USDA advances male-only fly tech to boost screwworm eradication
A new USDA genetic breakthrough could double sterile fly output, strengthening defenses against a major livestock pest in North America.
The USDA is advancing a new genetic technology to produce 100% sterile male flies aimed at eradicating the New World screwworm (NWS), a devastating livestock pest, with the goal of doubling production efficiency and strengthening protection for U.S. ranchers, as federal agencies accelerate efforts in 2026 to prevent the pest from spreading northward and disrupting animal agriculture.
Developed by the agency's Agricultural Research Service, the innovation enhances the long-established sterile insect technique (SIT) by eliminating the production of female flies, which do not contribute to pest control efforts. By generating only sterile males, USDA scientists expect to effectively double output without expanding existing infrastructure, a key advantage as pressure grows to contain the pest across the Americas.
According to the APHIS, New World screwworm larvae can cause severe and often fatal damage by burrowing into the flesh of live animals, posing a serious risk to livestock, wildlife and, in rare cases, humans. The pest represents a significant threat to U.S. cattle operations, animal health systems and export markets, making prevention a top priority for federal and state agencies.
According to APHIS, the New World screwworm is a highly destructive pest whose larvae invade the living tissue of animals, causing severe and often fatal damage, and can affect livestock, pets, wildlife, and in rare cases, humans.
Current sterile fly production is centered at an international facility in Panama, but USDA is expanding capacity through multiple initiatives. A $21 million investment in Mexico will help renovate a facility in Metapa, while a new production site at Moore Air Base in Texas is expected to produce up to 300 million sterile flies per week at full capacity, according to federal officials.
The introduction of the genetically engineered "NovoFly" strain marks a critical step forward. Because female screwworm flies mate only once, pairing them with sterile males prevents reproduction entirely, gradually suppressing and ultimately eliminating pest populations when combined with surveillance and movement controls.
Officials say the innovation could significantly improve the efficiency of ongoing eradication campaigns. "We've been losing half of the production because only male flies are effective," explained USDA leadership, noting that the new technology removes that limitation and allows facilities to operate at full biological efficiency.
The regulatory process is now underway, with the Environmental Protection Agency reviewing the genetically engineered strain under existing pesticide and emergency exemption frameworks. A public comment period is open through April 27 as part of the approval pathway, reflecting the urgency of deploying new tools to contain the pest.
At the policy level, the effort aligns with broader USDA priorities to modernize animal health defenses, protect livestock productivity and reduce economic risks across the agricultural supply chain. As global trade and climate pressures increase the movement of pests and diseases, innovations like the male-only sterile fly system are expected to play a growing role in safeguarding U.S. agriculture.
