Threat Looms as Screwworm Nears US

REDFIELD, Iowa (DTN) -- New World screwworm (NWS) continues to move closer to the United States with a confirmed case less than 70 miles from the border in Sabinas Hidalgo, Nuevo Leon, Mexico.

Mexico's National Service of Agro-Alimentary Health, Safety, and Quality (SENASICA) confirmed this case on Sept. 21. A USDA news release said this case is one of the most threatening to the American cattle and livestock industry due to the location near the high-traffic major highway from Monterrey, Nuevo Leon, to Laredo, Texas.

U.S. Secretary of Agriculture Brooke Rollins said the protection of the U.S. from NWS is a national security priority. "We have given Mexico every opportunity and every resource necessary to counter NWS since announcing the NWS Bold Plan in June 2025," Rollins said in the release. "We are firmly executing our five-pronged plan and will take decisive action to protect our borders, even in the absence of cooperation."

On July 9, 2025, NWS was detected about 370 miles from the border in Veracruz. The SENASICA reports indicate the affected animal had recently been moved to a certified feedlot in Nuevo Leon from a region in southern Mexico with active NWS cases. The U.S. ports remain closed to imports of cattle, bison and horses from Mexico and have been since the July 9 case.

MONITORING CONTINUES AT BORDER

Since then, USDA and Mexico have been monitoring almost 8,000 traps across Texas, Arizona, and New Mexico. Currently, all the 13,000-plus screening samples have detected no NWS flies.

R-CALF USA CEO Bill Bullard commended Rollins' continued actions to keep NWS out of the U.S. He said, in a statement, "The NWS presents a serious threat to U.S. livestock, and both our nation's cattle and sheep herds have already declined to historically low levels, as have the number of U.S. cattle and sheep farms and ranches. We must, as the Secretary is doing, take every precaution to prevent this pest's introduction into the United States."

The National Cattlemen's Beef Association (NCBA) is also concerned with the speed of northward movement of NWS in Mexico. NCBA CEO Colin Woodall said in a statement, "With the threat so close, we need more sterile fly dispersal to push this pest back from our border. Now is the time for USDA to expedite construction of the domestic sterile fly facility and eradicate this pest from our doorstep."

Bullard and Woodall stressed the importance of stopping the pest and suggested Rollins persuade Mexico to halt northward movement of livestock within that country and hold Mexico accountable for this movement.

Bullard also suggested halting any unlawful trafficking of cattle from South America to Mexico, until the NWS is eradicated within Mexico. Woodall said NCBA urges the Environmental Protection Agency to authorize new pesticide products to combat screwworm and provide another tool for American cattle producers.

Additionally, USDA is expected to release a significant plan soon to help rebuild the U.S. cattle supply with an incentive for ranchers to drive a revitalization of the American beef industry. This has support from R-CALF USA as it states this is an important goal to meet.

Also see: "USDA Invests $850M in NWS Fight," https://www.dtnpf.com/….

Jennifer Carrico can be reached at jennifer.carrico@dtn.com

Follow her on social platform X @JennCattleGal

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