Integrated disease management Maize diseases

Integrated disease management Maize diseases

2. INTEGRATED DISEASE MANAGEMENT
OF MAIZE

3. INTRODUCTIONINTRODUCTION
•Maize one of the major cereals
•Grown in irrigated conditions & rainfed
•Food, feed and fodder crop.
•Among cereals, maize in India
•Ranks 5th in total area,
• Fourth in total production
•Third in yield per hectare.

4. Major diseases of maize
•Turcicum leaf blight,
•Sorghum downy mildew,
•Common rust and
•Post-floweriisng stalk rots

5. Sporadic diseases are
•Mayadis leaf blight,
•Phaeosphaeria leaf spot,
•Brown spot,
•Fusasium wilt,
•Polysora rust,
•Cyst and lesion nematodes

6. Diseases and stage of crop
•Most diseases occur in late vegetative phase and
during grain formation.
•Root and stalk rots cause premature plant death or
contribute to lodging and harvest losses through
weakened stalks.
•
Ear and storage rots further reduce the feeding
value of the grain and a few of these organisms
produce chemicals which are toxic to animals.

7. Yield loss by major diseases under experimental Yield loss by major diseases under experimental
conditions in susceptible cultivars of maize conditions in susceptible cultivars of maize
Disease Loss (%)
Bacterial stalk rot 100
Pythium stalk rot 100
Late wilt 50.9
Charcoal rot 39.5
Maydis leaf blight 30.3
Turcicum leaf blight 66.0
Common rust 32.0
Brown spot 27.0
Brown stripe downy mildew 63.0
Banded leaf and sheath blight 40.5

8. Estimation of losses due to major diseases of maize in IndiaEstimation of losses due to major diseases of maize in India
Disease group Loss (%)
Seed and seeding blights 0.2
Downy mildews 2.0
Foliar diseases
(Turcicum leaf blight, Maydis leaf blight,
Phaeosphaeria leaf spot, rust, )
5.0
Stalk rots, root rots, ear rots 5.0
Sheath blights, smut, viruses and other 1.0
Total 13.2

9. Important diseases of maize, their distribution and economic importanceImportant diseases of maize, their distribution and economic importance
Sl.
No.
Disease Pathogen
Plant parts
affected
Extent
of
yield
loss
Distribution
Mode of
survival
1Turcicum leaf
blight
Exserohilum
turcicum
Leaf 66% Jammu and Kashmir,
Himachal Pradesh, Sikkim,
West Bengal, Meghalaya,
Tripura, Assam, Rajasthan,
Uttar Pradesh, Bihar, Madhya
Pradash, Gujarat,
Maharashtra, Andhra Pradesh,
Karnataka, Tamil Nadu.
Soil, Plant
debris
2Maydis leaf
blight
Drechslera
maydis
Leaf, Leaf
sheath, Ear
husk
30% Jammu and Kashmir,
Himachal Pradesh, Meghalaya,
Soil Plant Punjab, Haryana,
Rajasthan, Delhi,
Uttar Pradesh, Bihar, Madhya
Pradash, Gujarat,
Maharashtra, Andhra Pradesh,
Karnataka, Tamil Nadu.
Soil, plant
3Common rust Puccinia
sorghi
Leaf, Leaf
sheath, Ear
husk, Tassel
32% Jammu and Kashmir, Sikkim,
West Bengal, Punjab (winter),
Haryana, Rajasthan, Delhi,
Uttar Pradesh, Bihar, Madhya
Pradash, Gujarat,
Maharashtra, Andhra Pradesh,
Karnataka, Tamil Nadu.
Uredospores
4Phaeosphaeria
leaf spot
Phaeosphaeri
a maydis
Leaf 25% Sikkim, WB, UP, HP,
Maharashtra, Karnataka
Plant debris

