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    Introduction

    Diseases and pests represent a majorthreat to the commercial production of

    grapes in the world.

    Climatic conditions are conducive to the

    development of several major grapediseases, including black rot, downy and

    powdery mildew.

    Each of these diseases has the potential to

    destroy the entire crop.

    Most diseases occur simultaneously within

    the same vineyard during the growing

    season.

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    Downy MildewCausal organism

    Scientific Name: Plasmopara viticola

    Symptoms

    Leaves

    oughly circular yellowishdiscolourations called !oil spots".

    #hite fluffy growth primarily on the

    lower leaf surface.

    $s lesions age, they turn brown fromthe centre outward.

    %everely infected leaves may drop.

    Small, circularlesions on upper

    side of leaf

    Downey mildewgrowth on under

    side of leaf

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    Shoots

    &nfected shoot tips curl and covered with whitefluffy sporulation.

    Berries

    #hite fluffy sporulation on small berries.

    May shrivel and drop off.

    %tay hard when healthy berries start to soften atveraison.

    Downey mildew growth

    on berries

    Severely infected

    berriesCourtesy'www. (hioline. osu. edu

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    Biology )he causal fungus, Plasmopara viticola overwinters

    as thick*walled oospores in infected tissues and inthe soil.

    $ minimum of + mm of rain is re-uired for

    oospores to produce sporangia that are dispersed byrain splash to young green tissue.

    )he sporangia release motile oospores that swim to

    the stomates, germinate and infect tissues.

    Disease development is most rapid between /oCand /0oC with fre-uent rain or dew.

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    Powdery mildewCausal organism

    Scientific Name : Erysiphe necator (previouslyUncinula necator)

    1osses in yield of fruits may be upto 2*34. &n addition to loss

    of yield, infected berries tend to be higher in acid content than

    healthy fruits and are unsuitable for wine making.

    Symptoms:

    (n all tissues, powdery mildew looks like a greyish*whitepowder.

    Leaves

    5re-uently first found on the undersides of leaves.

    1esions become apparent on the upper sides of leaves as well.

    (n rapidly growing leaves, infections on the underside may

    cause the leaves to appear puckered on top.

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    %everely infected leaves may become brittle and drop off.

    %tarting as early as late 6uly, very small orange then brownand eventually black spherical structures cleistothecia

    develop on the upper and lower surfaces of infected leaves.

    Shoots

    &nitially greyish*white, develop into brown irregular blotches.

    &ndistinct margins and remain visible after shoot hardening.

    Berries

    7ecome covered in conidia.

    $n initial floury appearance that later becomes dark and grey.

    Dry out and may drop off.

    1ater infections 89*2 weeks post bloom: will have superficial

    greyish scarring.

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    Severe powdery mildewon berries

    Powdery mildew on upperside of leaves

    Severe powdery mildewon cane

    Powdery mildew on underside of leaves

    Courtesy' www.oardc.ohio;grapeipm

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    Black rotCausal organism

    Scientific Name: Guignardia bidwellii

    Symptoms

    Leaves elatively small, brown circular lesions develop on infected

    leaves and within a few days tiny black spherical fruitingbodies 8pycnidia: protrude from them.

    Berries: &nfected berries first appear light or chocolate brown but

    -uickly turn darker brown, with masses of black pycnidiadeveloping on the surface.

    5inally, infected berries shrivel and turn into hard blackraisin*like bodies that are called mummies.

    Shoots under high disease pressure brown to black elongated

    lesions develop.

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    Black rot lesions on

    leaves

    Mummied berriesInfected berry with

    black pycnidia

    Black rot berries

    in cluster

    iny blackpycnidia onleaf lesion

    !longatedlesions on

    petiole

    Courtesy' .

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    "nthracnose#Birds eye diseaseCausal organism

    Scientific Name: Elsinoe ampelina

    &t is especially serious on new sprouts during rainy season.

    $mong various foliar diseases of grapevine in &ndia,

    anthracnose has longest spell spread over the period from

    6une to (ctober

    Symptoms

    Leaves

    &nitially pin*prick dark spots.

    Developing into small round spots with brown or black

    margins with greyish*white centres which drop out causing

    a @shot*holeA appearance.

    %evere infections cause malformed leaves that shrivel up

    and drop.

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    Shoots

    Deep elongated cankers

    Greyish in the centre with a raised dark reddishbrown to violet-black edge

    Infected shoots crack and become brittle

    Berries Reddish circular spots becoming violet with agreyish centre and a raised black edge birds eyerot

    esions can e!tend into the pulp" causing crackingand opening the berry to secondary infections

    #everely infected berries dry up and dropprematurely$

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    Sunken lesions onshoots

    "nthracnose onberry

    Birds eye rot symptoms on berryCourtesy'www.oardc.ohio;grapeipm

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    5usarium #ilt

    $ausal organismScientic %ame& Fusarium oxysporum#ymptoms%

    #hoots and leaves wilt and die in mid-season" with characteristic brown-reddiscolouration of the vascular tissue ofthe a&ected areas$

    eaves drop prematurely and clustersfail to develop and shrivel to mummies$#ymptoms range from one or two shootson a vine to whole plant collapse$

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    Management

    Collect and burn fallen leaves and twigs.

    %anitation of the orchard is highly essential. Clean cultivation of vines or removal and destruction of all

    diseased parts.

    Bine should be kept high above ground to allow circulation of air

    by proper %pacing row resistant varieties like Chholth ed, Chholth white, %kibba

    ed 8

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    ets sum up

    Downey mildew pathogen causes irregular, yellowish,

    translucent spots on the upper surface of the leaves and

    white fluffy sporulation on small berries.(n all tissues, powdery mildew looks like a greyish*white

    powderDue to black rot, infected berries shrivel and turn into hard

    black raisin*like bodies that are called mummies.$nthracnose affected berries shows @shot*holeA

    appearance.