Sterile Fly Wall Races North

Mexico and the United States are racing to build a sterile fly wall before New World screwworm spreads farther north.

Quick Take

USDA says the sterile insect method helped wipe out screwworm in the United States in 1966.^[7]
A new sterile fly plant is being built at Moore Air Base in Edinburg, Texas, while Mexico is reopening a plant in Chiapas.^[1]^[2]
Officials say the Texas facility will help the United States stop depending on foreign fly production.^[1]
Texas Agriculture Commissioner Sid Miller says the federal response is too slow and too weak.^[11]^[13]

Why the New Plant Matters

The USDA says the Texas facility will produce sterile flies on American soil and strengthen the border response.^[1]^[2] The agency also says Mexico is modifying its Metapa plant to restart output and speed up releases over infested areas.^[2] Together, those plants are meant to restore a fly barrier that once protected ranchers, livestock, and pets from a pest that burrows into living flesh.^[7]

That old system is not a theory. USDA says sterile insect technique eradicated New World screwworm from the United States in 1966, and federal records show the method also supported later eradication work across Mexico and Central America.^[7]^[22]^[23] The basic biology is simple. Sterile males mate with wild females, the eggs do not hatch, and the population collapses over time.^[5]^[7] That history is why federal officials are betting so heavily on new production plants now.

What USDA Says It Is Doing Now

USDA says the new Texas plant at Moore Air Base will give the United States a domestic production and dispersal site for sterile flies.^[2] The department also says it is renovating the Mexican plant with a $21 million investment to add more weekly output.^[1]^[2] On the public response side, USDA says it has built a broader plan that includes surveillance, animal movement controls, public outreach, sterile insect work, and new tools.^[3]^[6]

The agency says the outbreak response is already large. USDA has said staffing on the screwworm issue grew from 10 employees in January 2024 to 110 by June 2025.^[6] It has also said it is using traps, testing, predictive analytics, and drone support to track the pest.^[6] Federal officials frame the effort as a whole-of-government push because the pest threatens cattle, wildlife, pets, and in rare cases people.^[6]^[7]

Why Critics Say the Response Is Too Weak

Texas Agriculture Commissioner Sid Miller argues that the current sterile fly strategy is not enough. He says half the released flies are female, which weakens the method because only sterile males help suppress the wild population.^[11]^[13] Miller also says farmers may underreport cases because they fear quarantines and more government control.^[11]^[13] That claim matters because weak reporting can hide the true size of the outbreak.

Miller’s other complaint is speed. He says USDA should use the Screwworm Adult Suppression System bait now instead of waiting on fly production.^[11]^[13] He argues the bait can kill most adult flies and says the federal government is moving too slowly while the pest spreads.^[11]^[13] USDA has not accepted that argument, and Secretary Brooke Rollins has publicly dismissed Miller’s criticism as “unserious” and “dangerous,” which only deepens the fight over who is handling the outbreak best.^[6]^[11]

🤝 Defeating New World screwworm requires strong partnerships.

Today, @SecRollins joined President @Claudiashein, @USAmbMex, and our partners in Mexico to celebrate the opening of the new sterile fly production facility. They also discussed rapidly integrating the NOVO fly into… pic.twitter.com/wJTJIZQ8Q6

— New World Screwworm Rapid Response (@Screwworm_RR) June 27, 2026

The stakes are not small. USDA says New World screwworm can damage livestock, pets, wildlife, and even people in rare cases.^[7] Historical records show the pest once cost the industry heavily and required massive fly production campaigns to push it south.^[19]^[22]^[23] For ranchers, that means the debate is not abstract. It is about whether Washington is acting fast enough to protect herds, food supplies, and private property from another expensive federal failure.

What Happens Next

The new plants may help, but the timeline still matters. Reuters reported that Mexico’s plant is expected to reach about 100 million flies a week, while USDA’s Texas site is meant to add more production on U.S. soil.^[1]^[2] That gives officials more capacity, but it does not settle the fight over whether sterile flies alone can stop the outbreak fast enough. For now, the response depends on fast construction, steady releases, and tighter border control.

That leaves a simple question in front of federal officials: will more sterile flies and better surveillance contain the pest, or will delays keep giving screwworm room to spread? USDA says the old method still works.^[7]^[22]^[23] Critics say the current rollout is too slow and too narrow.^[11]^[13] Until the outbreak is contained, ranchers will keep watching the border, the labs, and the paperwork for proof that the government is finally moving at emergency speed.