10. Important diseases of maize, their distribution and economic importance Important diseases of maize, their distribution and economic importance
(Contd..)(Contd..)
Sl.
No.
Disease Pathogen
Plant parts
affected
Extent
of yield
loss
Distribution
Mode of
survival
5 Chrysanthemi
stalk rot
Erwinia
chrysanthemi pv.
zeae
Stalk, root 100% HP, Sikkim, WB, Punjab,
Haryana, Rajasthan, Delhi, UP,
Bihar, MP, AP.
Soil
6 Pythium stalk
rot
Pythium
aphanidermatum
Stalk, root 100% Sikkim, HP, WB, Punjab,
Haryana, Rajasthan, Delhi, UP,
Bihar.
Soil
7 Fusarium Wilt
and stalk rot
Fusarium
moniliforme
Stalk, Ear 26% Rajasthan, UP, Bihar, AP,
Karnataka
Soil
8 Late wilt Cephalosporium
maydis
Stalk, Ear 51% Rajasthan, UP, Bihar, AP. Soil, seed
9 Charcoal
stalk rot
Macrophomina
phaseolina
Stalk, Ear 40% JK, WB, Punjab, Haryana, Delhi,
UP, MP, AP, Karnataka, TN.
Soil, O
10Brown stripe
downy
mildew
Sclerophtora
raysiae var. zeae
Leaf 63% HP, Sikkim, WB, Meghalaya,
Punjab, Haryana, Rajasthan,
Delhi, UP, Bihar, MP, Gujarat
Soil,
Oospore
11Philippine
downy
mildew
Peronosclerospora
philippinensis
Systemic 100% Punjab, Haryana, Delhi, UP,
Bihar, MP.
Kans grass

11. Important diseases of maize, their distribution and economic importance Important diseases of maize, their distribution and economic importance
(Contd..)(Contd..)
Sl.
No.
Disease Pathogen
Plant parts
affected
Extent
of yield
loss
Distribution
Mode of
survival
12Sorghum
downy
mildew
P. sorghi Whole plant 100% Rajasthan, Gujarat,
Maharashtra, AP, Karnataka,
Tamil Nadu
Soil,
Oospores
13Sugarcane
downy
mildew
P. sacchari While plant 100% UP, Bihar Soil,
Oospores
14Brown spot Physoderma
maydis
Leaf and
sheath
27% JK, HP, Sikkim, West Bengal,
Karnataka Punjab, Rajasthan,
MP
Soil, Resting
spores
15Banded leaf
and sheath
blight
Rhizoctonia
solani f.sp.
sasakii
Leaf and
sheath
41% JK, HP, Sikkim, Punjab,
Karnataka Haryana, Rajasthan,
Delhi, UP, Bihar
Soil, debris
16Cyst
nematode
Heterodera zeae Root Rajasthan, MP, Bihar, UP,
Karnataka
Soil
17Pohysora rust Puccinia polysora Leaf & sheath 50% Karnataka, AP, Maharshstra Soil, plant

12. DM of Maize
•Number of downy mildew fungi.
•Crazy top
•Peronosclerospora philippinensis
•P. maydis, P. sorghi, P. sacchari
•Sclerophthora rayssiae zeae.

13. Symptoms :
•Most of the time symptoms are similar.
•P. sacchari Long, broad continuous yellowish chlorotic stripes
along veins.
•Leaf shredding not seen but in severely infection – later stage
shredding seen.
•Even on base of tassel downy growth seen.
•Miniature leaves on tassel. Ganga – 3 Multiple ears.
•Branching of stem.
•Mainly on top young leaves.
•Compared to old matured lower leaves.
•Secondary spread is seen yellow stripes.

14. Peronosclerospora sacchari – sugarcane DM

15. Disease cycle :
•Oospores - Alternate hosts.
•P. sacchari - Maize & S. cane.
•P. philippinensis- Many alternatehosts
,Sorghum, kansas grass
•Sclerophthora macrospora : Seed.
•P. maydis : Internally seed
•P. sacchari : Internallyseed
•S. rayssiae zeae : Internally seed

•Spore production during night (:. congenial conditions)
•Early stage of crop ® ­ Sporangia.
•Later stage ® ¯ sporangia.
•Zn deficiency ® ­ disease.
•Usually June – July sown crop ­ disease.

16. •CRAZY TOP OF CORN:
• Symptoms
The most characteristic symptom is the development of
chlorotic streaks on the leaves. Plants exhibit a stunted and
bushy appearance due to shortening of the internodes. White
downy growth is seen on the lower surface of leaf. Downy
growth also occurs on bracts of green unopened male flowers in
the tassel. Small to large leaves are noticed in the tassel.
Proliferation of auxillary buds on the stalk of tassel and the cobs
is common (Crazy top).
DISEASE CYCLE:
1
0
infection: sporangiophores and sporangia
2
0 infection : oospores

17. CRAZY TOP OF CORN:

18. •Favourable Conditions
•Low temperature (21-33˚C)
•High relative humidity (90 per cent) and drizzling.
•Young plants are highly susceptible.
•Management
•Deep ploughing.
•Crop rotation with pulses.
•Rogue out infected plants.
•Treat the seeds with metalaxyl at 6g/kg.
•Spray the crop with Metalaxyl + Mancozeb @ 1kg on 20th
day after sowing.
•Grow resistant varieties and hybrids viz. CO1, COH1and
COH2.

