Population dynamics of whitefly, Bemisia tabaci (Gennadius) and its parasitoid, Encarsia lutea (Masi) on Bt cotton under Haryana conditions

Abstract

The present study investigated the population dynamics of whitefly, Bemisia tabaci (Gennadius) and its parasitoid, Encarsia lutea (Masi) on Bt cotton hybrid BIO-6588 (BG II) under unsprayed conditions at Hisar. Peak population of whitefly adults (20.3 whitefly adults/leaf) was observed during 9th to 18th September. Nymphal population (34.1 whitefly nymphs/leaf) and per cent parasitization (28.1%) were observed maximum during 19th to 28th September. Whitefly nymphal parasitization by E. lutea varied from 6.0 to 28.1 per cent during the period of study (June to October). Total rainfall had significant and negative impact on the whitefly adult (r = -0.62) and nymphal population (r = -0.60). All the remaining weather factors showed non-significant correlation with whitefly population. Moreover, no significant correlation was found between parasitization and the weather factors.