Spots on petioles and leaves cause them to curl or become distorted.
• The spots are 7mm in diameter
Shoots :-
• Numerous spets occur on young shoots.
• These spots may unite to girdle the stem and cause death of the tips and may also cause die-back symptoms.
Berries :-
• Characteristic round, brown sunken spots resembling "Birds Eye" appear and hence the name of the disease.
• The symptom appears as dark red spots on the berry.
Favourable conditions:
• Maximum temperature in the range of 27-31 °C.
• Relative humidity 90-100%.
• Warm wet weather with continuous drizzle of rain and
• windy weather for 2-3 days
• Low lying and ill drained soils
• Susceptible variety.
• Heavy rains after pruning
Management:
• Cultural Management –
All cankerous vines should be pruned and burnt to remove primary inoculum.
Training of vines should be done in a manner that water splashes should not reach the foliage and branches
during rainy season.
Ground level branches should be removed.
• Biological Management -
Trichoderma spp. is used as a biological control agent.
• Varietal Resistance Varieties like Banglore blue, Golden Muscat, Golden queen and Isabella are resistant
• Quarantine Management -
If area is disease free, restrict the entry of planting material from infected to healthy area.
• Chemical Management
Spray vineyards at the time of leaf emergence with benomyl (0.1%), carbendazim (0.1%), or Bordeaux mixture
(1.0%).
At least four sprays of fungicides should be given during rainy season at fortnightly intervals.
Disease cycle:
Survival - pathogen survives in stems and infected twigs
PI - Through dormant mycelium, conidia and Pseudothecia present in infected shoots and buds.
Secondary spread - through conidia which are carried by wind and rain water
Page | 58
CITRUS
CANKER
Xanthomonas campestris pv. Citri
Symptom:
• Symptoms appears on leaves, stems and fruits.
• Acid lime, lemon and grapefruit are affected.
• Rare on sweet oranges and mandarins.
• Leaves - Initially water soaked spots appear which slowly turn brown and produce corky raised spots and falls
• Followed by development of yellow hallow.
• Stem –
• Same as on leaves but yellow hallow is absent,
• bark eruption takes place and, bacteria oozing out during warm rainy season from cracks.
• Finally stem girdled and die.
• Fruits –
• Brownish corky out growth with cracks and crater like appearance at a later stage is the common symptom.
• On fruits, canker lesions appears which reduces the marketing quality.
• Fruits become less juicy
Etiology:
• Kingdom – Bacteria
• Gram stain – Negative
• Cell shape – Rod
• Flagella – Monotrichous
• Respiration – Aerobic
• Colony – Straw color to Yellowish and Diffused
Favourable conditions:
• 20-30 °C temperature
• high relative humidity (90%)
• Presence of moisture on the host surface
• Susceptible variety
• Infestation of Leaf minor larvae
Management:
• Cultural Management –
Infected leaves, stem, fruit etc should be removed and Burnt
Grow Resistant varieties Citron, Calmondin
Prune badly infected twigs before the on set off monsoon.
• Quarantine Management –
If area is disease free, restrict the entry of planting material from infected area.
• Physical Management –
Hot water treatment of root stocks at 50°C for 10-15 minutes.
• Biological Management –
CITRUS
CANKER
Xanthomonas campestris pv. Citri
Symptom:
• Symptoms appears on leaves, stems and fruits.
• Acid lime, lemon and grapefruit are affected.
• Rare on sweet oranges and mandarins.
• Leaves - Initially water soaked spots appear which slowly turn brown and produce corky raised spots and falls
• Followed by development of yellow hallow.
• Stem –
• Same as on leaves but yellow hallow is absent,
• bark eruption takes place and, bacteria oozing out during warm rainy season from cracks.
• Finally stem girdled and die.
• Fruits –
• Brownish corky out growth with cracks and crater like appearance at a later stage is the common symptom.
