Determination of economic injury level for Helicoverpa armigera Hubner on Bt cotton

摘要

A field experiment on determination of economic injury level for Helicoverpa armigera on Bt cotton hybrid (NCS 145 BG I) was conducted in nylon net house for two consecutive years (Kharif, 2008 and 2009) at Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, H. armigera 3rd instar larvae (@ 1 to 5/ plant) were released at 90, 110 and 125 days after germination in separate sets of experiments. The results indicated that the damage potential of 0.96 to 1.69 and 1.80 to 3.08 per cent of green fruiting bodies/larva with survival up to 28 to 34 and 28 to 36 days after release during 2008- 2009 and 2009-2010 was noticed, respectively. An average EIL of 2.71 larvae/ plant for H. armigera was worked out on Bt cotton.