PATH 372 Diseases of Horticultural Crops

Survival and spread
P.I: Survives through teliospores in cooler regions and on collateral hosts
S.I: Wind borne Uredospores
Host range: French beans, green gram, black gram and cowpea
Management
Adjust sowing dates to avoid severe infection of plants in the field
Protect the crop with mancozeb or zineb @ 2 kg/ha or wettable sulphur @0.3%
3) Yellow mosaic: Bean Yellow Mosaic Virus, Mungbean yellow virus or Phaseolus
virus-2 (ss DNA virus)
Symptoms
Bright yellow patches appear on leaves. Yellow areas alternate with dark green
areas of the leaf blade.
Younger leaves show more severe mottling and chlorosis.
Leaves completely turn yellow and gradually becomes necrotic
Plants are stunted and flower and pod set is reduced
Pod formation is reduced and if produced, they are deformed having shrivelled and
undersized seeds
Survival and spread
P.I: Collateral hosts
S.I: Whitefly, Bemisia tabaci
Not transmitted by sap, seed and pollen
Host range: French bean, Soybean, Red gram, Xanthium strumarum, Eclipta alba,
etc.
Management
Remove collateral hosts and destroy
Use resistant varieties
Spray metasystox@0.1% for vector control
4) Common bean mosaic virus/ Green mosaic – Bean common mosaic virus (ss
RNA)
Symptoms
Affects only beans (Phaeolus vulgaris & other Phaseolus species)
Symptoms vary according to the variety of bean affected, time of infection and
environmental conditions
Leaves show mosaic pattern, i.e., light green areas alternate with dark green areas.
Diseased leaves become rough, and show blisters on the leaf lamina
Leaf size, petiole length and plant height reduced. Leaves curl downward
Diseased plants produce fewer pods which are smaller in size
Seeds become smaller, malformed and aborted
Survival and spread
Seed, sap, graft and aphid transmissible. Infected seeds are primary means of
spread.
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