Seasonal incidence of major insect-pests of soybean and their correlation with abiotic factors

Population dynamics of insect-pests of soybean and there correlation with abiotic factors were studied at Norman E Borlaug Crop Research Centre, GB Pant University of Agriculture and Technology, Pantnagar. Observations on the incidence of various insect-pests viz. Spodoptera litura, Spilarctia obliqua, Thysanoplusia orichalcea, Obereopsis brevis, Bemisia tabaci and Melanagromyza sojae were recorded at weekly intervals. On the basis of observations and correlation study of insect incidence in relation to weather parameters, it was found that stem fly having 100% infestation showed significant negative correlation with minimum temperature and its maximum damage (100% infestation, 33.84% tunneling) was highly significant and negatively correlated with the evaporation. S. obliqua incidence was significantly positively correlated with wind velocity. But all the weather parameters were nonsignificantly related to incidence of S. litura, T. orichalcea, O. brevis and B. tabaci. Thus, low temperature and evaporation have negative correlation with incidence of stem fly, whereas, wind velocity was found positively correlated in the case of S. obliqua incidence.