With confirmed detections of New World screwworm in Texas and New Mexico, the pest has returned. Largely due to the Biden administration’s open border policy and lack of attention to the potential issue, the screwworm threat has reached American soil.
For months, we watched screwworm steadily advance through Mexico. During that time, I repeatedly warned that we could not afford to rely solely on existing sterile fly production while waiting years for new production facilities to come online. I called for stronger border protections, expanded surveillance, increased sterile fly production, and immediate deployment of every proven tool available.
IN FOCUS: HOW SCREWWORM OUTBREAK BECAME A PARTISAN BLAME GAME
Because of those concerns, I personally placed Department of Agriculture research on the Screwworm Adult Suppression System and the original bait formula into the USDA’s hands on three separate occasions. I knew time was running short. Unfortunately, that warning has now become reality.
The solution already exists. Developed and tested by USDA scientists, SWASS is a toxic bait system that combines a powerful attractant, bait, and insecticide to rapidly reduce adult screwworm populations. It works by attracting and killing adult screwworm flies before they can reproduce and spread.
Field trials delivered extraordinary results. On Curacao Island, adult screwworm populations dropped by as much as 85% in just 15 weeks, allowing sterile fly releases to complete eradication shortly thereafter. Additional trials in Texas, Arizona, New Mexico, and Mexico routinely reduced screwworm populations by more than 70% with only a few applications.
By the early 1980s, SWASS had become a key component of the campaign that eradicated screwworm from the United States, Mexico, Central America, and parts of the Caribbean.
Today, the formula is well documented and can be modernized with Environmental Protection Agency-approved insecticides and improved attractants. The Texas Department of Agriculture is currently working with an entity that has identified reformulated SWASS using modern EPA-approved insecticides, and we stand ready to provide USDA with that formulation as soon as it becomes available. Production could begin in weeks, not years.
Most importantly, SWASS would help bridge the dangerous gap between today’s limited sterile fly production capacity and the day new facilities become fully operational.
I strongly support the new sterile fly production facility being built in South Texas, and I commend President Donald Trump, Agriculture Secretary Brooke Rollins, and everyone involved in making that project a reality. Expanding sterile fly production is essential to long-term success.
But we cannot afford to rely exclusively on sterile fly releases when another proven tool is sitting on the shelf.
This is not an either-or choice. The most successful screwworm eradication campaigns have always relied on multiple tools working together. SWASS complements sterile fly releases by rapidly suppressing adult fly populations and buying valuable time. That is why every proven tool should be deployed simultaneously.
Over the past several months, I have worked with ranchers, veterinarians, legislative leaders, USDA officials, and the Trump administration to keep attention focused on this threat. I have pushed for expanded sterile fly capacity, supported the South Texas facility, and consistently urged immediate consideration of SWASS deployment.
My message has never changed: hope is not a strategy. Proven tools are.
The economic stakes could not be higher. The last major screwworm outbreaks cost American livestock producers hundreds of millions of dollars annually. Today, the damage would be far greater. Texas alone is home to more than 12 million head of cattle. An established screwworm population would threaten livestock production, wildlife populations, pets, hunting operations, and international trade.
A SWASS deployment program would cost millions. A major screwworm outbreak would cost billions. That is a simple calculation.
I encourage the USDA to immediately authorize and fund a comprehensive SWASS deployment program along the U.S.-Mexico border and throughout high-risk areas of the Southwest. Federal officials should work closely with Mexico to coordinate deployment, scale up bait production, intensify surveillance efforts, and continue expanding sterile fly production capacity.
America defeated screwworm before because we used every effective tool available.
OPINION: AMERICA SAW THE SCREWWORM COMING. WHY WEREN’T WE PREPARED?
Today, one of those proven tools is sitting on the shelf while screwworm has once again reached American soil.
We have the tools. We know they work. The only question is whether we will use them before biology outruns bureaucracy.
Sid Miller is the Texas agriculture commissioner.