19. Brown stripe downy mildew
(Sclerophthora rayssiae var. zeae)
•SYMPTOMS
•Lesions on the leaves develop as
narrow chlorotic stripes,
•variable in length, 3-7 mm wide.
•These stripes extend in parallel
fashion and have well-defined margins
because of their being vein limited.
•Stripes in advanced stages become
necrotic and present a brown burnt
appearance to the leaves.
•A fine downy growth can be seen on
the stripes.

20. Management
1) Resistant maize cultivars,
Hybrids Ganga 5, Ganga 9,
Composites, Kisan, Tarun, Naveen, Sweta, Kanchan.
2)Plant maize at least a fortnight before the onset of rains. Incidence of the
disease becomes less if planting is done during dry season.
3) Select well drained fields for maize planting,
or arrange proper drainage to drain out the excess rain water.
4) The disease can be minimized by spraying the foliage with fungicides
such as metalaxyl or mancozeb (0.3%).
First spraying should be done about a month after planting or as soon as
the disease symptoms are seen.
Other 3-4 sprays should be done at 10-15 days intervals depending on
severity of the disease.
5) Burn the crop residue after the harvest.
6) Practice three year crop rotation to minimize the initial inoculum load in
the field.

21. Sorghum downy mildew (Peronosclerospora sorghi)
Symptoms:
•First appear as rolling and twisting of upper leaves
•Malformation of tassel.
•Stunting, chlorosis,
•White stripes with downy fungal growth on both leaf surfaces.
• Affected leaves may often tear linearly causing leaf shredding.

22. Disease management
1)Plant disease resistant maize cultivars- Suwan.
Amongst the released hybrids, Ganga Safed 2 least
susceptible.
2) Treating maize seed with a systemic fungicide, metalaxyl @
3 g/kg
3) Provide adequate soil drainage or avoid planting in low, wet
spots.
4) Planting should be done at least a fortnight before the onset
of rains.
5) The disease can be minimized by foliar spraying of fungicides
like mancozeb / metalaxyl @ 3 kg/ha at frequent intervals.
6) Burn the residues after the crop harvest.

23. Turcicum leaf blight
(Exserohilum turcicum)

24. 1. long elliptical grayish green or tan lesions on
leaves 2.5 to 25 cm in length and 4 cm in
width.
2. Lesions first appear as slightly oval, water
soaked, small spots on lower leaves and increase
in size and number
3. Progress upwards until a complete burning of
the foliage.
Under high humidity the whole leaf area becomes
necrotic and plants appear as dead.
4.Spores produced on the under surface are arranged
in concentric zones resembling a target like
pattern.
5. Lesions may be extended to husk.
Turcicum leaf blight (Exserohilum turcicum)
symptoms

25. Disease management
1)Use of resistant cultivars
DMH-2, Prabha
2) Two or three foliar sprays with 0.25 % mancozeb or
zineb at 10-15 days intervals.
First spray soon after the disease appearance.
3) Application of urea followed by a light irrigation helps
to minimize the disease as this disease becomes
serious under poor management, i.e., under low
nitrogen and water stress.

26. Seed rots and seedling blights
•Pathogens involved are
•Pythium aphanidermatum,
•Cephalosporium acremonium,
•Fusarium moniliforme,
•Rhizoctonia sp.,
•Aspergillus niger
• Penicillium oxalicum.

27. •The infected seeds broken having
blemishes, spots, silk-cut and show
signs of softening, rotting,
•The seedlings are thin, patchy growth,
post-emergence damping-off and
brown sunken lesion on mesocotyl.
• Water – soaked areas are also seen on
the collar region.
•Seedlings may wilt, collapse or topple
from the point of emergence.
•Leaves become flaccid or begin to dry
partially or wholly and sometimes
external fungus growth can also be seen.

28. Disease management:
•1)Certified seeds.
• 2)Farmers seeds can be treated with thiram or bavistin @ 2.0
g/kg.
• 3)Good quality seed taken from disease-free healthy plants.
• 4)Eliminate seed lots showing streaking, pericarp injury or
those showing any kind of blemishes;
•5) Avoid planting of light weight or chaffy kernels,
•6)Avoid ridge-planting especially to prevent Rhizoctonia
infection.
• 7) Planting should be done preferably at a time when soil
temperature is more than 10°C.

