Incidence of yellow vein mosaic virus disease of okra [ abelmoschus esculentus (l.) moench ] under summer and rainy Environments

Okra or bhindi [ Abelmoschus esculentus (L.) Moench ] is an important Vegetable crop in the tropics and the subtropics. The Okra crop is very susceptible to white fly (Bemisia tabaci Genn.) transmitted yellow vein mosaic virus causing heavy losses by infecting at all the stages of plant growth. In India, occurrence of this disease was first reported by Kulkarni (1924) in Bombay province. It has been reported that when plants were infected within 20 days after germination, the losses can be up to 98 percent. Similarly, when plants were infected at 35 and 50 days after germination, the loss in yield was 83 and 49 percent respectively (Sastry and Singh, 1975). Infection of Y.V.M.V. under natural field conditions depends on the environmental parameters, crop characteristics and efficient vector population (Khan & Mukhopadhyay, 1986; Bhagabati and Goswami, 1992). Susceptibility of cultivars encourages its incidence in the field in presence of the active vectors. Considering it as one of the major constraints of Okra cultivation, it is essential to gather basic information to understand the nature of infection, source and gradual increase with the increase of plant age survival capacity of the virus and mode of spread among different varieties in a cropping season.