Sucking insect-pests incidence in relation to weather parameters under Bt cotton in Northwestern region of Punjab, India

The present study was conducted to investigate the effect of weather parameters on occurrence of sucking pests in Bt cotton. The incidence of thrips (Thrips tabaci), whitefly (Bemisia tabaci), leafhopper (Amrasca biguttula biguttula) and aphid (Aphis gossypii) was observed in 20th Standard Meteorological Week (SMW). Maximum population of whitefly, aphid and thrips was found in 26th SMW whereas, highest incidence of leafhopper was recorded in 28th SMW. Later on, another two sucking pests viz., dusky cotton bug (Oxycarenus laetus) and red cotton bug (Dysdercus cingulatus) were recorded in 34th SMW and acquired peak population in 37th SMW. Correlation analysis revealed that significant positive correlation was found between maximum and minimum temperature and population of whitefly, aphid, thrips and leafhopper while, significant negative correlation was observed with population of red cotton bug and dusky cotton bug. On the other hand, rainfall and relative humidity exhibited significant negative association with the incidence of whitefly whereas, population of aphid, thrips and leaf hopper showed non-significant negative correlation.