Texas Gov. Greg Abbott expressed concern Friday that a new factory isn't expected to start breeding sterile New World screwworm flies for more than a year as a big part of the effort to stop its flesh-eating larvae from threatening the $113 U.S. billion cattle industry.
Abbott pledged Texas will help the U.S. Department of Agriculture accelerate construction of the $750 million breeding facility outside Edinburg, Texas, about 20 miles (32 kilometers) north of the U.S.-Mexico border. He said Texas is willing to spend its own funds to see that construction is “24 hours a day, seven days a week.”
Without greater sterile fly production, Abbott said during a news conference in the state capital of Austin, “We cannot make it through a second summer.”
The USDA confirmed an infestation of New World screwworm fly larvae this week in a 3-week-old calf in La Pryor, Texas, about 100 miles (161 kilometers) southwest of San Antonio and 50 miles (80 kilometers) from the Mexico border. It's the first case confirmed in Texas since 1966.
The new factory in Texas is the larger of two fly-breeding facilities funded by the USDA.
Separately, the USDA invested $21 million in converting a site in southern Mexico from breeding fruit flies to breeding screwworm flies. That factory is expected to start producing flies next month, eventually 100 million a week.
The other factory in Texas will be the size of two Costco stores, said Rear Admiral Michael Schmoyer, a member of the USDA's screwworm response team. It is expected to produce up to 300 million flies a week.
Officials believe both factories are needed to eradicate the fly from the U.S., Mexico and Central America.
Schmoyer said the federal government has already shortened the planning and construction timeline considerably — drafting plans in a few months rather than taking a year, for example. U.S. Agriculture Secretary Brooke Rollins said the USDA hopes it will be running sooner than its planned November 2027 opening date.
But Abbott said Texas is determined to have construction go even faster.
“This is going to spread over the course of the summer,” he said of the fly.
Infestation hits among record beef prices
An untreated infestation of New World screwworm fly larvae can kill an animal, but there are now a dozen government-approved medications to treat livestock. Federal and state officials have been quick to stress that fly's larvae — which feed on living material — do not infest meat or fruit.
“There’s a food production issue, but not a food safety issue,” Abbott said.
Derrell Peel, a professor of agribusiness at Oklahoma State University, said the beef supply isn't likely to be affected unless officials restrict cattle movement more than locally or unless infestations appear in feedlots or other places where cattle are concentrated. He does not expect that to happen.
“It's probably not a major market issue,” he said.
Consumers are paying record beef prices because of a tight cattle supply, and Peel expects prices to rise even further when ranchers take heifers out of the supply chain to rebuild their herds. But he said the arrival of the screwworm in Texas “doesn't change the supply fundamentals.”
Screwworm outbreaks in Mexico starting in 2024 prompted U.S. Agriculture Secretary Brooke Rollins to close U.S. ports of entry to its cattle in May 2025. Mexican imports were once about 1.2 million animals a year and dropped about 80% last year, according to industry statistics.
But Peel said Mexican imports were only about 3% of the U.S. cattle supply.
“It's been just one more thing on top of others,” he said, not a major driver of prices.
Breeding sterile flies has eradicated pest before
The New World screwworm fly was an annual, warm-weather scourge of U.S. cattle ranchers from at least the 1930s through the 1960s.
But breeding sterile flies and dropping swarms of them from planes eradicated it from the U.S. by the early 1970s, except for a brief outbreak among deer in the Florida Keys in 2016 and a case confirmed in a Maryland man who traveled to El Salvador last year. Until an outbreak in Panama in 2023, the fly had been considered eradicated outside its remote, southernmost region bordering Colombia.
Females mate once in their monthslong lives, and if they breed with sterile male flies, their eggs won’t hatch after being laid in open wounds and mucous membranes of warm-blooded animals, including cattle, wild mammals, household pets and humans.
Once the U.S. and other nations eradicated the fly years ago, they shut down fly-breeding facilities until there was only one left in the Western Hemisphere, in Panama. It can produce about 117 million flies a week.
However, past eradication efforts needed about 500 million flies a week, said Schmoyer, a member of the USDA’s screwworm response team, during Abbott's news conference.
With fly drops, officials try to predict future
Schmoyer estimated that the USDA already has dispersed 130 million flies in Texas since January, most of them from planes, and those drops are now about 4 million a week. It also is releasing another 4 million a week in the ground as pupae, which are flies in the stage between larvae and adult.
But, even with those millions of flies, the USDA must be strategic about where to disperse them, Schmoyer told reporters. Federal and state officials are using scientific models to predict how the fly will move.
“In essence, it’s not where the flies are today, but where they could be weeks from now,” he said.
Part of the science involves traps, and Texas State Veterinarian Bud Dinges said they've been deployed up to 120 miles (193 kilometers) away from La Pryor to monitor the fly's movement.
