Tomato leaf curl virus disease (TLC) was checked by frequent and early applications of Anthio, Folimat, Malathion and Phosdrin against the aleyrodid vector, Bemisia tabaci. Conversely, up to two-fold increases of fruit yield resulted from such applications of the insecticides. Though seed-bed or field applications, separately, gave satisfactory results on occasions, treatments of the plants in the seed-bed and the field were often both essential. Field observations during the experimental period, over four consecutive seasons, showed peak infection rates within the first 8–12 weeks of tomato planting. There were marked inter-seasonal fluctuations of disease incidence, ranging from < 50 to 100 per cent. There was no clear correlation between spread of the disease and the wind direction. Epidemiological behaviour of the disease is discussed in relation to its chemical control.