29. Maydis leaf blight
(Drechslera maydis)

30. 1. Disease appears as small and diamond shaped
lesions on leaf and as they mature, they
elongate.
2. Increase in width of lesions is restricted by the
adjacent veins
3. Finally lesions typically assume rectangular
appearance.
4. Lesions are reddish brown in colour with dark
brown borders.
5. Symptoms may be confined largely to leaves
(race O) or may develop on leaves, sheaths,
stalks, husks, and cobs.
Symptoms

31. Disease cycle
Disease is favoured by high relative humidity and warm
temperature (25-32°C).
Pathogen survives in plant debris and collateral hosts like
sorghum, wheat, barley, oats, teosinte and other grasses.
Disease management
1). Clean cultivation may reduce early infection.
2) Use protective fungicides Dithane-Z-78, Dithane M-45) @ 2.5
g/l as soon as first symptoms of the disease appear.
3) Grow resistant maize cultivars, such as Deccan, Deccan-103,
Ganga-5, Deccan-101, VL-42, Ganga-4.


32. Fusarium stalk rot
symptoms
Two species, F. moniliforme and F.
graminearum are associated with the
disease.
The incidence of the former is more severe
in low land tropical areas while the
latter is present in cooler high lands.
The symptoms become conspicuous when
the crop enter senescence phase i.e.
kernels are in ‘blister’ stage to the
phase when dry matter is near
maximum.

33. Fusarium stalk rot
Pathogen
commonly affects the roots, crown region and lower
internodes,
 when split open, the stalks show a pink-purple
discolouration In plants affected by F. graminearum,
blue purple mycelial mat of Gibberella zeae develop
on the rind.
Diseasemanagement
•Crop rotation and avoid water logging
•Seed treatment with carbendazim or thiram @ 3 g/kg
•Soil application of organic amendment will reduce
inoculum

34. Charcoal stalk rot ( Macrophomina
phaseolina)

35. Charcoal stalk rot
(Macrophomina phaseolina)
This disease is prevalent comparatively in drier maize
growing areas.
The symptoms of the disease becomes apparent as the
plants approach maturity.
Affected plants dry prematurely, the affected
internodes become straw coloured, pith becomes
disintegrated.
Presence of small pin-head like black sclerotia on
the rind of the stalks is a distinguishing character.

36. Charcoal stalk rot (Macrophomina phaseolina)
FAVOURABLE CONDITIONS Water stress at or after
flowering has been found to predispose the plants to
infection. The fungus survives in soil and plant
debris.

The pathogen has wide host range. Development of
charcoal rot is favoured by dry weather with high
temperature (37°C) at the time of silking
Imbalanced fertilizer application and high plant
density influence disease prevalence and severity.

37. Disease management
1)Plant resistant maize cultivars, such as Ganga 9, Deccan 101, Him 128,
Kanchan, Diara Composite, Hunius Composite and Sangam.
2) Field sanitation and crop rotation
3)Seed treatment with carbendazim or thiram or carboxin @ 3 g/kg
or Trichoderma harzianum @ 6 g/kg.
4)Charcoal rot can be minimized by maintaining moist soils, especially
during dry periods after tasselling by providing copious irrigation.
5) Apply balanced fertilizer doses and avoid high doses of N, apply
optimum level of potash,
6) Plant population should be kept at a lower level, i.e., upto 50-60
thousand plants per hectare.
7) Crop rotation with paddy or sesamum.
8) Soil application of organic amendment and green manuring.

38. Common rust (Puccinia sorghi)

39. Common rust (Puccinia sorghi)
symptoms
•It is most conspicuous when plants approach
tasseling.
• It is recognized by small, oval to elongate pustules.
• Pustules are brown in early stages of infection;
•later, the epidermis is ruptured and the lesions turn
black as the plant matures.
• Alternate host (Oxalis spp.) are frequently infected
with light orange coloured pustules.
• Oxalis corniculata has been found to be
susceptible under artificial inoculations with
teliospores in India.

