USDA Marks Billionth Sterile Fly Release as Screwworm Cases Remain Low

Key points

• The USDA released its billionth sterile fly in Texas as part of the sterile insect technique to fight the New World screwworm.
• The New World screwworm lays eggs on warm-blooded animals, leading to dangerous infections.
• The pest was previously eradicated in the U.S. decades ago through the release of sterile flies.
• In June, the USDA reported its first U.S. cases of the screwworm in years.
• Fewer than 50 screwworm cases have been recorded in the U.S. this year.
• The Trump administration is working to ramp up sterile fly production to meet demand.

Background

The New World screwworm was eradicated in the U.S. decades ago using the sterile insect technique. Recent cases in the U.S. have prompted a renewed effort to combat the pest. In July 2026, the Arizona-Sonora border reopened to cattle after a yearlong closure to combat the screwworm. The USDA deemed Sonora and Chihuahua low risk, and Arizona intensified screening with electronic IDs instead of ear tags to reduce trauma and infestation risk. The effort includes a joint sterile-fly program in southern Mexico, as Texas cases of the parasite threaten U.S. cattle herds and beef prices.

How outlets are covering it

CNN and KY3 report on the USDA's release of its billionth sterile fly in Texas to combat the New World screwworm, noting that fewer than 50 cases have been recorded in the U.S. this year. CNN highlights the Trump administration's efforts to ramp up sterile fly production, while KY3 emphasizes the milestone of the billionth fly release. Yahoo reports on Texas releasing 700 million sterile flies that glow under UV to stop the flesh-eating screwworm, providing a different perspective on the scale of the operation. Meatingplace reports on the USDA setting dates for New World Screwworm Response Playbook Reviews, indicating a broader regulatory response to the pest. The sources generally agree on the USDA's efforts to combat the screwworm, but differ in their emphasis on the scale of the operation and the regulatory response.

Why it matters

The New World screwworm poses a significant threat to livestock and the agricultural industry. The USDA's release of its billionth sterile fly marks a significant milestone in the fight against the pest, demonstrating the scale of the federal response. The sterile insect technique is a critical tool in the eradication of the screwworm, and the recent cases in the U.S. have prompted a renewed effort to combat the pest. The success of the campaign will depend on the ability to produce and release sufficient sterile flies to interrupt the pest's breeding cycle.

What to watch

The USDA will continue to ramp up sterile fly production to meet demand. The Trump administration is working to ensure sufficient supply for the ongoing campaign. Scientists will continue to monitor the situation and assess the effectiveness of the sterile insect technique. The USDA will also continue to review and update its New World Screwworm Response Playbook to ensure a comprehensive and effective response to the pest.