Studies on Avoidable Losses due to Helicoverpa armigera (Hubner) on Thompson Seedless Grapes

The avoidable losses under field conditions were estimated on cv. Thompson seedless grape during October-March, 1995–96 and 1996–97 at Bolaram, Ranga Reddy District, A. P., India. Helicoverpa armigera (Hubner) can be effectively checked by spraying of fenvalerate 0.01% at 59 DAP (Days after October Pruning) followed by chlorpyrifos 0.05% at 66 DAP, cypermethrin 0.01% at 73 DAP and monocrotophos 0.05% at 80 DAP with a cost benefit ratio of 1:49. The avoidable losses were worked out as 81.06% with the aforementioned spary schedule. In another spray schedule where in the same set of insecticide sprays were repeated in the same order with one week interval, although the avoidable losses stood at 94.40%.,the cost benefit ratio was only 1:28.