Seasonal incidence of cotton leafhopper, Amrasca biguttula biguttula(Ishida) on Bt and non-Bt cotton

摘要

A study conducted at Dharwad indicated the effect of weather parameters and influence of different sowing dates on incidence of cotton leafhopper, Amrasca biguttula biguttula (Ishida) on Bt and non-Bt cotton. Peak population was noticed of 8.40 per three leaves during 45th Meteorological Standard Week (MSW) and lowest population of 0.2 per three leaves was during 7th MSW. The correlation study indicated highly significant negative correlation with minimum temperature, morning and evening relative humidity and rain fall. The crop sown during 1st Date Of Sowing (June 1st, DOS) and last date of sowing, (5th - August 1st, DOS) escaped from leafhopper damage.