• On fruits, canker lesions appears which reduces the marketing quality.
• Fruits become less juicy
Etiology:
• Kingdom – Bacteria
• Gram stain – Negative
• Cell shape – Rod
• Flagella – Monotrichous
• Respiration – Aerobic
• Colony – Straw color to Yellowish and Diffused
Favourable conditions:
• 20-30 °C temperature
• high relative humidity (90%)
• Presence of moisture on the host surface
• Susceptible variety
• Infestation of Leaf minor larvae
Management:
• Cultural Management –
Infected leaves, stem, fruit etc should be removed and Burnt
Grow Resistant varieties Citron, Calmondin
Prune badly infected twigs before the on set off monsoon.
• Quarantine Management –
If area is disease free, restrict the entry of planting material from infected area.
• Physical Management –
Hot water treatment of root stocks at 50°C for 10-15 minutes.
• Biological Management –
Page | 59
Pseudomonas fluorescence suspension can be sprayed as biological control agent.
• Chemical Management –
Spray Streptocycline sulphate 500-1000 ppm; or or Copper oxychloride 0.2% at fortnight intervals on the plant
Control leaf miner when young flush is produced
Disease cycle:
• Survival :- pathogen survives in infected leaves for 6 months .
• PI :- the diseased twigs ( stems ) and leaves are the main source of inoculum.
• The bacterium enters the host through stomata, Lenticle or wounds.
• Secondary spread through wind, rain and insects.
CITRUS GUMMOSIS
Phytophthora nicotianae var. parasitica, p. palmivora, p.citrophthora
Symptom:
• Disease starts as water soaked large patches on the basal portions of the stem near the ground level.
• Bark in such parts dries, shrinks and cracks and shreds in lengthwise vertical strips.
• Later profuse exudation of gum from the bark of the trunk occurs.
• Considerable amount of gum formation in sweet oranges may be observed, but relatively little in grapefruit.
• Affected collar region is girdled and finally the infected tree dies
Etiology:
• The pathogen produces non-septate and hyaline mycelium.
• Sporangiophores -They are unbranched and bear single celled, hyaline, round or oval sporangia at the tip singly.
• The sporangia germinate to produce abundant zoospores
• The fungus also produces oospores and chlamydospores in adverse seasons.
Favourable conditions:
• The Phytophthora species causing gummosis develop rapidly under moist and cool conditions.
• Prolonged direct contact of trunk with water, as in flood irrigation and water
• logging predisposes trees to disease
• Incidence is more in black soils than in light soils
• High water table leads to high incidence
• The disease is severe in high rainfall areas
• Low budded grafts are mostly affected
Pseudomonas fluorescence suspension can be sprayed as biological control agent.
• Chemical Management –
Spray Streptocycline sulphate 500-1000 ppm; or or Copper oxychloride 0.2% at fortnight intervals on the plant
Control leaf miner when young flush is produced
Disease cycle:
• Survival :- pathogen survives in infected leaves for 6 months .
• PI :- the diseased twigs ( stems ) and leaves are the main source of inoculum.
• The bacterium enters the host through stomata, Lenticle or wounds.
• Secondary spread through wind, rain and insects.
CITRUS GUMMOSIS
Phytophthora nicotianae var. parasitica, p. palmivora, p.citrophthora
Symptom:
• Disease starts as water soaked large patches on the basal portions of the stem near the ground level.
• Bark in such parts dries, shrinks and cracks and shreds in lengthwise vertical strips.
• Later profuse exudation of gum from the bark of the trunk occurs.
• Considerable amount of gum formation in sweet oranges may be observed, but relatively little in grapefruit.
• Affected collar region is girdled and finally the infected tree dies
Etiology:
• The pathogen produces non-septate and hyaline mycelium.
• Sporangiophores -They are unbranched and bear single celled, hyaline, round or oval sporangia at the tip singly.
• The sporangia germinate to produce abundant zoospores
• The fungus also produces oospores and chlamydospores in adverse seasons.
