Diseases of maize, sorghum and pearl millet.ppt

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1. Diseases of Maize
Major diseases
Downy mildew/Crazy top -Peronosclerospora sorghi
Leaf blight -Helminthosporium maydis (Syn: H. turcicum)
Rust -Puccinia sorghi
Head smut -Sphacelotheca reiliana
Charcoal rot -Macrophomina phaseolina
Minor diseases
Bacterial Stalk rot -Erwinia dissolvens
Mosaic -Maize mosaic potyvirus
Brown spot -Physoderma maydis

2. Symptoms
Chloroticstreaksontheleaves.
Plantsexhibitastuntedandbushyappearanceduetoshorteningofthe
internodes.
Whitedownygrowthisseenonthelowersurfaceofleafandbractsofgreen
unopenedmaleflowersinthetassel.Smalltolargeleavesarenoticedinthe
tassel.
Proliferationofauxillarybudsonthestalkoftasselandthecobs(Crazytop).
Downy mildew/Crazy top -Peronosclerospora sorghi

3. Pathogen
The fungus grows as white downy growth consisting of
sporangiophoresand sporangia.
Sporangiophoresare quite short and stout, branch profusely
into series of pointed sterigmatawhich bear hyaline, oblong or
ovoid sporangia.
Sporangia germinate directly and infect the plants.
In advanced stages, oospores are formed which are spherical,
thick walled and deep brown.
Favourable Conditions
• Low temperature (21-33°C)
• High relative humidity (90 per cent) and drizzling.
• Young plants are highly susceptible.

4. Mode of spread
Theprimarysourceofinfectionisthroughoosporesinsoilandalsodormant
myceliumpresentintheinfectedmaizeseeds.
Secondaryspreadisthroughairborneconidia.
Somespeciesthatcausedownymildewcanalsobeseedborne,although
thisislargelyrestrictedtoseedthatisfreshandhashighmoisturecontent.
Oosporesarereportedtosurviveinnatureforupto10years.
Management
• Deep ploughing.
• Crop rotation with pulses.
•Grow resistant varieties and hybrids TNAU maize hybrid CO-6 and COH (M) 8
• Rogue out infected plants.
• Treat the seeds with metalaxylat 6g/kg.
• Spray the crop with Metalaxyl+ Mancozeb@ 1kg at 20 days after sowing.•

5. Leaf blight -Helminthosporium maydis (Syn: H. turcicum)
Symptoms
Thefungusaffectsthecropatyoungstage.
Smallyellowishroundtoovalspotsareseenonthe
leaves.
Thespotsgraduallyincreaseinareaintobiggerelliptical
spotsandarestrawtograyishbrowninthecentrewith
darkbrownmargins.
Thespotscoalescegivingblightedappearance.The
surfaceiscoveredwitholivegreenvelvettymassesof
conidiaandconidiophores.
Pathogen
Conidiophoresareingroup,geniculate,milddarkbrown,
paleneartheapexandsmooth.
Conidiaaredistinctlycurved,fusiform,paletomilddark
goldenbrownwith5-11septa.

6. Favourable Conditions
•Optimumtemperatureforthegerminationofconidiais8to27°Cprovided
withfreewaterontheleaf.
•Infectiontakesplaceearlyinthewetseason.
Mode of spread
•Itisaseed-bornefungus.Italsoinfectssorghum,wheat,barely,oats,
sugarcaneandsporesofthefungusarealsofoundtoassociatewithseedsof
greengram,blackgram,cowpea,varagu,Sudangrass,Johnsongrass.
Management
•Seed treatment with Bacillus subtilis@ 10g/ kg
•Spray propiconazole25% EC @ 0.1% on 35 and 50 DAS
•Spray kresoxim-methyl 44.3% SC @ 1 ml/ l of water

7. Rust -Puccinia sorghi
Symptoms
Circulartooval,elongatedbrownpowdery
pustulesarescatteredoverbothsurfaceofthe
leaves.
Pustulesbecomebrowntoblackowingtothe
replacementofreduredosporesbyblack
teliospores.
Pathogen
Uredosporesaregloboseorellipticalfinelyechinulate,
yellowishbrownwith4germpores.
Teliosporesarebrownishblack,ordarkbrown,oblongto
ellipsoidal,roundedtoflattenedattheapex.Theyaretwo
celledandslightlyconstrictedattheseptumandthespore
wallisthickenedattheapex.

