Releasing sterile moths into cotton fields keeps levels of the dreaded pink bollworm moth (Pectinophora gossypiella) to a minimum — a strategy that could prevent the pest from becoming resistant to insecticide-producing crops.
Pink bollworms gradually evolve resistance to the Cry1Ac toxin made by genetically modified cotton, especially if farmers fail to maintain nearby refuges of non-toxic crops.
Computer simulations developed by Bruce Tabashnik at the University of Arizona in Tucson and his colleagues suggested that releasing sterile bollworm moths would decrease the bollworm population and lessen the chance that two Cry1Ac-resistant moths would mate and propagate the trait. The model predicted that after more than 20 years, Cry1Ac resistance would not emerge, even in the absence of refuges.
A four-year field experiment on modified and conventional cotton across the state of Arizona backed up the computer model: between 2006 and 2009, pink bollworm infestation rates plummeted by 99.9%.
For a longer story on this research, see http://go.nature.com/gsurwm