Favourable conditions:
• The Phytophthora species causing gummosis develop rapidly under moist and cool conditions.
• Prolonged direct contact of trunk with water, as in flood irrigation and water
• logging predisposes trees to disease
• Incidence is more in black soils than in light soils
• High water table leads to high incidence
• The disease is severe in high rainfall areas
• Low budded grafts are mostly affected
Page | 60
Management:
• Always keep the orchard clean.
• Prune unproductive, dry and disease/ insect infected branches
• Use Bordeaux paste on wounds created by pruning and on the main trunk from the ground well to about one
meter high.
• Spray bordeaux mixture 1% thoroughly on the whole plant after harvest and repeat again at fruit setting.
• Monitor the orchard regularly.
• Soil drenching with 0.2% Metalaxyl (Metalaxyl+Mancozeb = Ridomil MZ 72)
• Apply Trichoderma viride multiplied on neem cake
• Following Double ring method of irrigation by providing an inner ring about 45 cm around the tree trunk to
prevent direct moistening of trunk’
• Avoid injuries to crown roots or base of stem during cultural operations
• Use resistant sour orange or trifoliate orange rootstocks for propagating popular/commercial varieties.
Disease cycle:
PI: oospores or as dormant mycelium
SI: sporangia and zoospores spread by splashing rain and irrigation water.
MANGO
ANTHRACNOSE
Colletotrichum gloeosporioides
Symptoms:
Management:
• Always keep the orchard clean.
• Prune unproductive, dry and disease/ insect infected branches
• Use Bordeaux paste on wounds created by pruning and on the main trunk from the ground well to about one
meter high.
• Spray bordeaux mixture 1% thoroughly on the whole plant after harvest and repeat again at fruit setting.
• Monitor the orchard regularly.
• Soil drenching with 0.2% Metalaxyl (Metalaxyl+Mancozeb = Ridomil MZ 72)
• Apply Trichoderma viride multiplied on neem cake
• Following Double ring method of irrigation by providing an inner ring about 45 cm around the tree trunk to
prevent direct moistening of trunk’
• Avoid injuries to crown roots or base of stem during cultural operations
• Use resistant sour orange or trifoliate orange rootstocks for propagating popular/commercial varieties.
Disease cycle:
PI: oospores or as dormant mycelium
SI: sporangia and zoospores spread by splashing rain and irrigation water.
MANGO
ANTHRACNOSE
Colletotrichum gloeosporioides
Symptoms:
Page | 61
• Produces leaf spots, blossom blight, wither tip, twigs blight and fruit rot.
• Small blister like spots develop on the leaves and twigs.
• Large number of spots appears in leaves, coalesce to each other and cover major portion of leaf lamina
• Young leaves wither and dry.
• Tender twigs wither and die back symptom appears.
• Affected branches ultimately dry up.
• Black spots appear on fruits.
• The fruit pulp becomes hard, crack and decay at ripening. Infected fruits drop
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and Dark
• The mycelium of the fungus is localized in the spot.
• Asexual Spore – Conidia - hyaline, single celled and falcate in shape.
• Asexual fruiting body – Acervullus
• Acervuli with setae arise through epidermis
• Sexual fruiting body – Perithecia – Pear shaped, In Leaf sheath
• Also produce Chlamydospore
• Colony colour – Black
Favourable conditions:
• 25-30 ℃, High RH, Presence of free water, Dense planting, Shadow
Management:
• Removal of infected buds, twigs, leaf from the orchard.
• Pruning and cutting of heavily infected inflorescence twig.
• Spraying of copper oxychloride, mancozeb @ 0.25 to 3 % at an interval of 7- 10 days starting from the rainy
season.
• Before storage ripen fruits should be treated in hot water at 50 ℃ for 15 minutes or dip in Benomyl solution
(500 ppm) or Thiobendazole (1000 ppm) for 5 minutes
• Avoid over-crowding in orchards
• Removal of fallen leaves.
