The U.S. government is preparing a massive campaign against the “screwworm fly,” a tropical grub that can kill cattle and domestic animals within days. The fly, in fact, lays eggs in the wounds of warm-blooded animals, including humans.
Billions of sterile male flies will be bred and dropped from planes over Mexico and Texas to collapse the pest’s population. Sterile flies mate with fertile wild females, but because they are sterile, these unions do not produce fertile eggs. Since females mate only once in their lives, mating with sterile males prevents them from reproducing further.
Over time, this strategy dramatically reduces the population of parasitic flies until they disappear, without resorting to chemical pesticides or harming the environment.
The United States is opening new sterile fly breeding and distribution facilities in southern Texas and southern Mexico, with the goal of achieving a production of 400 million flies per week. Release is from light aircraft, and security is critical to prevent the escape of fertile flies or other incidents.
The program, used successfully in the past, is considered one of the best examples of science applied to agriculture. However, there is no shortage of risks: an aerial mission has already cost the lives of three people when, on June 6, 2025, in the Mexican state of Chiapas, near the border with Guatemala, a plane engaged in a pest control operation crashed, killing two Guatemalan pilots and a Mexican agricultural engineer. Mexican authorities have not yet determined the cause of the crash.
In the meantime, authorities fear that the fly menace may return to affect humans as well.
The method is considered effective and more environmentally friendly than using pesticides. Experts stress that even after the pest is eradicated, vigilance must be maintained to prevent new reappearances.
