Disease of pumpkin
There are many disease attacks in pumpkin farming, pumpkin farmers are very disappointed from these disease, so in this article we understand the disease attack in pumpkin farming, there symptoms, and how to control them.
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List of diseases :-
- Gummy stem blight (GSB)
- Anthracnose
- Cucumber mosaic virus (CMV)
- plectosporium blight
- Sclerotinia stem rot
- Bacterial wilt
Pumpkin diseases causes,symptoms and there control :-
1. GUMMY STEM BLIGHT (GSB) :-
Gummy stem blight is a major disease of many cucurbit.
The pathogen may be present in and on the cucurbit seed.
Planting seed from infested fruit can cause GSB.
Disease development is favoured by the high humidity and warm conditions.
Caused by fungus stagonosporopsis cucurbitacearum.
SYMPTOMS :-
The most typical symptoms is a water - soaked lesions on the hypocotyl where the cotyledon attach.
Necrotic spots may also be present on the margins of cotyledons.
Young seedlings may be infected but not show any symptoms until they are a few weeks old.
Leaves :- water soaked, circular to irregular dark brown spots,
Spots may tear and drop out giving the leaves tattered appearance.
Stems/vines :- water soaked lesions and cankers develop on the stem,
They are at first pale brown.
A raddish gum oozing from cracks of cankers, which gives the disease its name.
Black, pimple like fungal fruiting bodies are often visible in the cankers.
Severe cankers can girdle the stem causing wilting and eventually death of the vines.
Fruit( black rot ) :- dark, sunken, water soaked spots ( known as black rot ).
These spots expand, can produce gummy exudate.
Internal rind can become black and deeply wrinkled.
CONTROL :-
Cultural Method :-
Use disease free seeds.
Crop rotation with non cucurbit crops is must.
Manage irrigation, control pest and weed, remove and destroy all plant debris from infected crops.
CHEMICAL CONTROL :-
1. TATA MASTER = Active Ingredients :- Mancozeb + metalaxyl
Tata Master Is a systemic and contact fungicides that controls various fungal diseases.
2. CUSTODIA :-
active ingredients :- azoxystrobin + tebuconazole
Used to control a wide range of fungal diseases in crops.
3. CHLOROTHALONiL :-
contact fungicide.
Used as preventives.
2. ANTHRACNOSE :-
Seed born disease.
Anthracnose causing fungi require water to disseminate and infect, they can't spread in dry conditions.
Leaves :- dark water soaked circular or irregular lesions or spots appear on leaves.
These can inlarge and merge, sometimes with a yellow halo around them.
Shoot and twigs :- sunken lesions or cankers, can form on stem and twigs.
Killing off new growth and causing dieback.
Fruits :- dark, sunken spots and blotches appear on fruit.
A pink or orange, jelly - like mass of fungal spores may visible in the centre of the spots during moist conditions.
Flowers and Buds :- the disease can cause flower blight and kill buds.
Overall plants :- severe infection can lead to premature leaf drop, dieback of branches, and stunted growth.
Conditions that favour the disease :-
Wet and warm weather :- the fungi that cause anthracnose grow best in warm, wet and humid environment, especially during periods of heavy rain.
High humidity :- densely planted areas with poor air circulations can trap moisture, creating an ideal microclimate for the fungus.
Overwintering :- the fungus can survive the winter in infected plant debris, such as fallen leaves, twigs and mummified fruit.
PREVENTION :- Remove and destroy infected plant material.
Plant resistant varieties.
Proper spacing between plants to plants.
Can't do overhead irrigation.
Crop rotation is must.
Prune infected branches and lower leaves to increase air circulation and remove disease sources.
CONTROL :-
Chemical Control :-
Use of copper based fungicides :- these are broad spectrum fungicides.
Effective against anthracnose in many crops, including cucurbits.
Mancozeb :- used as preventives.
Azoxystrobin :- systemic fungicides that is high
ly effective and long lasting protection.
3. CUCUMBER MOSAIC VIRUS (CMV) :-
cucumber mosaic is the most destructive and widespread disease of cucumber and muskmelon and all cucurbit family.
