Comparative efficacy of certain botanicals and bioagents against pod borer, Helicoverpa armigera (Hubner) on field bean, Lablab purpureus (L.).
The occurrence of pod borer commenced from 6th standard week (February second week) with an average population of 0.25 larvae/plant. The pod borer population increased and gradually reached its peak level of 1.35 larvae/plant in 9th standard week (Feb last week) there after declined trend was observed. It was observed that the occurrence of H. armigera might be due to congenial weather factor like temperature, wind velocity, humidity, and sunshine hours prevailed during the investigation. It Was observed that the temperature between 25-35°C favored the multiplication of pod borer whereas, more than 35°C might be attributed to decline of the population. Among the treatments NSKE found superior over all the treatments after first and second sprays, respectively. Among the bioagents HaNPV found superior over other insecticides. Highest population reduction of 15.4% was observed with NSKE. Minimum pod damage was observed NSKE which is followed by Emamectin benzoate 5SG, HaNPV 250LE/ha, neem oil, pongamia seed extract (5 ml/lit), GCKE 0.5%, Bacillus thuringiensis @ 1 kg/ha. Highest cost benefit ratio was recorded in NSKE (1:2.42) and proved to be effective among the treatments.