Neem-based integrated approaches for the management of tea mosquito bug, Helopeltis theivora Waterhouse (Miridae: Heteroptera) in tea

摘要

Despite continuous use of synthetic insecticides during last two decades, the tea mosquito bug, Helopeltis theivora Waterhouse (Miridae: Heteroptera), has become the most destructive sucking pest of tea in North East India. In order to reduce the loadof the synthetic chemicals in tea visa-vis their deleterious effect, integration of biopesticide, synthetic pesticides along with effective spraying strategies, have been attempted. The anti-insect property of "neem", Azadirachta indica A. Juss. (Meliaceae), has been used to solve many pest problems. In this study, different azadi-rachtin concentrations were evaluated at different doses against the H. theivora to find out their controlling efficacy. At 50,000 ppm azadirachtin concentration 65% controlof infestation could be attained, whereas at 3,000 and 10,000 ppm, gave 30-43% reduction and 300 and 1,500 ppm <30% control was possible. Further in case of 3,000 and 10,000 ppm, azadirachtin concentration 30-43% reduction was registered. Therefore, azadirachtin concentration and its dilutions are the major criteria for getting desired bioactivity. Treatments with combined formulations viz. "neem + endosulfan" or "neem + deltamethrin" recorded significant reduction in H. theivora incidence even at reduced doses, as compared to sole application of neem or synthetic insecticide at recommended doses. Effective combinations and dose of the insecticides along with their formulations in controlling H. theivora have been presented and discussed.