Studies on leaf curl disease of sesamum

Abstract

Leaf curl disease of sesamum, its symptomatology, mode of transmission, vector-virus relationships, the pattern of spread under field conditions and the extent of loss caused by the disease were investigated. Major symptoms of the disease were abaxial curling of the leaves, thickening of the veins on the under surface of the leaves, leathery appearance of the leaves and reduction in the size of leaf lamina. The plants remained stunted and produced few flowers and pods when infection occurred during the early stages of the plant growth. When infection occurred during later stages there was production of flowers and pods hut to a limited extent. This particular virus could he transmitted by wedge and side grafting and by the whitefly Bemisia tabaci Genn. The minimum, acquisition feeding period was found to be 10 min and the minimum inoculation feeding period was 20 min. The vector required an incubation period of 28 h to become viruliferous. Even a single whitefly was found to be capable of transmitting the virus. Once the vector acquired the virus it would retain it till its death. Negative results were obtained in the case of sap and seed transmission showing that this particular virus was not sap and seed transmissible.