The Fall and Rise of Screwworm
The article traces the history of the screwworm, a devastating livestock pest in the Southern US, and the development of the Sterile Insect Technique (SIT) to eradicate it in the mid-20th century. It then describes the recent resurgence of the New World screwworm in the Florida Keys due to warming climates, threatening livestock and wildlife, and the renewed use of SIT to combat the outbreak.
Background
Screwworms are the parasitic larvae (maggots) of the New World screwworm fly (*Cochliomyia hominivorax*). Unlike typical maggots that feed on dead tissue, screwworm larvae burrow into the living flesh of warm-blooded animals — including livestock, pets, and occasionally humans — causing severe wounds and often death if untreated. A massive mid-20th-century eradication program using the Sterile Insect Technique (releasing radiation-sterilized male flies to mate with wild females, producing no offspring) successfully wiped out screwworms from the US and much of Central America. That program was a landmark of applied entomology and public-private agricultural cooperation. But in recent years, screwworms have re-emerged in Florida and other regions, threatening livestock industries again. The article traces the history of the original eradication campaign and explains what changed to allow the pest's return.