Symptoms :-
cucurbits plant may becomes infected at any stage of growth, from emerging of the seedling to near maturity.
external symptoms may develop within four or five days after young plants become infected, but may take up to 14 days to develop when the foliage is older and more mature.
symptoms develop more rapidly at 26-32 degree celcius.
cucurbit plant rarely become infected in the seedling stages, when this happen the cotyledons may turn yellow and wilt.
new leaves are slightly mottled a yellowish green, remain small, wrinkled, and distorted.
when vigorous wine crops become infected in the 6-8 leaf stage the symptoms 1st appear on the youngest, still expanding leaves.
leaves are often stunted, distorted, wrinkled and curld downward.
vines are sometimes dwarfed and may be yellowish near the center of the hill and 'bunchy'.
when a plant becomes infected in midseason, previous growth remains normal and produces healthy fruit.
all leaves, petioles, and stems formed after the first symptoms appear are dwarfed, such plant produces few fruits.
Disease Spreading Cycle :-
CMV is usually introduced into cultivated vine crop fields and gardens by more then 60 species of aphids, after they pick up the virus by feeding on reservoir hosts for a few seconds to a minute.
Primary infections can also occur from mechanical inoculation, in greenhouse by workers hands.
Plant Susceptible Of CMV :-
Alfalfa, Cucumber, Banana, Beans, Buck Wheat, Cabbage, Carrot, Cloves, Corn, Gladiolus, Gouds, Lettuce.Merigold, Mints, Muskmelon, Onion, Pea, Peppers, Pineapple, Potato, Pumpkin, Rye, Safflower (used for oil production), Spinach, Sweet Potato, Tomato, Turnip, Watermelon, and wheats.
CONTROL :-
there is no effective chemicall for the cure of CMV, once a plant is infected with this.
For controlling CMV we need to control aphid vectors that spread the viruses.
first we use IPM for controlling, then use chemicall control, if IPM not works.
Aphid can spread the virus almost instantly, before an insecticides has a chance to kill them.
Common insecticides use to control aphid vectors includes :-
IMIDACLOPRID.
THIOMETHOXAM
DIMETHOATE
CYPERMETHRIN
BIFENTHRIN
4. PLECTOSPORIUM BLIGHT :-
Plectosporium blight caused by the fungus Plectosporium tabacinum (also known as microdochium tabacinum and fuserium tabacinum).
the fungus caused 50-85% fruit loss.
Symptoms :-
Affected plants are small; diamond - shaped, white to cream colored lesions on the stem and on the underside of the leaves.
Affected fruits also exhibit raised, circular, white to cream colored lesions.
As the disease progresses, the infected stems become very brittle often leading to breakage.
the lesions on the fruits can allow the entry of pathogene, that harm the fruit quality and fruit may rot.
Favourable Conditions For Fungus Growth :-
the fungus survives in soil and on decaying plant materials for several years (almost 3 year).
Spores are primarily dispersed by wind and rain splash.
The disease is highly dependent on environmental conditions, with warm wet and humid weather favouring its development and spread.
CULTURAL CONTROL :-
Crop Rotation :- three year crop rotation will be done.
Scouting :- the disease is easily diagnosed by naked eyes, so scout the field regularly.
proper spacing and air circulation between plants will be maintained.
CHEMICAL CONTROL :-
Some chemicals are available for its control, such as :-
Chlorothalonil (available in the market as Bravo, Daconil, Kavach, etc.), these are highly effective contact fungicide.
Dithiocarbamates.
5. SCLEROTINIA STEM ROT or WHITE MOLD :-
Sclerotinia atem rot (sclerotinia sclerotiorum), also known as white mold.
If environmental conditions are favorable and infection occurs at early flowering,
yields can potentially be reduced by at least half.
SYMPTOMS :-
Areas of brown to gray discoloration are found on leaves and stems, especially around the leaf axils.
infection on the stems, resulting from infected leaf axils, expand and turn grey - white in color.
Premature ripening and wilting.
weakened stems that break easily plants can lodge causing the stalk to bend.
premature death of the plant, if infection occurs in the main stem.
black resting bodies are produced inside the bleached area of infected stems, after infection is established.
Fluffy white cottony fungal growth is a key sign, especially under humid conditions.
Hard, black, irregular shaped structures called sclerotia form on and inside the infected plant tissues.
CULTURAL PRACTICES :-
crop rotation :- 2-3 years
Deep plowing :- deep ploughings can buried sclerotia below top 2 inches of soil, preventing apothecia formation.
use wide row spacing and lower plant populations to promote air circulation.
CHEMICAL CONTROL :-
Carbendazim :- used as seed treatment or a foliar spry.
Nativo :- active ingridients = tebuconazole + trifloxystrobin
propiconazole
Precautions :-
Foliar Spray :- applied at the time of disease initiation or during the flowering stage of the crop,
Seed Treatment :- treating with fungicides like carbendazim, or carbendazim + mancozeb.
Soil Drenching :- using tebuconazole + trifloxystrobin.