AN HOLISTIC APPROACH TO MANAGING EARLY SHOOT BORER CHILO INFUSCATELLUS (SNELLEN) IN SUGARCANE

摘要

Early shoot borer (ESB) has been managed with the insecticide endosulfan, but this has become ineffective and regular, indiscriminate use and sole dependence on this insecticide has caused environmental problems. Alternative methods, such as release of Trichogramma, use of granulosis virus and whorl application of Sevidol, have given encouraging results. In southern India, we investigated the causes of inconsistent performance of the egg parasite Trichogramma chilonis by determining the post-release movement in the sugarcane ecosystem, assessed the impact of intercroping and T. chilonis release on the incidence of ESB, and assessed the efficacy of different IPM strategies against the pest. Most T. chilonis moved 1-5 m from release, and most moved downwind. Of the intercrops coriander, soybean, Dolichos and ladies finger, the best control of ESB and highest activity of T. chilonis occurred in the sugarcane-coriander combination. This resulted in the highest number of millable stalks (113,130/ha), cane yield (92.2 t/ha), cane equivalent yield (105.54 t/ha), and net return (Rs.63,498). In tests of alternative IPM strategies, ESB incidence was significantly less (2.6-7.2%) under strategy 1 (Sevidol, endosulfan and Trichogramma), followed by strategy 2 (granulosis virus and Trichogramma), with the highest pest incidence under successive endosulfan sprays. The highest cost-benefit ration was under strategy 1. We recommend the adoption of strategy 1 to minimise the impact of ESB.