40. Disease management
1)Select resistant maize cultivars for planting in
areas where rust becomes problem,
e.g., DHM-1, DHM-103, Ganga 5.
2)The severity of the disease during rabi season
can be reduced by spraying mancozeb or zineb
@ 2.5 g/l, or hexaconazole / propiconazole @
1 ml/l.
The first spray should be given as soon as rust
pustules appear on the foliage and then two or
three more sprays at 10-15 days intervals.

41. Banded leaf and sheath blight
(Rhizoctonia solani f.sp. sasakii)

42. Banded leaf and sheath blight (Rhizoctonia
solani f.sp. sasakii)
Symptoms of this disease which
develop on leaves and sheaths are
characteristic concentric spots that
cover large areas of infected leaves
and husks.
 The main damage in the humid
tropics is a brownish rotting of
ears,
 which show conspicuous light
brown cottony mold with small,
round, black sclerotia.
 The developing ear is completely
damaged and dries up prematurely
with cracking of the husk leaves.

43. Disease management
1)Clean cultivation and destruction of crop
debris
2) Stripping of lower 2-3 leaves along with
their sheaths reduces the initial
inoculum.
3) Spray carbendazim1 g / l
or propiconazole 1 ml / l.

44. Bacterial stalk rot (Erwinia carotovora f. sp. zeae)

45. Bacterial stalk rot (Erwinia
carotovora f. sp. zeae)
•Symptoms appear as softening of basal internodes:
• Plants may wilt and emit fermenting odour:
• Ears may became blighted and rot.
•The high incidence of this disease is favoured
• by high temperature (28°C and above) and high
ambient moisture
• which commonly prevail in most of the maize
growing areas 3 to 4 week after planting.

46. Disease management
1)Grow resistant hybrids and composites such as
hybrid Ganga Safed,
2) Avoidance of water logging, provide proper drainage.
3) Planting should be done in the second fortnight of
June. It helps in reducing stalk rot incidence in
northern states of the country. Planting of the crop on
ridges rather than in flat soil is advocated.
4) Provide balanced fertilizers, especially potash, which
helps in making the plants more resistant.

47. •5) Apply chlorine water irrigation (100-1000 ppm)
when the crop is at pre-flowering stage of the crop
(4-7 week crop stage).
•This pathogen is highly sensitive to chlorine.
Efficient control of this disease by using bleaching
powder (CaOCl2H2O2 containing 33% chlorine) @
3.3 g per 10 liters of water could be obtained by
drenching of basal stalk region when plants are at
knee-high stage
•Resistance to this disease has been identified in CM
104 and CM 600.

48. Maize mosaic stripe virus: M Stp V.
Vector leafhopper Peregrinus maidis
Virus diseases
Maize Dwarf Mosaic Virus

49. Virus diseases
Three viruses occur on maize in India.
These are : maize mosaic virus I, maize
mosaic and vein enation. Maize mosaic
has been found to be prevalent in several
states and the incidence ranges from 2.2
to 10.6%. Resistance of a high order has
been identified in inbred lines CM 103 and
CM 1 04. The released cultivars have not
been reported to suffer much from viruses.

50. Maize Chlorotic Dwarf Virus
Symptoms:
•Leaves may be reddish and yellow, but this will depend on
environment, hybrid, or time of infection
•Veinbanding occurs when young leaves become chlorotic within
the whorl
•Plants may be stunted and internodes may be shortened or stunted
•Leaves may also be torn, twisted or have swollen veins with a dull,
rough surface
•Plants may also be infected with maize dwarf mosaic virus

51. Disease Management:
Use tolerant or resistant commercial corn
hybrids.
Control of Johnson grass with herbicides may be
beneficia

52. •Maize Dwarf Mosaic Virus
Symptoms:
•Symptoms often begin as chlorotic spots and
streaks on green, young leaves, which later
develop into a mottle or a mosaic pattern
•Viral strain, corn genotype, and stage of corn
development at the time of infection will affect
the type of symptoms
•Upper internodes of corn may be shortened, and
excessive tillering may occur
•Ear formation and development may slow, which
may cause grain yield loss
•Hybrids infected early in their growth stage may
be stunted

53. Time of Occurrence:
Symptoms appear six weeks after aphids feed and transmit
this virus
Disease Management:
Use tolerant commercial corn hybrids
Avoidance of aphid vectors
Control of Johnson grass with herbicides may be beneficial

54. CORN INTEGRATED DISEASE
MANAGEMENT
•Managing corn diseases requires an integrated approach to limit disease
and yield losses. The use of disease-resistant hybrids, crop rotations,
various tillage practices, balanced fertility, fungicides, control of other
pests and weeds, and various other cultural practices is needed to provide
the broadest spectrum of control of corn pathogens. Table 14.3 lists
diseases known to cause yield losses in Illinois and the relative
effectiveness of various control measures.
•Planting disease-resistant hybrids. The use of resistant hybrids is the
most economical and efficient method of disease control. Although no
single hybrid is resistant to all diseases, hybrids with combined resistance
to several major diseases are available. Corn producers should select high-
yielding hybrids with resistance or tolerance to major diseases in their
area.

