Screwworm

In the early 1970s, USDA's progress in eradicating screwworm—among the deadliest and most vicious of livestock pests—was at a crossroads. Department scientists had revolutionized the country's battle against the insect by creating a new technology. The concept was simple yet profound: rear and aerially distribute masses of sterile screwworm flies in infested areas, so the resident fly populations would have increasing difficulty reproducing—and eventually breed themselves out of existence. The new approach worked so well that by 1966, USDA declared screwworm eradicated within U.S. borders.

Eliminating screwworms from the United States saves farmers and ranchers nearly $900 million in lost livestock each year.

Early in October 2016, the U.S. Department of Agriculture (USDA) was faced once again with New World screwworm, which had been eradicated from the United States more than three decades ago. Infestation of this flesh-eating parasite was confirmed in deer from the National Key Deer Refuge in the Florida Keys.

USDA’s Animal and Plant Health Inspection Service (APHIS) immediately began releasing sterile male flies in Florida’s affected areas as part of an aggressive eradication campaign. By March 2017, the screwworm had been successfully eradicated from Florida.

An interactive story map of the USDA's history of eradicating the infestation and the continuing efforts to keep screwworm out of the U.S.
See also: APHIS Interactive Maps to explore plant and animal health or wildlife damage management data and an index of APHIS Maps