Impact of ecological factors on incidence and development of tobacco cut worm, spodoptera litura Fabricius on cotton

Abstract

The studies were conducted to ascertain the effect of ecological factors on incidence and development of Spodoptera litura at five different dates of sowing on three varieties of cotton. Sowing dates commenced on 1st February and went upto 1st March with an interval of seven days. The S. litura population was built up progressively from April (1st week) and acquired its peak in the month of May (1st week). Maximum S. litura (25.46%) was built up at temperature ranges from 26.0°C to 35.1°C, relative humidity ranges from 89 and 62 per cent, zero rainfall, wind velocity 6.2 km/hr, total sunshine hours (64.6 hrs/week), evaporation (53.20 mm) and dewfall (0.161 mm). This built up S. litura showed a positive correlation with relative humidity, sunshine hours and dewfall, whereas negatively correlated with wind velocity. The determination of the effects of different weather factors on population and incidence of S. litura in cotton is essential for effective pest management. This study will be very helpful not only in forecasting outbreaks of S. litura but also in formulating effective pest management strategies. © JBiopest.