8. Favourable Conditions
• Cool temperature and high relative humidity.
Disease cycle
Primary source of inoculums is uredospores surviving on alternate hosts viz.,
Oxalis corniculata and Euchlaena mexicana.
Management
• Remove the alternate hosts.
• Spray kresoxim-methyl 44.3% SC @ 1 ml/l of water

9. Head smut -Sphacelotheca reliana
Symptoms
Symptomsareusuallynoticedonthecobandtassel.
Largesmutsorireplacethetasselandtheear.
Tasselispartiallyorwhollyconvertedintosmut
sorus.
Thesmuttedplantsarestuntedproducelowyield
andremaingreenerthanthatoftherestofthe
plants.
Pathogen
Smut spores are produced in large numbers which are reddish brown to
black, thick walled, finely spined, spherical.
Favourable Conditions
• Low temperature favours more infection

10. Mode of spread
Thesmutsporesretainitsviabilityfortwoyears.Thefungusis
externallyseedborneandsoil-borne.
Themajorsourceofinfectionisthroughsoil-borne
chlamydospores.
Management
• Field sanitation.
• Crop rotation with pulses.
• Treat the seeds with Captanor Thiramat 4 g/kg.

11. Charcoal rot/post flowering stalk rot -
Macrophomina phaseolina
Symptoms
Theaffectedplantsexhibitwiltingsymptoms.Thestalk
oftheinfectedplantscanberecognizedbygrayish
streak.
Thepithbecomesshreddedandgrayishblackminute
sclerotiadeveloponthevascularbundles.
Shreddingoftheinteriorofthestalkoftencausesstalks
tobreakintheregionofthecrown.
Thecrownregionoftheinfectedplantbecomesdarkin
colour.
Shreddingofrootbarkanddisintegrationofrootsystem
arethecommonfeatures.
Pathogen
The fungus produces large number of sclerotiawhich are
round and black in colour.
It produces pycnidiaon the stems or stalks.

12. FavourableConditions
•Hightemperatureandlowsoilmoisture(drought)
Modeofspread
Thefungushasawidehostrange,attackingsorghum,pearlmillet,
fingermilletandpulses.
Itsurvivesformorethan16yearsintheinfectedplantdebris.
Theprimarysourceofinfectionisthroughsoil-bornesclerotia.
Thefungusoverwintersasasclerotiainthesoilandinfectsthehostat
susceptiblecropstagethroughrootsandproceedstowardsstem.
Management
•Longcroprotationwithcropsthatarenotnaturalhostofthe
fungus.
•Irrigatethecropsatthetimeofearheademergenceto
maturity.
•Avoidnutrientstressandapplypotash@80kg/hain
endemicareas
•[email protected]/hawith50kgofwell
decomposedFYM/sandinsoilat30daysaftersowing

13. Bacterial Stalk rot -Erwinia dissolvens
Symptoms
Thebasalinternodesdevelopsoftrotandgiveawater
soakedappearance.
Amildsweetfermentingodouraccompaniessuch
rotting.Leavessometimeshowsignsofwiltingand
affectedplantstoppledowninfewdays.
Earsmayalsoshowrot.Theyfailtodevelopfurtherand
theearshangdownsimplyfromtheplant
Mode of spread
Borerinsectsplayasignificantroleininitiationofthe
disease.
Theorganismissoilborneandmakesitsentrythrough
woundsandinjuriesonthehostsurface.
Theorganismsurvivessaprophyticallyondebrisof
infectedmaterialsandservesprimaryinoculuminthe
nextseason.

14. Mosaic -Maize mosaic potyvirus
Symptoms
Symptomsappearaschloroticspots,which
graduallyturnintostripescoveringentireleaf
blade.
Chloroticstripesandspotscanalsodevelopon
leafsheaths,stalksandhusks.
Moderatetosevererosettingofnewgrowthis
observed.
Pathogen
It is caused by Maize mosaic potyvirus. Virions are flexuous,
750-900nm long, ssRNA genome.
Disease cycle
It is transmitted in nature by leaf hopper vector, Perigrimus maidis.

