The program began in 1996, after concerns over the use of the pesticide malathion, which was used to control the invasive flies. Having been found in Hawaii in

The program began in 1996, after concerns over the use of the pesticide malathion, which was used to control the invasive flies. Having been found in Hawaii in 1910, the flies had made their way to California by 1975. In response, officials dropped 2.5 million sterile male Mediterranean fruit flies in western Los Angeles County. But in 1981, the U.S.D.A. accidentally released hundreds of thousands of fertile males, posing a threat to California’s agriculture industry, and reviving support for the pesticide. For years, the department used both approaches, but ultimately ceased the use of the pesticide.