Insecticide Management in Cotton: Progress and Prospects

摘要

Chemical insecticides continue to be a necessary input for profitable cotton production. Recently, cotton's share of the global insecticide market declined from 24% in 1994 to 14.8% in 2010. Such a decline did correspond with the increased adoption oftransgenic cotton during that period. Prior to the introduction of Bt cotton in 1996, bollworms had accounted for at least 50% of all chemical insecticides used on the crop annually. Bt cotton is toxic to bollworms and generally does not warrant any supplemental need for insecticide use, except when bollworms develop resistance to Bt cotton. Estimates show that extensive cultivation of Bt cotton resulted in the reduction of insecticide usage by 268.6 million kilograms (kg) from 1996 to 2015 (Brookes and Barfoot, 2017}. However, the recent increasing trends in the use of insecticides have been necessitated by the need to suppress a global resurgence of sucking pests, as well as the pink bollworm, which has recently developed resistance to Bt cotton inChina, India and Pakistan. On conventional cotton, the rise in insecticide use has been in response to the growing need to deal with the increased spread of some major cotton pests across continents, and the advent of insecticide resistance. In low-income countries, increased use of insecticides is also being fuelled by increased informal trade in pesticides due to rampant market failures. In this paper, I discuss these developments together with some of the steps that are needed for more sustainable insecticide use in cotton.