Disease cycle:
Mango malformation
Fusarium moniliforme var. subglutinans
• Produces leaf spots, blossom blight, wither tip, twigs blight and fruit rot.
• Small blister like spots develop on the leaves and twigs.
• Large number of spots appears in leaves, coalesce to each other and cover major portion of leaf lamina
• Young leaves wither and dry.
• Tender twigs wither and die back symptom appears.
• Affected branches ultimately dry up.
• Black spots appear on fruits.
• The fruit pulp becomes hard, crack and decay at ripening. Infected fruits drop
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and Dark
• The mycelium of the fungus is localized in the spot.
• Asexual Spore – Conidia - hyaline, single celled and falcate in shape.
• Asexual fruiting body – Acervullus
• Acervuli with setae arise through epidermis
• Sexual fruiting body – Perithecia – Pear shaped, In Leaf sheath
• Also produce Chlamydospore
• Colony colour – Black
Favourable conditions:
• 25-30 ℃, High RH, Presence of free water, Dense planting, Shadow
Management:
• Removal of infected buds, twigs, leaf from the orchard.
• Pruning and cutting of heavily infected inflorescence twig.
• Spraying of copper oxychloride, mancozeb @ 0.25 to 3 % at an interval of 7- 10 days starting from the rainy
season.
• Before storage ripen fruits should be treated in hot water at 50 ℃ for 15 minutes or dip in Benomyl solution
(500 ppm) or Thiobendazole (1000 ppm) for 5 minutes
• Avoid over-crowding in orchards
• Removal of fallen leaves.
Disease cycle:
Mango malformation
Fusarium moniliforme var. subglutinans
Page | 62
Fusarium magiferae
Symptoms:
• 2 types of symptoms viz., floral and vegetative malformation
• Vegetative Malformation (VM) is more commonly found on young seedlings.
• The seedlings produce small shootlets bearing small scaly leaves with a bunch like appearance on the shoot
apex.
• Seedling remains stunted and die while those getting infected later resume normal growth.
• Floral malformation (FM) is the malformation of panicles.
• The severity of malformation may vary on the same shoot from light to medium or heavy malformation of
panicles.
• Heavily malformed panicles are compact and overcrowded due to larger flowers.
• male and hermaphrodite flowers that are either sterile or eventually abort
• They continue to grow and remain as black masses of dry tissue during summer but some of them continue to
grow till the next season.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia
• Asexual fruiting body – Sporodochia
• Conidia – 1. macro conidia – boat shaped, hyaline, long, septate, pointed at tip 2. micro conidia – small, curved,
unicellular ▪ Conidiophore – simple, slender, short, produced in sporodochium.
Favourable condition:
• Temp. 20-25 degree c
• High RH>80%
• Mite infestation
Management:
• IDM
• Diseased plants should be destroyed. Use disease free planting material
• Scion sticks from infected trees should not be used.
• As soon as the disease appears, the affected terminals along with the basal 15-20 cm healthy portion should
be removed or pruned and burnt.
• If more than 25 per cent affected plants, de-blossoming at bud burst stage should be done to delay the
flowering.
• Spraying of Planofix (200 ppm) during the first week of October followed by deblossoming at bud burst stage
is recommended.
• A single foliar application of 1,000 ppm cobalt sulphate prior to flower bud differentiation successfully reduce
the floral malformation.
• Prochloraz sprays (0.1% concentration)
• This is followed by the spraying of Carbendazim (0.1%) or Captafol (0.2%).
Disease cycle:
Fusarium magiferae
Symptoms:
• 2 types of symptoms viz., floral and vegetative malformation
• Vegetative Malformation (VM) is more commonly found on young seedlings.
• The seedlings produce small shootlets bearing small scaly leaves with a bunch like appearance on the shoot
apex.
