BEMISIA TABACI BIOLOGICAL AND LIFE TABLE PROPERTIES ARE AFFECTED BY BT AND NON-BT COTTON CULTIVARS (GENNADIUS)

Abstract

Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is a common cotton pest that causes massive economic losses yearly, directly or indirectly. This study aimed to investigate the effects of Bt cotton on the biological and life table parameters of B. tabaci under controlled conditions.The incubation, nymphal, and pupal periods were recorded as shortest on Bt and longest on non-Bt cultivars. It completed immature stages within 27.8, 28.2, and 28.6 days on Bt, whereas it took 30.4 days on the non-Bt cultivars. Adult longevity increased in Bt cultivars while decreasing innon-Bt cultivars. The male lived for a shorter duration and was smaller than the female. Pre-oviposition was higher in non-Bt cultivars and lowered in Bt cultivars. Bt cultivars had longer oviposition periods than non-Bt cultivars. Fecundity was relatively higher on Bt (57.5, 55.1, and54.2 eggs/female) but reduced on non-Bt (48.2 eggs/female). The life table parameters were also modified using different cotton cultivars. Age-survivorship declined with age, and the highest mortality was recorded at the egg stage, with non-Bt having a longer life span than Bt cultivars. In the egg stages, life expectancy was similarly greater. The net reproductive rate (RO) was recorded as the highest, and the intrinsic rate of increase (rm) was the lowest on Bt cultivars. Non-Bt cultivars had the highest finite rate of increase, mean generation time, and population doubling time, while Bt cultivars had the lowest. The experimental findings showed that Bt was slightly more suitable for developing B. tabaci than non-Bt cultivars.