Diseases of Peach.pdf

Diseases of Peach

1. Siddu Lakshmi Prasanna
Course No.: PATH 2.7.1.
CourseTitle:DiseasesofFruit,Plantation,Medicinal
andAromaticcrops
By
Dr. SidduLakshmi Prasanna
Ph. D (Agri.)
Dept.ofPlantPathology

2. Peach
Sr.
No.
Disease Causal organism
1.Leaf curlTaphrinadeformans
2. RustPucciniapruni-spinosaevar.
discolor
3. ScabCladosporiumcarpophilum
Scientific name: Prunus persica
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3. Minor diseases
1.Powderymildew–Sphaerothecapannosavar.persicae
2.Brownrotoffruits–Moniliniafructicola,M.fructigena,M.laxaf.sp.mali
3.Frostymildews–Cercosporellapersicae
4.Targetleafspot–Phyllostictapersicae
5.Bacterialleafspot:Pseudomonassyringaepv.persicae
6.Gummosis:Prunusdwarfvirus
7.Mosaicvirus
8.NecroticLeafspot:virus
9.Peach-X:Phytoplasmalikeorganism
10.Peachyellows:Phytoplasmalikeorganism
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4. SYMPTOMS:
➢Thediseasefirstappearsintheearlyspringasthe
leavesbegintounfold.
➢Theleafbladethickens,puckeredalongmidrib&curl.
➢Leaves2-3timeslongerthanhealthyanddevelopred
orpurplecolour.
➢Puckeredpartsofleafmayturnyellowishandthen
greyichwhite,asvelvetysporesareproducedonthe
surface.
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5. ➢Finallyleafturntoreddishpurpletint.
➢Thereddishvelvetysurfaceoflaminaissooncoveredwithawhitish
greybloomofthefungusontheuppersurface.
➢Boththeleaves&petiolemaycurl.
➢Affectedleavesdie&dropimmaturely.
➢Twigsbecomepalegreentoyellow,swollen,stunted&exudegummy
materialanddie.
➢Flowersandfruitsarealsoinfected&dropprematurely
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6. Etiology:
•Myceliaareintercellularanditdoesnotproducespecificascocarp.
•Asciareproduced(Openascus)individuallyandmeasure25to40into8to11micro
meter.
•Eachascusbearseightascosporeswithadiameterof3to7micrometer.
Epidemiology:
•Thediseaseisprevalentinareaswherecoolmistspringweatherprevailsandthedry
hotweatherhastensdefoliation.
Primarysourceofinoculum:Fungusoverwinterasascosporesorasthickwalled
conidiaonthebudscalesorasperennialmycelium.
Secondarysourceofinoculum:Airborneascospores/conidia.
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7. Management:
•Removal&burningofinfectedshootsreducethespreadofthedisease.
•AdormantspraywithBordeauxmixture(1%)withanadhesive&awinter
spraywithBordeauxmixture1%beforebudburstcontrolsthedisease.
•Sprayingofcopperoxychloride0.3%orcarbendazim0.1%orchlorothalonil
0.1%eitherbeforebudswellinsprayingoraftergeneralleaffallinautumn.
•ResistantvarietiesRedheaven,favorite,modelinepouyet.
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8. Symptoms:
➢Paleyellowspotsappearonboththesurfacesofthe
leaves.Laterthespotsbecomebrightyellow,
angularspotsfromthetopandblisterswithrusty
sporesonthebottom.
➢Leafcankersturnnecrotic,causingleafdropand
earlybloominwinter.
➢Affectedleavesremainingonthetreecontain
overwinteringstructuresthatallowinfectionin
spring.
Rust
Causal organism:Puccinia pruni-spinosae var. discolor
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9. Siddu Lakshmi Prasanna

10. ➢Symptoms on young stems: starts as water
soaked lesions, develop into splits with uredinia
formation.
➢Twig cankers appear as blisters, with splits
measuring upto¼ inch long usually visible on
the upper side of the twig.
➢After the twig lesions emerge, rusty brown,
powdery masses of spores (urediniospores) are
produced in the cankers.
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11. ➢Fruits-Onimmature,yelloworgreenfruit,lesionsdevelopassmall,
brownishspotsabout0.1inchdiameterwithgreenhalos.
➢Whenthefruitmaturesanddevelopsdarkerskincolour,theselesionhalos
becomegreenishyellow.
➢Thelesionsaresunkenandextendseveralmillimetersintothefruit.
➢Numerousinfectionsmaydeveloponeachfruitandthesecanleadto
secondaryinfectionsbyotherfungalspeciesandcausefruitdecay.
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12. Primarysourceofinoculum:
•SurvivesasperennialmyceliumintheundergroundstemsofAnemonecoronaria
(alternatehost)onwhichthefungusproducesitsaecialstage.
•CanalsosurviveasUredosoriontwigs.
Secondarysourceofinoculum:windborneUredospores
Etiology:
•Thefunguspersistsasperennialmycelium,intheundergroundstems.
•Thebasidiaproducedonthisplantduringspringinfectpeachleaves.
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13. Management:
•Destructionofalternatehost
•Cut&burntheaffectedleavesorplantpart.
•Spraywithzineb0.2%ordustingwithwettablesulphur.
•Sprayingofergosterolbiosynthesisinhibitorslike
propiconazoleormyclobutaniletc.
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14. SYMPTOMS:
➢Thediseaseoccursonfruit,twigs&
leaves.
➢Leaves-infectionsappearas
inconspicuouschloroticyellowspotson
thelowersurface.Whenthenecrotic
tissuefallsout,shotholesappearon
leaves.
SCAB /freckle /black spot
Causal organism: Cladosporium carpophilum
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15. ➢Onthetwigs,lightbrownovallesionsareformedwhich
enlarge&turndarkbrown.
➢Darkbrown,long&narrowlesionsarenoticedonthe
midrib.
➢Circular&dark–olivaceouslesionsappearonfruits.
➢Insevereinfectiontheindividualspotsmerge&forma
uniform,darkolivaceous,velvetyblotch.
➢Athickyorcorkylayerofcellsisproducedbelow
surfacethescabbedregion.
➢Thefruitbecomesabnormalinshape&cracks.
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16. Diseasecycle
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17. Etiology:Dormantmycelia,septatemycelia
Primarysourceofinoculum:
•Fungusoverwintersinlesionsontwigs.Conidia,myceliumandchlamydosporesfor
itsdispersalandsurvivalstructures.
•Dormantmyceliainfallenleaves.
Secondarysourceofinoculum:spiloceatypeofconidia(airborne)orwatersplashes.
Infectiontakesplaceinbetweenthecuticle&epidermis.
Epidemiology:
•9hourofleafwetnessperiod,17-18°Ctemperature,susceptiblehost.
•Infallenleavesif200-300pseudotheciapresent&leafwetnessis9hour,single
pseudotheciaproduces800-900ascospores.
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18. Management:
•Cut&burnaffectedplantpart.
•Low-lyingfieldsshouldbeavoidedforcultivation.
•Treeshouldbeproperlyprunedtopermitfreeaircirculation.
•Timelyapplicationofthestandardfungicidesprayscontrolsthescab.
•Sprayingof5%ureasolutiontothefallenleaves.
•Chemicalspraywithschedulingtimeslike:
a)silvertiptogreentip-mancozeb4g/liter,b)Pinkbudstage-carbendazin@1g/liter.
c)Petalformstage-Bittertenol,d)Fruitstage-(peanutstage)–capton3g/liter
e)40daysbeforeharvest–hexaconozole1.5g/liter.
•Biologicalagent’slike-Altheliaspecies,Chaetoniumglobosum.
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