US Plans Massive Fly Drop to Stop Flesh-Eating Threat

The USDA will release millions of sterilized male screwworm flies near the U.S.-Mexico border using a new dispersal facility at Moore Air Base, Texas, to prevent the spread of the New World screwworm, a parasite posing a serious threat to livestock and wildlife. The United States Department of Agriculture is launching a large-scale operation to suppress the spread of New World screwworms, a deadly pest threatening to cross into Texas and beyond.

The New World screwworm, the larval stage of the blow fly species Cochliomyia hominivorax, is unlike other insects because it attacks living animals rather than decomposing flesh. After a female fly lays hundreds of eggs in wounds or soft tissue, the larvae hatch within a day and burrow into the host, consuming flesh and creating gaping wounds. If left untreated, an infestation can kill cattle or wildlife in a matter of weeks. Since late 2024, screwworm outbreaks have intensified throughout Central America and have now reached northern Mexican states like Veracruz, about 370 miles from Texas, prompting the USDA to suspend livestock imports and accelerate preventive measures.

While this strategy may sound unorthodox, the method has been proven effective before. In the 1960s and 1970s, federal agencies eradicated screwworms in the United States by releasing vast numbers of sterilized male flies that mated with wild females, rendering their eggs infertile. According to the United States Department of Agriculture, this “sterile insect technique” gradually collapses parasite populations without chemicals or pesticides.

However, producing enough sterile flies to counter the current outbreak is a massive undertaking. At present, only one facility operated by the Panama-United States Commission for the Eradication and Prevention of Screwworm Infestation in Livestock, known as COPEG, produces sterilized screwworms. In response to the outbreak, lawmakers urged the USDA to expand capacity. The USDA announced an $8.5 million sterile fly dispersal facility at Moore Air Base in Edinburg, Texas; it is also considering a larger production facility at the same site, which could cost between $300-600 million and be operational in 2-3 years.

Ranchers are already bracing for impact. Stephen Diebel, first vice president of the Texas & Southwestern Cattle Raisers Association, underscored the threat in plain terms: “It’s a daily chore to provide those inspections to our livestock, just to make sure they’re not infested,” he told the media. “We know the incredible economic impact an infestation would cause.” There are currently no approved vaccines or proven repellents to protect herds, leaving prevention and monitoring as the only viable safeguards.

Though costly, sterile-fly release remains the most effective and time-tested strategy. Without intervention, screwworm infestation could cost the U.S. cattle industry over $100 billion. Industry leaders and USDA officials emphasize the strategy’s necessity to protect livestock, wildlife, and food security.