Population dynamics of sucking insect pests of cotton and its correlation with abiotic factors.

The research was conducted during kharif seasons of 2008 and 2009. Nineteen genotypes comprising of seventeen Bt hybrids, one conventional hybrid and one variety were evaluated for their reaction to sucking insect pests, under unsprayed condition. Observations on sucking pests were recorded at weekly intervals. The highest population of leafhopper was recorded during 28th and 32nd standard weeks. The highest mean incidence was recorded in H-1226. Whitefly population remained below economic threshold level (ETL) during 2008 while during 2009 it crossed ETL in RCH 134 BG-II (6.00-6.23 adults/leaf). Mean highest population was recorded in IT-905 Bt and RCH-134 BG-II. Leafhopper and whitefly population were significantly and positively correlated with temperature while negatively correlated with rainfall. Among the genotypes, it was observed that there was no significant difference in population of the sucking pests.