• Seedling remains stunted and die while those getting infected later resume normal growth.
• Floral malformation (FM) is the malformation of panicles.
• The severity of malformation may vary on the same shoot from light to medium or heavy malformation of
panicles.
• Heavily malformed panicles are compact and overcrowded due to larger flowers.
• male and hermaphrodite flowers that are either sterile or eventually abort
• They continue to grow and remain as black masses of dry tissue during summer but some of them continue to
grow till the next season.
Etiology:
• Sub-Division – Deuteromycotina
• Mycelium – Septate, branched and hyaline
• Asexual Spore – Conidia
• Asexual fruiting body – Sporodochia
• Conidia – 1. macro conidia – boat shaped, hyaline, long, septate, pointed at tip 2. micro conidia – small, curved,
unicellular ▪ Conidiophore – simple, slender, short, produced in sporodochium.
Favourable condition:
• Temp. 20-25 degree c
• High RH>80%
• Mite infestation
Management:
• IDM
• Diseased plants should be destroyed. Use disease free planting material
• Scion sticks from infected trees should not be used.
• As soon as the disease appears, the affected terminals along with the basal 15-20 cm healthy portion should
be removed or pruned and burnt.
• If more than 25 per cent affected plants, de-blossoming at bud burst stage should be done to delay the
flowering.
• Spraying of Planofix (200 ppm) during the first week of October followed by deblossoming at bud burst stage
is recommended.
• A single foliar application of 1,000 ppm cobalt sulphate prior to flower bud differentiation successfully reduce
the floral malformation.
• Prochloraz sprays (0.1% concentration)
• This is followed by the spraying of Carbendazim (0.1%) or Captafol (0.2%).
Disease cycle:
Page | 63
Bacterial blight of mango
Bacterial Spot or Bacterial Black spot or Bacterial Canker
Xanthomonas campestris pv mangiferaeindicae
Symptoms:
• The disease is noticed on leaves, leaf stalks, stems, twigs, branches and fruits
• Initially producing water soaked lesions
• later turning into irregular to angular raised lesions measuring 1-4 mm in diameter are formed.
• These lesions are light yellow in colour, initially with yellow halo but with age enlarge or coalesce to form
irregular necrotic cankerous patches with dark brown colour.
• On fruits, water-soaked, dark brown to black coloured lesions are observed which gradually developed into
cankerous, raised or flat spots.
• These spots grow bigger usually up to 1 to 5 mm in diameter, coalesce to each other and covers almost the
whole fruit.
• These spots often, burst extruding gummy substances containing highly contagious bacterial cells.
Etiology:
• Xanthomonas campestris pv mangiferaeindicae
• Kingdom – Bacteria
• Gram stain – Negative
• Cell shape – Rod
• Flagella – Monotrichous
• Respiration – Aerobic
• Colony – Straw color to Yellowish and Diffused
Favourable conditions:
20-30 °C temperature, high relative humidity (90%), Presence of moisture on the host surface, Susceptible
variety, Mechanical injury
Management:
• Use healthy planting and grafting material.
• Disinfect working tools and equipment.
• Use resistant varieties if available
• Ensure good ventilation of the trees.
• Regularly remove infected twigs, branches and fruits.
• Avoid mechanical damage to the mango trees during field work.
• Protect them from strong winds and heavy rains with windbreaks.
• Infected fruits and tree material should be destroyed
• Spray Copper oxy chlorite at 15 days intervals
• Collect fallen leaves and destroy
Bacterial blight of mango
Bacterial Spot or Bacterial Black spot or Bacterial Canker
Xanthomonas campestris pv mangiferaeindicae
Symptoms:
• The disease is noticed on leaves, leaf stalks, stems, twigs, branches and fruits
• Initially producing water soaked lesions
• later turning into irregular to angular raised lesions measuring 1-4 mm in diameter are formed.
