The U.S. Department of Agriculture is deploying an unlikely weapon against a resurgent threat: sterile flies. On June 27, the agency inaugurated a 22,000-square-foot production plant in Metapa, Mexico, to breed and release them in response to rising cases of the New World screwworm, a flesh-eating parasitic fly lethal to animals.
According to the USDA, the facility has been under construction for the past 11 months, a joint effort between the current administration and the Mexican government. The plant is set to produce up to 180 million sterile flies for release. The strategy relies on the sterile insect technique, where sterilized males mate with wild females, producing no offspring and gradually collapsing the pest population.
The inauguration comes as the parasite, believed eradicated in the U.S. since the 1960s, makes a troubling comeback. At least 27 new animal cases have been reported across two states since June 3, 2026, according to the USDA. Texas is currently the only state with active cases, and authorities have quarantined parts of 20 counties. All infected animals have been domestic; no cases have been detected in wildlife so far.
The outbreak signals a potential breakdown in biosecurity measures that had kept the screwworm at bay for decades. The rapid jump from zero to 27 cases in under a month raises questions about surveillance gaps and cross-border livestock movement. The sterile fly approach, while proven effective against similar pests, requires sustained large-scale releases and faces logistical hurdles in remote areas.
However, the strategy is not without critics. Some entomologists caution that sterile insect programs are slow to take effect and highly dependent on perfect timing and environmental conditions. If the outbreak spreads faster than flies can be sterilized and released, the containment window may close. Others question whether the facility's output will be sufficient if cases continue to climb beyond Texas borders.