Forecasting of spotted bollworm earias vitella (Fab.) (Lepidoptera: Noctuidae) Occurrence in Cotton

Spotted bollworm,earias vitella (fab.) (lepidoptera: noctuidae) causes huge losses to cotton crop each year. as a relative hardy species among insects,e. vitella tolerates a wide range of environmental conditions and so is prevalent in many regions of the world. to facilitate predictions of its occurrence in me cotton crop,forecasts were using three years of data collected from pheromone traps and accumulated degree days (dd). moth populations were observed in the second week of august,and in the first and last weeks of september. the dd model predicted that the first,second and third generations of e. vitella produced each year would occur at the accumulation of 2755,3210 and 3665 celsius dd respectively. the predicted dd of population peaks matched closely to observe dd results. these observations were consistent in successive generations with a cycle of 263 celsius dd (predicted) on a yearly average of 241 celsius dd (observed). the capture of 8 moths/trap/night accumulated a range of 2161-2255 dd in the second week of july (equals the minimum etl),whereas,11 moths/trap/night accumulated a range of 2288-2370 dd in the third week of july,accurately predicted the start of application of ipm practices to control this pest. these results enable forecasting of seasonal e vitella population peaks providing additional information vital for development of a successful integrated pest management programme for the spotted bollworm. copyright 2010 zoological society of pakistan.