Spodoptera litura: An Emerging Pest on Bt Cotton (Cry 1Ac) under North Indian Conditions

The results of field survey carried out in 14 villages in Sirsa district (Haryana) indicated increasing trend in the population of Spodoptera litura (Fab.) from 1.36±0.96 ((ange 0.30–3.47) in 2004 to 2.43±2.0 (range 0030-7.35) per plant in 2005. The field experrments conducted on natural infestation of Bt and non Bt cotton hybrids revealed that the incidence of S. litura on Bt cotton initiated in 38^th and 35^th Meteorological Standard Week (MSW) in 2004 and 2005, respectively. The population reached maximum of 1.50 larvae per plant and 0.9 larva per plant in RCH-134 Bt and Ankur 651 Bt on 40^th and 38^th MSW during 2004 and 2005, respectively. The difference between the incidence of S. litura in Bt cotton (Bollgard I - Cry 1Ac) (0.25–0.28 larva per plant) and non Bt cotton (0.10–0.28 larva per plant) remained statistically non significant.