15. Brown spot -Physoderma maydis
Water soaked lesions, which are oval, later turn into light green and finally
brown.

16. Diseases of Sorghum
Downy Mildew -Peronosclerospora sorghi
Leaf blight -Exerohilum turcicum (Syn: Helminthosporium turcicum)
Rectangular Leaf spot -Cercospora sorghi
Anthracnose and red rot -Colletotrichum graminicolum
Rust -Puccinia purpurea
Grain smut/Kernel smut / Covered smut / Short smut -Sphacelotheca sorghi
Loose smut/ kernel smut -Sphacelotheca cruenta
Long smut -Tolyposporium ehrenbergii
Head smut -Sphacelotheca reiliana
Ergot or Sugary disease -Sphacelia sorghi
Head mould/Grain mould/Head blight
Phanerogamic parasite -Striga asiatica and Striga densiflora

17. Downy Mildew -Peronosclerospora sorghi
Symptoms
Itinvadesthegrowingpointsofyoungplants,either
throughoosporeorconidialinfection.
Astheleavesunfoldtheyexhibitgreenoryellow
colouration.
Abundantdownywhitegrowthisproducedonthe
lowersurfaceoftheleaves,whichconsistsof
sporangiophoresandsporangia.
Completebleachingoftheleaftissueinstreaksor
stripes.Asmaturetheybecomenecroticandthe
interveinaltissuesdisintegrate,releasingtheresting
spores(oospores)andleavingthevascularbundles
looselyconnectedtogivethetypicalshreddedleaf
symptom.

18. Pathogen
P. sorghiis an obligate parasite systemic in young plant.
The mycelium is intercellular, non-septate.
Sporangiophoresemerge through the stomata in single
or in clusters which are stout and dichotomously
branched.
Spores are single celled, hyaline, globoseand thin
walled.
Oospores are spherical, thick walled and deep brown
in colour.
Favourable Conditions
• Maximum sporulation takes place at 100 per cent relative humidity.
• Optimum temperature for sporulation is 21-23°C during night.
• Light drizzling accompanied by cool weather is highly favourable.

19. Mode of spread
Theprimaryinfectionisbymeansofoosporespresentinthesoilwhich
germinateandinitiatethesystemicinfection.
Oosporespersistinthesoilforseveralyears.
Secondaryspreadisbyair-bornesporangia.
Presenceofmyceliumofthefungusintheseedsofsystemicallyinfected
plantsisalsoasourceofinfection.
Thediseasehasbeenknowntooccurthroughacollateralhost,Heteropogen
centortusonwhichthefungusperpetuatesofthehost.
Sporangiaareformedatnightinlargenumbers.
Management
•Croprotationwithothercropsviz.,pulsesandoilseeds.
•Avoidthesecondaryspreadofthediseasebyroguingouttheinfected
plantssincethewindplaysamajorroleinthesecondaryspreadofthe
disease.
•SeedtreatmentwithMetalaxylat6g/kgofseed.
•SprayMetalaxyl500gorMancozeb2kgorZiram1kgorZineb1kg/ha.

20. Leaf blight -Exerohilum turcicum (Syn: Helminthosporium turcicum)
Symptoms
Thepathogenalsocausesseedrotandseedling
blightofsorghum.
Thediseaseappearsassmallnarrowelongated
spotsintheinitialstageandinduecoursethey
extendalongthelengthoftheleaf.
Onolderplants,thetypicalsymptomsarelong
ellipticalnecroticlesions,strawcolouredinthe
centrewithdarkmargins.
Thestrawcolouredcentrebecomesdarkerduring
sporulation.
Manylesionsmaydevelopandcoalesceonthe
leaves,destroyinglargeareasofleaftissue,giving
thecropaburntappearance.

21. Pathogen
The mycelium is localised in the infected lesion. Conidiophores emerge
through stomata and are simple, olivaceous, septateand geniculate.
Conidia are olivaceousbrown, 3-8 septateand thick walled.
Favourable Conditions
• Cool moist weather.
• High humidity (90 per cent)
• High rainfall.
Mode of spread
The pathogen is found to persist in the infected plant debris.
Seed borne conidia are responsible for seedling infection.
Secondary spread is through wind-borne conidia.
Management
•Use disease free seeds.
•Seed treatment with Bacillus subtilis@ 10g/ kg
•Spray propiconazole25% EC @ 0.1% on 35 and 50 DAS
•Spray kresoxim-methyl 44.3% SC @ 1 ml/ l of water

22. Charcoal rot: Macrophomina phaseolina
Symptoms
Thepathogeniseasilyidentifiablewhenstemsaresplit
longitudinally.
Thecharacteristicappearanceofblackmicrosclerota
(restingbodies)inthevasculartissueandinsidethe
rindofthestalkresultsina‘peppered’lookin
conjunctionwithshreddedinternalvasculartissue
whichisgrey/charcoalincolour.

