What To Know About The New World Screwworm Fly

The New World screwworm fly is threatening the $113 billion U.S. cattle industry for the first time in more than a half century. An infestation from its flesh-eating larvae has been confirmed in south Texas in a 3-week-old calf in La Pryor, about 100 miles southwest of San Antonio. Federal and state officials had been working to keep the parasite from reaching Texas since its late 2024 appearance in southern Mexico. Before that, it had been contained in Panama for years. The U.S. eradicated the pest by the early 1970s by breeding sterile male flies and dropping swarms from planes to mate with wild females. Millions are being released each week now.