NEWS

Glow-in-the-Dark Sterile Flies Latest Weapon Deployed in U.S. Gauntlet Against Flesh-Eating Parasite

Red River Radio | By Jeff Ferrell,

Published February 16, 2026 at 12:38 PM CST

The USDA estimates an outbreak of New World screwworm (NWS) could cost Texas cattle producers $732 million and deal a $1.8 billion blow to the state economy; 100 million sterile flies are now being released weekly.

The United States is expanding its efforts to combat the spread of the New World screwworm (NWS) from coming into Texas. One technique includes a combination of sterile flies and fluorescent dye. Female screwworm flies mate with sterile male flies resulting in unfertilized eggs that don’t hatch.
As Texas Public Radio reports, veterinarian Dr. Casey Locklear explained the purpose of the dye. “This glow-in-the-dark aspect is a really neat and easy way for scientists to distinguish a safe fly that’s part of our proactive measures versus a potential threatening fly that’s made its way into a new area." Dr. Locklear likened the practice to “insect birth control.”

The USDA advises that vigilance and early detection are critical in defense of New World screwworms, when mitigation efforts have a far more likely chance of success.

While there are no reported cases of screwworm currently in Texas, the flesh-eating parasite could pose a very serious threat to the livestock industry if it were to make its way into Texas. The closest active case of NWS is now around 200 miles from the Texas-Mexico border, according to the United States Department of Agriculture (USDA). When NWS flesh-eating larvae (maggots) burrow into the flesh of a living animal, they cause serious, often deadly damage to the animal. NWS can infest livestock, pets, wildlife, sometimes even birds and in rare cases, people.
Texas Governor Greg Abbott declared a state of emergency on January 29, 2026, to combat the NWS threat. The declaration instructed the Texas Parks and Wildlife Department and the Texas Animal Health Commission to create a joint Texas New World Screwworm Response Team.
Just one week ago, on Monday, February 9, 2026, USDA leaders and Gov. Abbott announced the completion of a U.S.-based sterile fly dispersal facility in Edinburg, Texas, about 20 miles north of the border. The USDA is now releasing roughly 100 million sterile New World screwworm (NWS) flies per week focused along the U.S.-Mexico border, and about 50 miles into Texas.

Any warm-blooded animal is a potential host, but typically involve large hooved livestock including cattle, sheep, and horses. Less common cases reported involve humans, dogs, and wild mammals like rabbits, deer, etc.) and birds.

In June 2025, Agriculture Secretary Brooke Rollins announced his agency's 5-point plan of attack against the slowly-encroaching NWS menace. Part of the plan detailed the success of the 1960s eradication effort which utilized the very same sterile fly dispersal method that pushed the flesh-eating pest back into South America by 1966; that is until their detection in southern Mexico on November 22, 2024. It was that detection which restarted this entire mass eradication process once again.