Rollins presses Mexico to stop spread of New World screwworm

The nation’s ag secretary sent a letter to her counterpart in Mexico demanding it eliminate restrictions on U.S. Department of Agriculture aircraft and waive customs duties on eradication equipment that are impairing her country’s response to stop the spread of the New World screwworm.

Secretary Brooke Rollins wrote, “Every delay in granting full operational authority and eliminating customs barriers undermines our collective ability to carry out this emergency response.”

Additionally, Rollins informed the government of Mexico, “…that if these issues are not resolved by Wednesday, April 30, USDA will restrict the importation of animal commodities, which consist of live cattle, bison and equine originating from or transiting Mexico to protect the interest of the agriculture industry in the United States.”

The USDA continues to take all necessary action to stop the spread of New World screwworm in southern Mexico to protect America’s livestock industry, food supply and wildlife populations before it reaches the U.S. border, she said. New World screwworm is a deadly parasitic fly that infests warm-blooded animals, causing severe wounds and complications that can lead to death. A NWS infestation in the U.S. will result in significant losses to livestock industries.

The U.S. successfully led the eradication of NWS in the U.S. and Mexico, but recent detections in Mexico show that this dangerous pest is back and remains a serious threat. Ongoing vigilance and control efforts are critical to prevent its spread northward and protect animal health and agriculture.

The National Cattlemen’s Beef Association said Rollins’ actions were appropriate and two spokesmen supported it.

“The U.S. spent millions of dollars to eradicate New World screwworm from our borders in the 1960s, but unfortunately, we are now facing this dangerous threat again,” said NCBA president and Nebraska cattleman Buck Wehrbein. “Screwworm is very destructive and could cost American producers millions of dollars a year if it reaches us. Americans have been investing in prevention efforts in Central America for decades, but we can’t stop this without Mexico’s participation. NCBA strongly supports Secretary Rollins holding Mexico to their commitments regarding screwworm eradication.” 

In November 2024, USDA was notified that New World screwworm was detected in Mexico. NCBA has been working closely with USDA’s Animal and Plant Health Inspection Service to increase surveillance, inspection, and other measures to counter this pest. 

At the same time, NCBA has also been working with USDA to expand the use of the sterile insect technique, which requires the continuous release of sterile male screwworm files that breed with wild screwworms and result in no offspring, eradicating the species. 

Unfortunately, Mexican authorities have failed to uphold their end of the agreement by disrupting planes carrying these sterile male files, refusing pilots permission to land, and instituting customs duties on flight components, sterile flies, and sterile insect technique equipment. 

“We have received multiple reports that critical flights carrying these sterile flies have been denied permission to land, faced bogus paperwork issues, and been charged high customs fees. As a result, we have lost significant time and investment that has allowed these dangerous pests to spread unchecked into southern Mexico,” said NCBA Senior Vice President of Government Affairs Ethan Lane. “In light of those reports, NCBA met with the Mexican Embassy earlier this week to deliver the message that the Mexican government needs to be a partner on eradicating screwworms to protect both animal and human health. It’s time for Mexican authorities to act and we appreciate Secretary Rollins standing with American and Mexican cattle producers who want to see this pest stopped dead in its tracks.” 

Her actions were also applauded by the Fort Worth-based Texas & Southwestern Cattle Raisers Association.

“As our neighbor, Mexico has fallen short in its role as a partner in managing the spread of NWS, placing the burden and risk disproportionately on the U.S.,” said Texas & Southwestern Cattle Raisers Association President Carl Ray Polk Jr. “We continually advocate for proactive efforts to manage NWS before it reaches the U.S. border, and welcome the supportive consequences put in place by Secretary Rollins that can spur needed action to protect America’s cattle industry, food supply and wildlife populations.”

Earlier in April, Texas & Southwestern Cattle Raisers Association had boots on the ground in Panama at the world’s only large-scale sterile fly production facility. This facility provides the sole defense against the spread of NWS across North and South America. Flies that came from this facility have inconsistently been denied access in certain parts of Mexico for dispersal flights.

In a letter to her counterpart, Mexico Secretary of Agriculture Julio Antonio Berdeque Sacristan, Rollins said the outbreak in southern Mexico continues to expand, and every day that passes without full deployment of sterile insect technique operations represents a lost opportunity to contain this pest and prevent its spread beyond the Isthmus of Tehuantepec.

The emergency response effort relies on the availability and continuous operation of appropriate aircraft fleets. These aircraft-operated by USDA APHIS-contracted carriers, including Dynamic Aviation—are uniquely equipped to conduct the high-volume, precision aerial releases required to suppress and eliminate the NWS population.

Dave Bergmeier can be reached at 620-227-1822 or [email protected].