23. Rectangular Leaf spot -Cercospora sorghi
Symptoms
Thesymptomsappearassmallleafspotswhichenlarge
tobecomerectangularlesionsontheleafandleaf
sheath.
Usuallythelowerleavesarefirstattacked.
The lesions are typical dark red to purplish with lighter
centers.
Thelesionsaremostlyisolatedandlimitedbyveins.The
colourofthespotsvariesfromred,purple,brownor
darkdependinguponthevariety.
Pathogen
Myceliumofthefungusishyalineandseptate.
Conidiophoresemergeinclustersthroughstomata,whichare
brownandsimple,rarelybranched.
Conidiaarehyaline,thinwalled,2-13celledandlongobclavate.

24. Favourable Conditions
• Cool moist weather.
• High humidity (90 per cent)
• High rainfall.
Mode of spread
The conidia survive up to 5 months. The disease spreads through
air-borne and seed borne conidia.
Management
• Use disease free seeds.
• Seed treatment with Bacillus subtilis@ 10g/ kg
•Spray propiconazole25% EC @ 0.1% on 35 and 50 DAS
•Spray kresoxim-methyl 44.3% SC @ 1 ml/ l of water

25. Anthracnose and red rot -Colletotrichum graminicolum
Symptoms
Thefunguscausesbothleafspot(anthracnose)andstalkrot
(redrot).
Thediseaseappearsassmallredcolouredspotsonboth
surfacesoftheleaf.Thecentreofthespotiswhiteincolour
encircledbyred,purpleorbrownmargin.
Numeroussmallblackdotslikeacervuliareseenonthewhite
surfaceofthelesions.
Redrotcanbecharacterizedexternallybythedevelopment
ofcircularcankers,particularlyintheinflorescence.
Infectedstemwhensplitopenshowsdiscoloration,which
maybecontinuousoveralargeareaormoregenerally
discontinuousgivingthestemamarbeledappearance.

26. Pathogen
Themyceliumofthefungusislocalisedinthespot.
Acervuliwithsetaearisethroughepidermis.
Conidiaarehyaline,singlecelled,vacuolateand
falcateinshape.
Favourable Conditions
• Continuous rain.
• Temperature of 28-30°C.
• High humidity.
Mode of spread
The disease spread by means of seed-borne and air-borne
conidia and also through the infected plant debris.
Management
• Use disease free seeds.
• Seed treatment with Bacillus subtilis@ 10g/ kg
•Spray propiconazole25% EC @ 0.1% on 35 and 50 DAS
•Spray kresoxim-methyl 44.3% SC @ 1 ml/ l of water

27. Rust -Puccinia purpurea
Symptoms
Thefungusaffectsthecropatallstagesofgrowth.
Smallflecksonthelowerleaves(purple,tanorred
dependinguponthecultivar).
Pustules(uredosori)appearonbothsurfacesofleaf
aspurplishspotswhichrupturetoreleasereddish
powderymassesofuredospores.
Telioporesdeveloplatersometimesintheold
uredosoriorintelisori,whicharedarkerandlonger
thantheuredosori.
Thepustulesmayalsooccurontheleafsheathsand
onthestalksofinflorescence.

28. Pathogen
Theuredosporesarepedicellate,ellipticaloroval,thinwalled,
echinulatedanddarkbrownincolour.
Theteliosporesarereddishorbrownincolourandtwocelled,
roundedattheapexwithonegermporeineachcell.
Theteliosporesgerminateandproducepromyceliumand
basidiospores.
BasidiosporesinfectOxaliscorniculata(alternatehost)where
pycnialandaecialstagesarise.
Favourable Conditions
• Low temperature of 10 to 12°C favours teliospore
germination.
• A spell of rainy weather favours the onset of the disease.

