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United States Department of Agriculture

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1 - The Life and Vision of Edward F. Knipling Concerning the Eradication of the Screwworm
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So my father wrote to Dr. Muller (lower right) and outlined his theory. Following Muller's enthusiastic response to the idea of sterilizing large numbers of laboratory-reared screwworms, Dr. Bushland (upper right), who was then back in Texas at Kerrville, put the idea to the test. D. F. Hopkins was a key co-worker in this research. Using x-ray equipment at a nearby Army hospital in San Antonio, they exposed screwworms of different life stages to radiation, and discovered that they could be sterilized at certain doses without affecting their mating behavior or causing other serious damage. The next step was cage studies using both sterile and normal flies in various ratios. These studies confirmed the theory that reproduction of the screwworm could be inhibited at levels consistent with the mathematical probability models.
Following these exciting and promising results, larger scale screwworm fly mass rearing and irradiation capabilities were established and field testing of the sterile insect technique was initiated in 1951 on Sanibel Island, just off the west coast of Florida. This initial test was only partially successful due to the proximity of the island to the mainland which allowed reinfestation. However, in 1953 the test was repeated at a more isolated location on the Dutch West Indies Island of Curacao, off the coast of Venezuela. Within just a matter of months and about three fly generations, the test proved highly successful, resulting in the complete elimination of the native screwworm population over the entire island.
Mr. Al Baumhover was the leader of the field tests on both Sanibel Island and Curacao. You can imagine the excitement that he, my Dad, and all their co-workers felt at this success and proof of concept. Years later my Dad often reflected back and said the success at Curacao was one of the most gratifying moments of his entire professional career. Not only had the concept been proven, but he and others had overcome much adversity that was present all along the way, including skeptics, critics, opponents, and difficulty in securing financial and policy support for their research and pilot tests. However, there were others who provided encouragement and support; he was very much indebted to these people.
My Dad's persistent optimism and tenacity to overcome obstacles were among his greatest virtues. Curacao, however, was only the beginning. Word of the astounding success of the sterile insect technique in eliminating screwworms there created a ground swell of support among livestock producers in Florida who demanded an eradication program be initiated on the mainland. To make a long story short, soon afterwards, the technique was used to systematically eliminate the screwworm from all of the Southeastern United States by 1959.



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Last Modified: 8/12/2016
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