Impact of weather parameters on abundance of major defoliators of soybean

Abstract

Studies were under taken on seasonal incidence and relationship of weather parameters on major defoliators of soybean during Kharif 2014-15 at the College of Agriculture, Nagpur. Incidence of Spodoptera litura began during 35 th standard week (0.20±0.12) gradually attained maximum (1.80±0.11) during 41 st standard week. Multiple regression analysis revealed that decrease in 1per cent of morning relative and evening relative humidity would lead to increase of 0.019 and 0.014 mean number of Spodoptera larvae per meter row length. Incidence of Thysanoplusia orechalsia began during 35 th standard week (0.20±0.15) gradually attained maximum (1.00±0.12) during 42 nd standard week. Population was decreased from 43rd standard week onwards, Regression analysis revealed that decrease in 1per cent of morning relative humidity would lead to increase of 0.010 mean number of larvae per meter row length, decrease in 1°C of morning relative humidity would lead to increase of 2.264 per cent foliage damage.