The U.S. Southeast screwworm eradication campaign was a large-scale test of whether a pest could be eliminated by releasing artificially reared, sterilized males rather than by spreading poison. Over 17 months, the program released 3.5 billion flies across Florida and parts of Georgia and Alabama; after the last known wound infestation in February 1959 and a few subsequent captures in traps, no further trace was found. Its success stood as a vivid contrast to the chemical eradication programs elsewhere in the book: here, basic biological research, persistence, and an enormous coordinated release achieved eradication, though the victory required a quarantine barrier against return from the Southwest.

From the Curaçao trial to a regional campaign

The immediate precedent was the successful experiment on Curaçao, where the screwworm had been eradicated after the release of sterile flies. That result encouraged Florida livestock raisers to seek a similar solution to the costly pest. The Southeast undertaking, however, was about 300 times larger than the Caribbean island trial, making the transition from experiment to regional campaign a substantial leap in scale.

In 1957, the United States Department of Agriculture and the State of Florida joined in funding the eradication effort. Its method depended on producing large numbers of flies, sterilizing them, and distributing them over the infested area. The aim was not to poison the landscape, but to make reproduction fail through repeated releases of sterile insects.

Production and release

The campaign’s logistics were built around a specially constructed fly factory, which produced about 50 million screwworms each week. Twenty light airplanes carried out prearranged flight patterns for five to six hours a day. Each plane carried a thousand paper cartons, and each carton held between 200 and 400 irradiated flies. The method’s biological premise thus required an industrial rhythm of breeding and irradiation, joined to systematic aerial distribution.

The cold winter of 1957–58 unexpectedly improved the timing. Freezing temperatures reduced screwworm populations in northern Florida and confined them to a smaller area, offering an opportunity to begin the program when the pest was less widespread. By the time the campaign was considered complete, after 17 months, 3.5 billion artificially reared, sterilized flies had been released over Florida and sections of Georgia and Alabama.

Eradication and its evidence

The account marks the final phase through a sequence of diminishing signs. The last known animal-wound infestation attributable to screwworms occurred in February 1959. Several adults were captured in traps during the following weeks; after that, no trace could be discovered. The progression—from the final infestation, to isolated trapped adults, to no further detection—provides the reported basis for declaring the Southeast infestation eradicated.

The book characterizes the outcome as a triumphant demonstration of scientific creativity, supported by thorough basic research, persistence, and determination. That praise is specific to the method and campaign described: the achievement came through mass releases of sterile flies, not through a claim that every screwworm population had been eliminated everywhere.

The barrier and the unfinished problem

A quarantine barrier in Mississippi was intended to prevent screwworms from re-entering the Southeast from the Southwest, where the pest remained firmly established. The barrier makes the limits of the victory clear. The regional campaign had removed the infestation from its target area, but it could not by itself prevent movement back from outside that area.

Eradication in the Southwest was described as a formidable undertaking because of the vast territory involved and the likelihood of reinvasion from Mexico. The Department nevertheless appeared to be considering some kind of program for Texas and other infested southwestern areas, perhaps aimed at keeping screwworm populations very low rather than eliminating them outright. The Southeast campaign therefore closed with a double prospect: a demonstrated biological success, and a continuing struggle to contain a pest whose wider range made complete eradication much more difficult.