29. Mode of spread
The uredosporessurvive for a short time in soil and infected
debris.
Presence of alternate host helps in perpetuation of the
fungus.
Management
• Remove the alternate host Oxalis comiculata.
• Spray kresoxim-methyl 44.3% SC @ 1 ml/l of water

31. Grain smut/Kernel smut / Covered smut / Short smut -Sphacelotheca sorghi
Symptoms
Theindividualgrainsarereplacedby
smutsori.
Thesoriareovalorcyclindricalandare
coveredwithatoughcreamyskin
(peridium)whichoftenpersists
unbrokenuptothrashing.
Ratooncropsexhibithigherincidence
ofdisease.

32. Loose smut/ kernel smut -Sphacelotheca cruenta
Symptoms
Theaffectedplantscanbedetectedbeforetheears
comeout.
Theyareshorterthanthehealthyplantswith
thinnerstalksandmarkedtillering.
Theearscomeoutmuchearlierthanthehealthy.
Theglumesarehypertrophiedandtheearhead
givesalooseappearancethanhealthy.
Thesorusiscoveredbyathinmembranewhich
rupturesveryearly,exposingthesporesevenasthe
heademergesfromthesheath.

33. Long smut -Tolyposporium ehrenbergii
Symptoms
Thisdiseaseisnormallyrestrictedtoa
relativelyasmallproportionoftheflorets
whicharescatteredonahead.
Thesoriarelong,moreorlesscylindrical,
elongated,slightlycurvedwitharelatively
thickcreamy-browncoveringmembrane
(peridium).
Theperidiumsplitsattheapextorelease
blackmassofspores(sporeingroupsofballs)
amongwhicharefoundseveraldarkbrown
filamentswhichrepresentthevascular
bundlesoftheinfectedovary.

34. Head smut -Sphacelotheca reiliana
Symptoms
Theentireheadisreplacedbylargesori.
Thesorusiscoveredbyawhitishgrey
membraneoffungaltissue,whichruptures,
beforetheheademergesfromthebootleaf
toexposeamassofbrownsmutspores.
Sporesareembeddedinlong,thin,dark
coloredfilamentswhicharethevascular
bundlesoftheinfectedhead.

35. •Managementofsmuts:
•1.Coveredandloosekernelsmutsareeasilyandeffectivelycontrolledby
treatingtheseedwithaprotectantfungicide.Seedtreatmentprevents
introducingtheheadsmutfungusintouninfestedfields.Fungicideseed
treatmentalsoimprovesandstabilizes
•thestandwhensoilinsectsarenotaproblem.Inaddition,itprovides
protectionagainstseedlingblightfungiinthesoil.
•2.Thereareanumberofphysiologicracesofthethreesorghumsmutfungi,
whichcanalsohybridizewithoneanother;itisextremelydifficulttodevelop
highlyresistantorimmunehybrids,varietiesorcultivarsofsorghum.Those
varieties,hybrids,andtypesofsorghumthatareresistanttoracesof
coveredkernelsmutusuallyareresistanttoracesofloosekernelsmut.
Mostsweetsorghumvarietiesarehighlyresistant.
•3.Promptlyremoveandburnheadsmutgallsbeforethesporesare
scattered.
•4.Sincetheheadsmutfungusmayliveinthesoilforseveralyearsgrow
sorghuminthesamefieldonlyoncein4years.Suchacroprotationalso
helpstocontrolotherdiseasesthatattacktheleaves,heads,stalks,and
roots.

36. Ergot or Sugary disease -Sphacelia sorghi
Symptoms
Thediseaseisconfinedtoindividualspikelets.
Thefirstsymptomisthesecretionofhoneydewfrom
infectedflorets.
Underfavourableconditions,long,straightorcurved,
creamtolightbrown,hardsclerotiadevelop.
OftenthehoneydewiscolonisedbyCrerebella
sorghivulgariswhichgivestheheadablackened
appearance.
Pathogen
The fungus produces septate mycelium. The honey dew is a
concentrated suspension of conidia, which are single celled, hyaline,
elliptic or oblong.
Favourable Conditions
• A period of high rainfall and high humidity during flowering season.
• Cool night temperature and cloudy weather aggravate the disease.

