Younger leaves may lose their green color (chlorosis), curl downwards or become papery white. Older leaves show scattered yellow specks that later develop into irregularly shaped green and yellow patches. The green areas are slightly raised, giving the leaf a puckered appearance. The lesions enlarge and coalesce, and start to die (necrosis). The growth of affected plants is stunted. They produce fewer flowers and pods. Their pods are small, thin and mottled, and sometimes curl upwards. They also contain fewer and smaller seeds.
The virus is transmitted by the whitefly Bemisia tabaci. No seed transmission is possible. The disease occurs in a number of countries in Asia and in Australia. The yellow patches on the leaves considerably reduce plant productivity. Warm temperatures and high humidity favor vector populations. Infection with Mungbean Yellow Mosaic Virus can result in yield losses of up to 100%. The gram yellow mosaic virus affects black gram more often than green gram.
No biological measure can be taken to control viral diseases. However, plant extracts such as neem oils are effective in reducing the population of whiteflies and improving the yield of the infected crops.
Always consider an integrated approach with preventive measures and biological treatments if available. Foliar sprays with cypermethrin, deltamethrin, or dimethoate can reduce whitefly populations. To reduce vectors, border crops (maize, sorghum and pearl millet) can be treated with insecticides.