Agriculture Secretary Brooke Rollins on July 29 announced a $25 million commitment for a sterile fly dispersal facility in Arizona to strengthen the long-term U.S. response to the New World Screwworm, visiting the Douglas Port of Entry as part of the announcement.
The facility will produce and release sterile screwworm flies, a proven biological control method that suppresses wild populations by preventing successful reproduction. The technique, known as the sterile insect technique, was used to eradicate the screwworm from the United States in the 1960s.
The New World Screwworm is a parasitic fly that kills livestock by laying eggs in open wounds, where larvae burrow into living flesh. It is considered the most economically devastating livestock pest in history and poses a recurring reinfestation threat from Mexico.
The Arizona site will serve as a first line of defense for cattle entering through southern ports of entry, which are being phased back open beginning Aug. 24. The southern ports were closed as a biosecurity measure during a screwworm alert earlier in 2026.
The investment directly supports the reopening of southern cattle trade routes, which are vital to the U.S. beef industry. Ranchers along the border have been unable to import Mexican feeder cattle while the ports remained closed.
The sterile insect technique works by flooding an area with sterile male flies that mate with wild females but produce no offspring, gradually collapsing the wild population. The method requires sustained production and release of large numbers of sterile flies to maintain effectiveness.