Screwworm Threat Forces USDA to Act—Ports Closed Again

July 9, 2025

The U.S. Department of Agriculture (USDA) has once again closed southern ports of entry to cattle shipments following the detection of New World screwworm in northern Veracruz, Mexico. The case marks a concerning development, with the pest now appearing roughly 160 miles north of the zone where sterile flies are currently being released. The detection site is located approximately 370 miles south of the U.S.–Mexico border.

This new closure follows a prior USDA decision earlier this year to reopen ports after temporary restrictions. The continued spread of screwworm has prompted renewed action to protect the U.S. cattle herd.

Secretary of Agriculture Brooke Rollins is basing her decisions on real-time assessments from USDA veterinary staff in Mexico. She has been actively working to manage the risk while also considering the economic impact on American cattle producers.

The National Cattlemen’s Beef Association (NCBA) responded to the development, emphasizing the urgency of the situation. “The northward movement of screwworm jeopardizes American agriculture,” said NCBA CEO Colin Woodall. “Secretary Rollins has made the difficult but necessary call to pause cattle movements again until progress is made in pushing the screwworm further from our border.”

Woodall praised the Secretary’s efforts in pressuring Mexico to act more decisively, noting that she removed bureaucratic delays that had hindered sterile fly releases and increased surveillance. However, he stressed that more must be done.

“It’s clear the U.S. needs its own sterile fly production facility,” he added. “We can’t keep relying solely on Mexico. We urge USDA to immediately begin building that capability here at home.”

Earlier this year, USDA designated Moore Air Base in South Texas as the future site for a sterile fly dispersal facility. NCBA is now urging USDA to fast-track the development of a fly production facility to ensure sufficient coverage to protect the U.S. cattle industry.

NCBA said it will continue to monitor developments, work closely with USDA, and coordinate with stakeholders as the situation unfolds.