37. Modeofspread
•Theprimarysourceofinfectionisthroughthegerminationofsclerotia
whichreleaseascosporesthatinfecttheovary.
•Thesecondaryspreadtakesplacethroughairandinsect-borneconidia.
•Rainsplashesalsohelpinspreadingthedisease.
Management
•Adjustthedateofsowingsothatthecropdoesnotflowerduring
September-Octoberwhenhighrainfallandhighhumidityfavorthedisease.
•SprayPropiconazole500ml/haatemergenceofearhead(5-10%flowering
stage)followedbyasprayat50%floweringandrepeatthesprayaftera
weekifnecessary

38. Head mould/Grain mould/Head blight
Symptoms
Ifrainsoccurduringthefloweringandgrainfilling
stages,severegrainmouldingoccurs.
ThemostfrequentlyoccurringgeneraareFusarium,
Curvularia,Alternaria,AspergillusandPhoma.
FusariumsemitectumandF.moniliformedevelopa
fluffywhiteorpinkishcoloration.
C.lunatacoloursthegrainblack.
Symptomvariesdependingupontheorganism
involvedandthedegreeofinfection.

39. FavourableConditions
•Wetweatherfollowingthefloweringfavorsgrainmoulddevelopment.
•Thelongerthewetperiodthegreaterthemoulddevelopment.
•Compactearheadsarehighlysusceptible.
Modeofspread
Thefungimainlyspreadthroughair-borneconidia.Thefungisurviveas
parasitesaswellassaprophytesintheinfectedplantdebris.
Management
•Adjustthesowingtime.
•SprayCaptan1kg+Aureofungin-sol100g/haincaseofintermittent
rainfallduringearheademergence,aweeklaterandduringmilkystage.

40. Phanerogamic parasite -Striga asiatica and Striga densiflora
Itisapartialrootparasiteandoccursmainlyintherainfedsorghum.
Smallplantwithbrightgreenleaves,growsuptoaheightof
15-30cm.
Theplantsoccurinclustersof10-20/hostplant.
S.asiaticaproducesredtopinkflowerswhile.S.densifloraproduces
whiteflowers.
Eachfruitcontainsminuteseedsinabundancewhichsurvivesinthe
soilforseveralyears.
Therootexudatesofsorghumstimulatetheseedsoftheparasiteto
germinate.
Theparasitethenslowlyattachestotherootofthehostby
haustoriaandgrowsbelowthesoilsurfaceproducingunderground
stemsandrootsforabout1-2months.
Theparasitegrowsfasterandappearsatthebaseoftheplant.
Severeinfestationcausesyellowingandwiltingofthehostleaves.
Theinfectedplantsarestuntedingrowthandmaydiepriortoseed
setting.

41. Diseases of pearl millet
Downy mildew -Sclerospora graminicola
Symptoms
Infectionismainlysystemicandsymptomsappearonleaves
(downymildew)andinflorescence(greenear).
Theinitialsymptomsappearinseedlingsatthreetofourleaf
stages.
Theaffectedleavesshowprofusedownywhitegrowth
consistingofsporangiophoresandsporangiaofthepathogen
occurspredominantlyontheundersurfaceoftheleaves.
Correspondingtotheuppersurfaceoftheleaf,yellowingor
patchesoflightgreentolightyellowcolourdiscoloration
occur.
Theyellowdiscolourationoftenturnstostreaksalongveins.
Eachfloretsoftheinflorescenceofinfectedplantsgets
completelyorpartiallymalformedintogreenbeardleafylike
structures,givingthetypicalsymptomofgreenear.

42. Pathogen
The mycelium is filamentous intercellular, hyaline, non-septateand
branched.
The sporangiophoresemerge through stomata singly or in clusters, they are
swollen, short, upright branches bearing sporangia.
Sporangia of Sclerosporashow indirect germination that is zoospores are
produced inside the sporangia and then infect the crop.
Sexual spores are oospores and are thick walled, brown in color and round
shaped
Favourableconditions
Cool (20 -23°C) and moist weather (>90 % RH) favoursthe disease
development
Mode of spread and Survival
Primary spread is by Oospores in soil (viable for 3-4 years) and seed-borne
inoculums, while the secondary spread is through air-borne sporangia.
Pathogen survives as oospores in soil and crop debris

43. Management
•Grow downy mildew resistant varieties CO7, WCC 75, CO(Cu)9, TNAU-
CumbuHybrid-CO9.
•Transplanting reduces disease incidence. At the time of planting, infected
seedlings should be removed.
•In the direct sown crop, infected plants should be removed up to 45 days of
sowing as and when the symptoms are noticed.
•Spray any one of the fungicides Metalaxyl + Mancozeb @500 g or
Mancozeb 1000g/ha.

