Developed in the 1950’s by Drs. Raymond Bushland and Edward Knipling (USDA), the Sterile Insect Technique (SIT) is one of biological control’s greatest success stories. Prior to that time, the screw worm (Cochliomyia hominivorax), a parasitic fly whose maggots eat the living tissue of warm-blooded animals, seemed unstoppable. Not only was wildlife affected, but the cattle industry reported annual losses of $200 M in the U.S. alone. Human beings were also victims which could not have been pleasant.
Bushland was intrigued with Knipling’s theory of “autocidal control” – – somehow interrupting the pest’s lifecycle. They settled on the idea of eradiating, and thus sterilizing, large numbers of male screw worm flies and releasing them into the wild. The sterile males would mate with the short-lived females and prevent production of viable eggs. Sanibel Island, Florida was the first test site, followed by Curacao, Venezuela. The results were profound. Ultimately, the screw worm fly was eradicated from North America. Subsequently, SIT has been used successfully on many insect pests, most notably the Medfly (Ceratitis capitata) and Painted Apple Moth (Teia anaretodes).
Could a Sterile “Mollusk” Technique (SMT?) work on invasive apple snails? Dr. John Teem of FDACS’s Division of Aquaculture is optimistic, but he tempers that hopefulness with the fact that his research is in an early stage. “First, we have to determine the optimal radiation dose. The ideal dose is one that creates a sterile snail without impairing its mating behavior.” Then come mating assays, field trials, etc. He warns that there is still plenty of work to do, but says, “I think it will work!” Well, good luck, John. That would be an elegant solution! Posted by Jess Van Dyke
For more information, contact Dr. John Teem at email@example.com
FDACS’ Division of Aquaculture: http://www.floridaaquaculture.com/