Interaction of Abiotic Factors on Population of Insect Pests and its Natural Enemies in Bt and Non Bt Cotton Bhanderi G. R., Patel R. D., Desai H. R., Sandipan Prashant, Solanki B. G. Department of Entomology, Main Cotton Research Station, Navsari Agricultural University, Surat-395007 Online published on 2 January, 2017. Abstract Field trial was conducted to determine the effect of ecological factors on the incidence of insect pests on two hybrids of Bt and one non Bt cotton. Sucking insect pest viz. leafhopper, whitefly, thrips, aphid and mealybug remained active throughout the crop season with little differences among them and between Bt & non Bt version. Sucking pests was active from 31st to 52nd SMW (SMW i.e. July to December). The peak population of aphid was observed in 48th SMW while leafhopper population reached to peak in 36th SMW. The higher population of thrips was observed in 32nd SMW while, whitefly incidence started from 33rd SMW and remained below ETL during the season. Mealybug was found from 42nd to 52nd SMW. Predators of pests, lady bird beetle and Chrysoperla observed from 33rd to 52nd whereas spiders population started from the 31st to 52nd SMW. The correlation between predators (LBB and Chrysoperla) and aphid was found highly significant and positive. Aphid, whitefly and mealybug population were highly significant andnegatively associated with minimum temperature and morning RH. Leafhopper showed significant positive correlation with minimum temperature and morning RH. Thrips population was highly significant and negatively correlated with maximum temperature and sunshine hours while it was positive correlated with minimum temperature, morning RH and evening RH. The bollworms were active 38th to 48th SMW but population of H. armigera; E. vittella and S. litura were peak in 43th, 45th and 41th SMW, respectively on non Bt version (DCH 32). The incidence of S. litura was almost nil throughout the season on RCH 2 BG I. Negligible population of H. armigera and E. vittella was observed on RCH 2 BG I but peak population was recorded in 43rd and 46th SMW, respectively. Incidence of Spodoptera was almost nil throughout the crop period in RCH 2 BG I. On RCH 2 BG II, the incidence of H. armigera; E. vittella and S. litura was almost nil throughout the season. Pink bollworm larvae and damage were observed early in 38th SMW and continued till crop end on both Bt and non Bt version. E. vittella larval population showed negative and highly significant correlation with sunshine hours. The pink bollworm larval population showed positive correlation with maximum temperature. Moth catches of H. armigera and P.gossypiella showed highly significant and negative correlation with minimum temperature and morning relative humidity whereas; E. vittella showed significant negative correlation with maximum temperature. S. litura moth catches showed highly significant and positive association with maximum temperature Top Keywords Abiotic factors, Bt Cotton, Non Bt Cotton, Insect pests, Population dynamics, LBB, Chrysoperla, Spider, SMW. Top |