Comparative efficacy of indigenous plant extracts and a synthetic insecticide for the management of tomato fruit worm (Helicoverpa armigera Hub.) and their effect on natural enemies in tomato crop

摘要

Efficacy of five botanical extracts (eucalyptus, bakayan, chilli, thyme and onion extract) and synthetic insecticide (Steward 150 EC) was evaluated against H. armigera and its associated natural enemies under field conditions during 2014, followed Randomize Complete Block Design with three replications. Results revealed that all the tested botanicals and insecticide were found effective in controlling the tomato fruit worm infestation as compared to control. Among all the tested spray materials, Steward 150 EC was found the most effective in reducing H. armigera larval infestation (61.01%) followed by bakayan extract (44.49%). However, the steward 150 EC was comparatively more toxic to the natural enemies than botanicals. Fruit infestation was minimum in Steward tested plots and maximum in control on weight basis and on number basis 10.53% and 10.29% and 30.88% and 29.11% respectively. Similarly, Steward treated plot yielded the highest (9564 kg haSUP-1/SUP) and control yielded the lowest (5487 kg haSUP-1/SUP). It was concluded that Steward 150 EC was the most effective in managing fruit worm infestation and hence resulting the minimum fruit damage and consequently enhanced the yield of tomato. However, the synthetic insecticide was extremely toxic to the natural enemies. Furthermore, eucalyptus, chilli, onion and thyme extract also showed better results than control in term of pest reduction and were comparatively safe to the natural enemies, Hence these botanicals should be included in IPM program for the suitable management of H. armigera associated with tomato crop.