Impact of Weather Parameters on Incidence of Bollworm Complex in Cotton

A field experiment was conducted during 2004–05 and 2005–06 crop season to study the impact of weather parameters on incidence of bollworm complex in cotton. Spotted bollworm was recorded in 29^th standard week and remained active up to 47^th standard week with maximum incidence (12%) in 39^th standard week. Incidence of American bollworm was observed in 32nd standard week and continued up to 4^th standard week, with peak incidence (11.8%) in 44^th standard week. Pink bollworm incidence started from 38^th standard week and continued up to 4^th standard week with peak in 47^th standard week. Maximum and minimum temperature showed strong positive association with spotted bollworm incidence. American bollworm incidence had strong positive correlation with maximum temperature while negative with relative humidity and rainfall. Pink bollworm incidence had strong negative correlation with minimum temperature, relative humidity and rainfall. About 31.13, 36.63 and 43.22 per cent variation in spotted bollworm, American bollworm and pink bollworm incidence, respectively were explained by weather parameters.