44. Blast -Magnaporthe grisea
Symptoms
•Thediseaseappearsasgrayish,water-soakedlesionson
foliagethatenlargeandbecomenecrotic,resultingin
extensivechlorosisandprematuredryingofyoung
leaves.
•Thelesionsizevariesfromsmall,roundish,elliptical,
diamondshapedtoelongated,measuring1-2mmto
20mm.
•Lesionsareoftensurroundedbyachlorotichalo,which
turnsnecrotic,givingtheappearanceofconcentricrings.
•Thelesionsareusuallyconfinedtointerveinalspaceson
thefoliage.
•Lesionsgrowandcoalescetocoverlargesurfaceareas
andcausenecrosisoftissues.
•Severelyinfectedplantsproducenograinorfew
shriveledgrainsinblastedflorets.

45. Pathogen
The mycelium is dark brown to olivaceousgreen and septate.
Asexual conidia are pyriform, hyaline, mostly three-celled with a small
appendage on the basal cell.
Through sexual reproduction four celled ascosporesare formed in
perithecium.
Favourableconditions
Prevalence of high humidity (>90% RH) and moderate temperature
(25-30°C) favors infection and disease development.
The disease becomes more severe during humid weather conditions
especially with dense plant stands.

46. Mode of spread and survival
Thepathogensporulatesprofuselyinthelesionsonfoliageandthe
conidiacanbeeasilydispersedbythewindandsplashingrain.
Thesesporescanoverwinterinstubbleandcaninfectthenextcropthe
followingyear.
Conidiageneratedinthediseasedplantcanfurtherspreadtheinfection.
Management
Remove collateral weed hosts from bunds and channels,
Use only disease free seedlings and avoid excess nitrogen.
Seed Treatment with Metalaxyl+ Mancozeb35 SD @ 6g/kg seed
Spray Metalaxyl+ Mancozeb@ 2g/litreafter observing initial infection

47. Rust -Puccinia penniseti/ Puccinia substriata
Symptoms
Symptomsfirstappearmostlyonthedistalhalfofthe
lamina.
Raisedreddishrustypustule(urediosori)appearboth
upperandundersurfacebutappearmoreontheupper
surface.
Thepustulesmaybeformedonleafsheath,stemandon
pedunclesalso.
Later,blackcoloredtelialformationtakesplaceonleaf
blade,leafsheathandstem.
Whilebrownishurediaareexposedatmaturity,theblack
teliaremaincoveredbytheepidermisforalongerduration.

48. Pathogen
Thepathogenisbiotrophic,heterocious,macrocyclicinnature.
Uredinialandtelial,stagesoccuronpearlmillet.
Thespermagonialandaecialstagesareseenonbrinjal(alternatehost).
Uredosporesareoval,elliptic,sparselyechinulatedandpedicellate.
Teliosporesaredarkbrownincolour,twocelled,cylindricaltoclubshaped,
apexflattered,broadattopandtaperingtowardsbase.
FavourableConditions
Closerspacingandrainyweatherfavoursthediseasedevelopment.
PresenceofabundantbrinjalplantsandotherspeciesofSolanumviz.,
S.torvum,S.xanthocarpumandS.pubescentmayresultinseveredisease
spread.
ModeofSpreadandSurvival
Air-borneuredosporesaretheprimarysources.Presenceofalternatehosthelps
inperpetuationofthefungus.
Management
SowingduringDecember-Mayresultsinlessincidence.
Adoptcontrolmeasureswhenthereisrustincidenceintheearlystagesas
spreadofinfectiontotopleavesresultsinpoorgrainfilling.
SprayWettablesulphur2500g/haorpropiconazole@500ml/hawhentheinitial
symptomsofthediseasesarenoticedandrepeatapplication10daysafterif
necessary.

49. Ergot or Sugary disease -Claviceps fusiformis
Symptoms
Honey dew stage:
Thesymptomisseenbyexudationofsmalldropletsofcreamtopink
mucilaginousdropletsof"honeydew"fromtheinfectedspikelets.
Undersevereinfectionmanysuchspikeletsexudeplentyofhoneydew
whichtricklealongtheearhead.Thisattractsseveralinsects.
Ergotstage:
Inthelaterstages,theinfectedovaryturnsintosmalldarkbrownto
blacksclerotiumwhichprojectsoutofthespikelet.
Sclerotiaarelargerthanseedandirregularlyshaped,andgenerallyget
mixedwiththegrainduringthreshing.

