A sterile male screwworm fly marked with a numbered tag to study fly dispersal, behavior, and longevity. Photo by Peggy Greb, USDA-ARS, Bugwood.org.

Dr. Bushland was an ESA Honorary Member and President of ESA’s Southwestern Branch. Dr. Knipling was an ESA Fellow and an Honorary Member. Both scientists were selected to deliver the Founders’ Memorial Presentation at ESA annual meetings, and Dr. Knipling is the subject of the 2016 Founders’ Memorial Presentation.

The two researchers will be posthumously honored later this year for their study of the “sex life of the screwworm fly.” The U.S. Department of Agriculture-funded work led to a novel pest control technique and the eradication of the screwworm (Cochliomyia hominivorax) in North and Central America, saving ranchers in the South and consumers billions of dollars over the past 50-plus years.

Though most Americans today are not familiar with the screwworm fly, prior to the 1960s, ranchers in the southern U.S. were locked in a constant struggle against the deadly insect. Female screwworms lay their eggs in the wounds of cattle, livestock, and even humans. The eggs hatch into maggots that feed on wounded flesh. The maggots can kill a full-size cow in less than two weeks. The pests cost ranchers hundreds of millions of dollars each year in lost livestock and pest management prior to Knipling and Bushland’s innovative sterile insect technique.

Working at field stations in Texas and Florida in the early 1930s-1950s, Knipling, Bushland, and their colleagues did much of their research on a shoestring budget and in the face of ridicule. When they shared their idea to use sterilized males to overwhelm wild screwworm flies and cause the population to collapse through natural mating behavior, their approach was met with skepticism from peers who said “you just can’t castrate enough flies.” Inspired by the work of Nobel Laureate geneticist Hermann J. Muller, the two demonstrated that they could inflict mass sterilization of insects through irradiation — a feat widely lauded as one of the most important developments in pest control and one of the first peaceful uses of nuclear radiation. In 1953, after an unexpected request from a Dutch official on the island of Curacao, the researchers completed the first, full-scale field test of the technique on the island. After just three months, not a single sterile egg could be found on the island. The much maligned technique worked even better than predicted.

The USDA, with support from state governments and local communities, launched a larger scale effort to eradicate the screwworm fly throughout the southern U.S. By 1982, the screwworm fly had been eradicated across the United States. Since then, the USDA has partnered with countries throughout Central America to wipe out the flies to Panama, where today it maintains a border zone to prevent re-infestation from South America. The eradication effort has cumulatively saved U.S. meat and dairy suppliers billions of dollars over the past 50-plus years, thanks to a modest investment of $250,000 in basic research on screwworm flies.

Knipling and Bushland were honored with the 1992 World Food Prize for their groundbreaking work — just one of many accolades the two have received in recognition of their contributions to pest control and the eradication of screwworm fly in North and Central America. The work has given U.S. consumers an estimated 5 percent reduction in the price of supermarket beef. In the developing world, the pest control technique is a crucial component of food security and public health. The international screwworm eradication program is now cited as a textbook example of basic science producing enormous returns.

Read more at:

– Golden Goose Awardees: Edward F. Knipling and Raymond C. Bushland

– 1992 World Food Prize: Knipling and Bushland

– The Development and Application of the Sterile Insect Technique (SIT) for New World Screwworm Eradication