55. •Rotating crops. Many common pathogens require the presence of a
living host crop for growth and reproduction. Examples of such corn pathogens
include many of the foliar diseases (Helminthosporium leaf diseases,
Physoderma brown spot, Goss’s wilt, gray leaf spot, eyespot) and nematodes.
Rotating to nonhost crops (i.e., soybean) “starves out” these pathogens,
resulting in a reduction of inoculum levels and the severity of disease.
Continuous corn, especially in combination with conservation tillage practices
that promote large amounts of surface residue, may result in severe outbreaks
of disease.
•Tilling. Tillage programs that encourage rapid residue decomposition before
the next corn crop is planted help reduce population of pathogens that
overwinter in or on crop debris. Although a clean plowdown is an important
disease-control practice, the possibility of soil loss from erosion must be
considered. Other measures can provide effective disease control if
conservation tillage is implemented. Examples of diseases partially controlled
by tillage include stalk and root rots, Helminthosporium leaf diseases,
Physoderma brown spot, Goss’s wilt, gray leaf spot, anthracnose, ear and
kernel rots, eyespot, and nematodes.

56. •Managing fertility. Balanced fertility and fertility levels play an
important role in development of diseases such as Stewart’s wilt,
seedling blights, leaf blights, smut, stalk rots, ear rots, and nematodes.
Diseases may be more severe where there is excess nitrogen and a
lack of potassium, or both. Healthy, vigorous plants are more tolerant of
diseases and better able to produce a near-normal yield.
•Using foliar fungicides. The decision to apply a foliar fungicide should
be based on the levels of disease incidence and severity and on certain
risk factors. Factors that increase the risk of foliar diseases include
these: previous crop was corn, or corn debris on the soil surface is
prevalent; weather was rainy in July and August, with high dew points;
a susceptible hybrid was planted; and the crop was planted later than
normal

57. Disease rating scales for foliar diseases of Maize (1-5 scale) Disease rating scales for foliar diseases of Maize (1-5 scale)
(Turcicum leaf blight, Rust, Maydis Leaf blight) (Turcicum leaf blight, Rust, Maydis Leaf blight)
Grade Degree of infection
1 Very slight infection, one to two restricted spots
(lesions) on lower leaves or traces
2 Slight to moderate infection on lower leaves a few
scattered lesions on lower leaves
3 Abundant lesions on lower leaves, few on middle
leaves
4 Lesions abundant on lower and middle leaves
extending to upper leaves
5 Lesions abundant on all leaves. Plants may be
prematurely killed by blight/ rust etc.

58. Disease rating scales for post flowering stalk rots of Maize Disease rating scales for post flowering stalk rots of Maize
(1-9 scale) (1-9 scale)
Grade Degree of infection
1 Internode discolouration very slight (traces)
2 25% of internode discoloured
3 25-50% of internode discoloured
4 50-75% of internode discoloured
5 75-100% of internode discoloured
6 1/2 discolouration of adjacent internodes
7 Discolouration of three internodes
8 Discolouration of four internodes
9 Discolouration of five internodes. Plant dries
completely and lodge

59. CONCLUSIONCONCLUSION
Diseases of maize are strongly influenced by weather conditions and are
very difficult to predict.
They are best controlled by the use of resistant or tolerant hybrids and a
balanced fertility programme.
Most of the disease causing agents/ pathogens has the capacity to over
winter and tillage and crop rotation are common cultural practices which will
help to reduce sources of disease organisms, particularly if disease has
been prevalent from the previous years.
Integrated disease management practices involving, cultural, biological and
chemical approaches will be of immense help to reduces losses caused by
maize diseases.

60. •REFERENCES:
•Maize crop science
by S C Panda
•Crop diseases
By L Darwin christdhas Henry
Thiru h lewin
•orgprints.org/8206/1/Integrated_disease_management-jkohl.pd

•link.springer.com/article/10.1023%2FA%3A1009694632036