50. Pathogen
Thepathogenishavinghighorganspecificitythatisitinfectsonlytheovaryof
thecerealsandentireovaryisconvertedintosclerotiainplaceofnormalseed
developmentfromtheovary.
Thepathogeninfectstheflorets,growsthroughthestylartubetothebaseof
theovarywhereitramifiestheentireovarytissue.
Honeydewsecretioncontainsconidialsuspensionandsurvivesforalong
periodassclerotia
Favorable conditions
Conditions favoring the disease are relative humidity greater than 80%, and 20
to 30°C temperatures during flowering.
Cool night temperature and cloudy weather aggravate the disease.
Mode of spread and survival
The primary source of infection is through the sclerotia.
The secondary spread takes place through air and insect-borne conidia.
Rain splashes also help in spreading the disease.
TheroleofcollateralhostslikeCenchrusciliarisandC.setigerusin
perpetuationoffungusissignificant.Thefungusalsoinfectsotherspeciesof
Pennisetum.

51. Management
Adjust the sowing date so that the crop does not flower during October when
high rainfall and high relative humidity favour the disease spread.
Immerse the seeds in 10 per cent common salt solution and remove the
floating sclerotia.
Remove collateral hosts
Spray Mancozeb 1000g /ha when 5 -10% flowers have opened and again at
50% flowering stage

52. Smut -Moesziomyces penicillariae (Syn: Tolyposporium penicillariae)
Symptoms
Thepathogeninfectsfewfloretsandtransformstheminto
plumpsoricontainingsmutspores.
Thesmuttedgrainsareinitiallybrightgreenlatercolorchanges
todirtyblackincolourcontainingsmutspores.
Thesmuttedgrainsaretwotothreetimesbiggerthanthe
normalgrain.
Maturedsorirupturestoreleasedark-browntoblackspore
ballsofnumerousteleutospores.Relativelysmallproportionof
thefloretsisinfected.
Pathogen
The fungus produces teleutosporesand sporidia.
Teleutosporesoccur in compact, ball-like masses called spore balls in the
infected florets.
Teleutosporesgerminate to produce four-celled promyceliumon which sporidia
are borne in chains.
These sporidiagerminate to cause infection. Two sporidiaof compatible mating
types are needed to form a dikaryoticinfection hypha, which penetrates through
young emerging stigma of a pearl millet floret.

53. Favourableconditions
Smutinfectionandspreadismostfavoredbytheprevalenceofhighrelative
humidity(80-95%)andoptimaltemperature(25-35°C)atthefloweringstageofthe
crop.
Modeofspreadandsurvival
Itsurvivesassporeballsinthesoilthatservesasprimarysourceofinoculum.
Secondaryspreadisbyair-bornesmutspores.
Management
Soilsolarizationtoincreasethesoiltemperaturetokillthesoil-borneteliospores.
Collectsmuttedearheadsinclothbagsanddestructbydippinginboilingwater.
TreattheseedwithCarboxin@2g/kgorCaptan/Thiram4g/kgofseed.
Sprayanyfungicidesviz.,carboxinorcaptafolduringbootstage

54. Head Mold: Various fungi
Symptom
Appearanceofpink,white,brownorgreyfungal
growthwillbeseenongrain.
Apparentlyasymptomaticseedmaybecontaminated.
Manypathogenscausegrainmolds.
Grainmoldsonpearlmillettendtobemoresevere
withhumidconditionsduringgrainfillandifgrain
harvestisdelayed.
Severalfungicausegrainmolds,andthesedifferby
theregionofcultivation,cropmanagement,
environmentalconditionspriortoharvestandstorage
conditions.
Management
Spray mancozeb 1kg/ha or Captan 1kg +Aureofungisol 100g/ha if intermittent
rainfalloccursduringearheademergence,aweeklaterandduringmilky
stage

55. Bipolaris Leaf Spot: Bipolaris setariae
Symptom
Foliarsymptomsvary,asbrownflecks,finelinearstreaks,
smallovalspots,largeirregularoval,oblong,oralmost
rectangularspots
Largefusiformlesionsaresometimesproduced.
Lesionsmayexpandandcoalesce.
Lesionsmaybesoliddarkbrownbutusuallybecometan
orgreyishbrownwithamoreorlessdistinctdarkbrown
border.
Management
Spray mancozeb 1kg/ha.