• These lesions are light yellow in colour, initially with yellow halo but with age enlarge or coalesce to form
irregular necrotic cankerous patches with dark brown colour.
• On fruits, water-soaked, dark brown to black coloured lesions are observed which gradually developed into
cankerous, raised or flat spots.
• These spots grow bigger usually up to 1 to 5 mm in diameter, coalesce to each other and covers almost the
whole fruit.
• These spots often, burst extruding gummy substances containing highly contagious bacterial cells.
Etiology:
• Xanthomonas campestris pv mangiferaeindicae
• Kingdom – Bacteria
• Gram stain – Negative
• Cell shape – Rod
• Flagella – Monotrichous
• Respiration – Aerobic
• Colony – Straw color to Yellowish and Diffused
Favourable conditions:
20-30 °C temperature, high relative humidity (90%), Presence of moisture on the host surface, Susceptible
variety, Mechanical injury
Management:
• Use healthy planting and grafting material.
• Disinfect working tools and equipment.
• Use resistant varieties if available
• Ensure good ventilation of the trees.
• Regularly remove infected twigs, branches and fruits.
• Avoid mechanical damage to the mango trees during field work.
• Protect them from strong winds and heavy rains with windbreaks.
• Infected fruits and tree material should be destroyed
• Spray Copper oxy chlorite at 15 days intervals
• Collect fallen leaves and destroy
Page | 64
• Apply Pseudomonas BCA
• Apply proper nutrient , organic manure
• Avoid sprinkler irrigation
• Proper spacing
Disease cycle:
POWDERY MILDEW
Oidium mangiferae
Symptoms:
• Disease mostly appear in February March
• Symptoms appears on leaves, stalks of panicles, flowers and young fruits
• Small, powdery white patches appears on leaves
• Later it enlarge and cover entire leaf lamina
• Fungus can also grow on stalks of panicles, flowers and young fruits
• The affected flowers and fruits drop pre-maturely reducing the fruit set.
• Often these patches coalesce and occupy larger areas turning into purplish brown in colour
Etiology:
• Sub-Division – Ascomycotina
• Mycelium -septate, branched
• Superficial growth on host, establishing host relationship by haustoria.
• Asexual Spore - conidia ( formed in chain on conidiophores)
• Ellipsoidal to barrel shaped, hyaline, single celled
• Conidiophore – Simple, unbranched, non-septate
• Ceistothecia – None
• Asci – None
• Ascospores – None
Favourable conditions:
Cloudy weather, Heavy moisture, Morning mist, 20-25℃, 70% RH max spore germination
• Apply Pseudomonas BCA
• Apply proper nutrient , organic manure
• Avoid sprinkler irrigation
• Proper spacing
Disease cycle:
POWDERY MILDEW
Oidium mangiferae
Symptoms:
• Disease mostly appear in February March
• Symptoms appears on leaves, stalks of panicles, flowers and young fruits
• Small, powdery white patches appears on leaves
• Later it enlarge and cover entire leaf lamina
• Fungus can also grow on stalks of panicles, flowers and young fruits
• The affected flowers and fruits drop pre-maturely reducing the fruit set.
• Often these patches coalesce and occupy larger areas turning into purplish brown in colour
Etiology:
• Sub-Division – Ascomycotina
• Mycelium -septate, branched
• Superficial growth on host, establishing host relationship by haustoria.
