Management of whitefly Bemisia tabaci, a vector of tobacco leaf curl virus disease in Virginia tobacco
Tobacco whitefly, Bemisia tabaci is an important pest of tobacco. It causes damage by sucking the sap and as a vector of tobacco leaf curl virus resulting in considerable loss of yield and quality. In the recent past, the incidence of leaf curl virus disease increased in all types of tobaccos in the country. At present management of tobacco leaf curl virus (TLCV) is possible only through control of its vector, whitefly. Continuous decrease in the insecticides that provide adequate control of the pest due to various reasons incited us to evaluate different management modules for minimizing the loss due to the TLCV vector, B. tabaci. Three management modules viz., sorghum barrier crop, chemical control, and integrated (chemicals + barrier crop sorghum) modules along with an untreated check were evaluated for two seasons. Observations were recorded periodically on mean whitefly population, per cent leaf curl infected plants, natural enemies and yield parameters. The mean leaf curl infected plants was least (2 %) at the end of the season in integrated module followed by chemical control module (2.4 - 2.6 %) as against 8.6 - 8.8 % in sorghum border module and 12.4 - 12.6 % in check plots. The data revealed that the mean whitefly population/plant was also found to be significantly less in integrated module followed by chemical control module compared to sorghum border module and check plots. The yield parameters viz., cured leaf, bright leaf and grade index were also higher (2655, 1575 kg/ha & 1965) in integrated module and chemical control module (2620, 1545 kg/ha & 1888) compared to sorghum border module (2370, 1410 kg/ha & 1650) and check (2053, 1165 kg/ha & 1490). It is evident that integrated module could effectively protect flue-cured Virginia tobacco from leaf curl virus disease transmitted by whitefly.