Development and validation of weather based prediction model for Helicoverpa armigera in chickpea

Weather based prediction model for Helicoverpa armigera was developed and validated using pheromone trap catches data collected in chickpea crop sown on three different dates during 2015-16 and validated for 2016-17. The first catch of male moth of H. armigera was recorded during 1st standard meteorological week (SMW) in early sown crop, while in normal and late sown the first trap catches were noticed during 3rd and 5th SMW respectively. H. armigera adult trap catches then increased gradually and reached their peaks simultaneously during 12thSMW with 32.3, 37.3 and 44.3 moths/trap/week in early, normal and late sown chickpea crop respectively. Male moth population had highest significant positive correlation with maximum and minimum temperature of 2-lag week in early and normal sowing of chickpea. Morning relative humidity and evening relative humidity of current, 1-lag and 2-lag week were negatively correlated with trap catches. The rainfall of 1-lag week and sunshine hours of current week exhibited maximum positive association with male moth population. Weather based prediction models were developed for male trap catches of crop under normal date of sowing and weather factors of current, 1-lag and 2-lag week. By stepwise regression, Tmin, RH1 and SSH were found to be importantweather factors that influenced the trap catches of H. armigera. The pest-weather model was validated satisfactorily with R2 = 0.751, RMSE=2.13%, MBE=-1.08% and MAE= 1.51%.