The U.S. Department of Agriculture has confirmed that the New World screwworm fly has arrived in south Texas, and Texas officials have moved to contain it with a 12-mile quarantine zone. The response is aimed at keeping animals from leaving the area without inspection as the pest reappears in the state for the first time since 1966.
Brooke Rollins, the agriculture secretary, is confronting a problem that ranchers thought had been beaten back generations ago. The fly is threatening the $113 billion U.S. cattle industry, with Texas alone home to $17 billion worth of cattle, and the latest federal update on Monday added two new cases to the tally.
One of those cases was found in a dog in Lea County, New Mexico, just across the state line. The other was identified in a calf in La Salle County, Texas, hundreds of miles away, bringing the total reported cases to four. That spread matters because it suggests the parasite is not confined to a single point, even though officials have not said how far beyond those cases it may have moved.
The screwworm was once an annual warm-weather scourge for cattle ranchers from the 1930s through the 1960s. The United States eventually wiped it out by breeding sterile male flies and dropping them from planes to mate with wild females, a campaign that kept the pest out of the country for decades. Deadly flies were detected in Mexico late in 2024 after years of being contained at the southern end of Panama, setting the stage for the return now being seen in Texas.
Texas response activity was underway at the State Operations Center in Austin on Friday, June 5, 2026, as officials pressed ahead with eradication efforts. Animals leaving the quarantine zone will need inspection, and the state’s next task is simple to say and hard to carry out: stop the infestation from gaining a foothold in the top cattle state in the country.