• Asexual Spore - conidia ( formed in chain on conidiophores)
• Ellipsoidal to barrel shaped, hyaline, single celled
• Conidiophore – Simple, unbranched, non-septate
• Ceistothecia – None
• Asci – None
• Ascospores – None
Favourable conditions:
Cloudy weather, Heavy moisture, Morning mist, 20-25℃, 70% RH max spore germination
Page | 65
Management:
• No resistant variety is available
• Chemical spray during flowering , fruit set
• Topsin , Karathane , Bordedaux mixture
• Carbendazim, Hexaconazole
• Sanitation
• Destroy crop residue
• Proper nutrient application
• Sulphur spray
• Spray of 5% urea in fallen leaves for early decomposition
Disease cycle:
CROP DISEASE NAME CAUSAL ORGANISM
wheat Stem/ black rust Puccinia graminis tritici
Brown/ leaf rust Puccinia triticana
Yellow rust Puccinia striiformis
Loose smut Ustilago tritici
Leaf blight Alternaria triticina
Karnal bunt Neovossia indica
Ear cockle Auguina tritici
Powdery mildew Erysiphe graminis var. tritici
sugarcane Red rot Colletotrichum falcatum
smut Ustilago scitaminca
Grassy shoots Candidatus phytoplasma
Ratoon stunting Leifsonia xyli subsp. xyli Clavibacter xyli
Pokkah boeng Fusarium moniliforme or Fusarium subglufinans
sunflower Sclerotinia stem rot Sclerotinia sclerotiorum
Alternaria blight Alternaria helianthi
mustard Alternaria blight Alternaria brassicae
White rust Albuga candida
Management:
• No resistant variety is available
• Chemical spray during flowering , fruit set
• Topsin , Karathane , Bordedaux mixture
• Carbendazim, Hexaconazole
• Sanitation
• Destroy crop residue
• Proper nutrient application
• Sulphur spray
• Spray of 5% urea in fallen leaves for early decomposition
Disease cycle:
CROP DISEASE NAME CAUSAL ORGANISM
wheat Stem/ black rust Puccinia graminis tritici
Brown/ leaf rust Puccinia triticana
Yellow rust Puccinia striiformis
Loose smut Ustilago tritici
Leaf blight Alternaria triticina
Karnal bunt Neovossia indica
Ear cockle Auguina tritici
Powdery mildew Erysiphe graminis var. tritici
sugarcane Red rot Colletotrichum falcatum
smut Ustilago scitaminca
Grassy shoots Candidatus phytoplasma
Ratoon stunting Leifsonia xyli subsp. xyli Clavibacter xyli
Pokkah boeng Fusarium moniliforme or Fusarium subglufinans
sunflower Sclerotinia stem rot Sclerotinia sclerotiorum
Alternaria blight Alternaria helianthi
mustard Alternaria blight Alternaria brassicae
White rust Albuga candida
Page | 66
Downy mildew Peronaspora brassicae
Sclerotinia stem rot Sclerotinia sclerotiorum
gram wilt Fusarium oxysporium f.sp. ciceris
Grey mould Botrytis cinerea
Ascochyta blight Ascochyta rabiei
lentil rust Uromyces fabae
wilt Fusarium oxysporum f.sp. lentis
cotton Anthracnose Colletotrichum capsici ;Glomerella gossypii
Vascular wilt Fusarium oxysporum f.sp. vasinfectum
Black arm Xanthomonas compestris pv. Malvacearum
pea Powdery mildew Erysiphe pisi
Downy mildew Peronospora viciae
Pea rust Uromyces fabae
mango anthracnose Colletotrichum gloeosporioides
Mango malformation Fusarium moniliforme var. subglutinans
Bacterial blight Xanthomonas campestris pv mangiferaeindicae
Powdery mildew Oidium mangiferae
citrus canker Xanthomonas campestris pv. Citri
Citrus gummosis Phytophthora nicotianae var. parasitica, p. palmivora,
p.citrophthora
grapevine Downy mildew Plasmopara viticola
Powdery mildew Uncinula necator
anthracnose Telomorph - Elsinoe ampelina ;Anamorph - Sphaceloma
ampelinum
