author(s)
Amit Kumar, Dalip Kumar, Krishna Rolania, Deepika Kalkal, Lomash Kumar and Vivek Kumar Saini

abstract
Present study was carried out during Kharif 2018 to know the changes in population of whitefly adults as well as nymphs in weedy and non-weedy habitats. The transgenic hybrid cotton variety RCH 650 was sown in first fortnight of May, 2018 with a spacing of 100×45 cm and replicated four times in both non-weedy and weedy habitats. Mean adult population (adults/leaf) peaked twice during the study i.e. in 29^th (8.01 and 8.82/ leaf) and 35^th SMW (8.96 and 10.89 / leaf) whereas, whitefly nymphs peaked in 34^th SMW (20.12 and 23.21/leaf) in non-weedy and weedy habitat respectively. White fly population (nymphs and adult) presented a non-significant positive correlation with temperature and relative humidity. Adult population in non-weedy habitat was significantly negatively correlated with rainfall (r = -0.502) and wind speed (r = -0.515) whereas nymphal population showed non-significant negative correlation. Regression analysis revealed that influence of weather parameters was high and significant on whitefly adults (R²=0.86) and nymphal (R²=0.57) population.