Studies on the mosaic disease of snake gourd (Trichosanthes Anguina L.)

Abstract

The symptom of snake gourd mosaic disease manifested as mosaic pattern with dark green raised blisters on the leaf lamina. The size of leaves severely reduced ; internodes shortened and the growth of the plant is retarded. The infected plants blossom sparingly and set few fruits. The virus is sap and insect transmissible; both Aphis gossypii and A cracdvora transmitted the virus. Studies on the vector-virus relationships with A. cracdvora showed that the vector could acquire the virus with 5 minutes acquisiton feeding and transmit it with 5 minutes feeding on a healthy test plant. A minimum of 5 aphids are required for transmission and pre-acquisition starvation increased the efficiency whereas pre-infection starvation beyond 30 minutes ^uucod it. The vector could met retain the virus for long periods and the relationship was of non-persistent nature. The physical properties of the virus are: T.!. P. of 70 -75°C, D.E.P. ,of 1 '.5000-1 :1 0000, longevity in vitro of 72-96 hours at room temperature and 144—168 hours at "lOt). Eight species of plants in 3 families ^c susceptible to infection by the virus. Based on the above characteristics, the virus causing mosaic disease of snake gourd in Kerala is identified as a strain of ucumis virus 1 .