Population dynamics of whitefly, Bemisia tabaci (Gennadius), as influenced by weather conditions infesting Bt cotton hybrid

To quantify the effect of different sowing environments and weather conditions on incidence of whitefly on cotton, experiments were conducted at PAU Regional Research Station, Bathinda during kharif 2014-2017) with Bt cotton hybrids 'NCS-855 BGII' at normal and late sowing. The mean incidence of whitefly was ranged from 0.0–39.5, 11.2–124.0, 0.2–26.4 and 0.7–15.5 adults/leaf during 2014, 2015, 2016 and 2017, respectively. The maximum adult population of whitefly was recorded in month of August almost in all the years, having its peak between 31–34 standard meteorological weeks (SMW). Among years, whitefly population was negatively correlated with rainfall, morning and evening relative humidity, while positively correlated with maximum temperature (except 2014) and minimum temperature (except 2014 and 2017). Moreover, bright sunshine showed positive correlation with whitefly population. In respect of pooled data, whitefly population showed negative correlation for minimum and maximum temperature and rainfall, while, positive correlation with morning and evening relative humidity and bright sunshine hours. Overall, crop sown at normal date was less affected by infestation of whitefly than late sown crop. So, this information would be helpful in developing efficient pest management strategies on cotton crop in order to get good harvest.