IMPACT OF BT COTTON ON INSECT BIODIVERSITY IN COTTON ECOSYSTEM IN INDIA

Biotechnology in general and insect-resistant transgenic crops in particular has played a significant role in reducing crop losses caused by insect pests. The commercialization of Bttransgenic cotton in India has significantly increased the cotton production from about 10 million bales in 2001-2002 to 34 million bales in 2009-2010. The deployment of Bt cotton in India has significantly reduced the numbers and volume of insecticide sprays, bollworms population, production cost and environmental contamination. However, reduction in insecticide sprays, especially during flowering and boll formation has led to resurgence of some minor pests such as tobacco caterpillar, mealy bugs, thrips, aphids, leafhoppers, green stink bug, and serpentine leaf miner. The reduced insecticide use and personal experience of farmers of not having negative impact of Bt cotton on the population buildup of bee colonies, has encouraged beekeepers to keep their bee hives in Bt cotton in Haryana, Rajasthan and Punjab in India. From the field scale studies it is also apparent that there are no adverse effects of Bt cotton on the arthropod diversity and natural enemy functions in the cotton ecosystem, and if any are much lower than that of use of insecticides, which have little ecological impact. However, Indian experience with Bt cotton cultivation reveals that the development of resistance in target pests to Bt can t be ignored, and the resistance monitoring andmanagement strategies are essential and need greater attention to sustain Bt technology.