apple scab Ventura inaequalis
Powdery mildew Podosphaera lecotricha
Fire blight of apple Erwinia amylovora
Crown gall Agrobacterium tumefaciens
peach Leaf curl Taphrina deformans
Strawberry Leaf spot Mycospharella fragarieae
potato Early blight Alternaria solani
Late blight Phytopthora infestans
Black scurf Rhizoctonia solani
Leaf roll Potato leaf roll virus
mosaic • Mild mosaic - Potato virus X (PVX)
• Super mild mosaic - Potato virus – A
• Severe mosaic - Potato virus Y ( PVY)
• Rugose mosaic of potato - Potato virus X and
potato virus Y
cucurbits Downy mildew Pseudoperonospora cubensis
Powdery mildew Sphaerotheca fuliginea Erysiphe cichoracearum
wilt Erwinia tracheiphila
Downy mildew Peronaspora brassicae
Sclerotinia stem rot Sclerotinia sclerotiorum
gram wilt Fusarium oxysporium f.sp. ciceris
Grey mould Botrytis cinerea
Ascochyta blight Ascochyta rabiei
lentil rust Uromyces fabae
wilt Fusarium oxysporum f.sp. lentis
cotton Anthracnose Colletotrichum capsici ;Glomerella gossypii
Vascular wilt Fusarium oxysporum f.sp. vasinfectum
Black arm Xanthomonas compestris pv. Malvacearum
pea Powdery mildew Erysiphe pisi
Downy mildew Peronospora viciae
Pea rust Uromyces fabae
mango anthracnose Colletotrichum gloeosporioides
Mango malformation Fusarium moniliforme var. subglutinans
Bacterial blight Xanthomonas campestris pv mangiferaeindicae
Powdery mildew Oidium mangiferae
citrus canker Xanthomonas campestris pv. Citri
Citrus gummosis Phytophthora nicotianae var. parasitica, p. palmivora,
p.citrophthora
grapevine Downy mildew Plasmopara viticola
Powdery mildew Uncinula necator
anthracnose Telomorph - Elsinoe ampelina ;Anamorph - Sphaceloma
ampelinum
apple scab Ventura inaequalis
Powdery mildew Podosphaera lecotricha
Fire blight of apple Erwinia amylovora
Crown gall Agrobacterium tumefaciens
peach Leaf curl Taphrina deformans
Strawberry Leaf spot Mycospharella fragarieae
potato Early blight Alternaria solani
Late blight Phytopthora infestans
Black scurf Rhizoctonia solani
Leaf roll Potato leaf roll virus
mosaic • Mild mosaic - Potato virus X (PVX)
• Super mild mosaic - Potato virus – A
• Severe mosaic - Potato virus Y ( PVY)
• Rugose mosaic of potato - Potato virus X and
potato virus Y
cucurbits Downy mildew Pseudoperonospora cubensis
Powdery mildew Sphaerotheca fuliginea Erysiphe cichoracearum
wilt Erwinia tracheiphila
Page | 67
rose dieback Botrytis cinerea
Powdery mildew Podosphaera pannosa
Black leaf spot Diplocarpon rosae
marigold Botrytis blight Botrytis cinerea
Onion &
garlic
Purple blotch of onion Alternaria porri
Stemphylium blight of onion and garlic Stemphylium vesicarium
coriander Stem gall Protomyces macrosporus
chilli Anthracnose and fruit rot Colletotrichum capsica
Leaf curl Chilli leaf curl virus
Chilli wilt Fusarium oxysporum f.sp.capsici
turmeric Leaf spot Colletotrichum capsica
rose dieback Botrytis cinerea
Powdery mildew Podosphaera pannosa
Black leaf spot Diplocarpon rosae
marigold Botrytis blight Botrytis cinerea
Onion &
garlic
Purple blotch of onion Alternaria porri
Stemphylium blight of onion and garlic Stemphylium vesicarium
coriander Stem gall Protomyces macrosporus
chilli Anthracnose and fruit rot Colletotrichum capsica
Leaf curl Chilli leaf curl virus
Chilli wilt Fusarium oxysporum f.sp.capsici
turmeric Leaf spot Colletotrichum capsica
Page | 68
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