WASHINGTON, September 10, 2008--Two Agricultural Research Service (ARS) scientists have earned a place in the agency's Science Hall of Fame for research accomplishments that include devising farm practices that protect water quality and discovering new types of plant disease organisms. ARS is a scientific research agency of the U.S. Department of Agriculture.
"These two researchers exemplify the spirit of scientific excellence and creativity with which ARS has served the nation and the agricultural community since the agency's inception 55 years ago," said ARS Administrator Edward B. Knipling.
ARS began its Hall of Fame program in 1986 to recognize agency researchers for their outstanding achievements in agricultural science and technology. Inductees are nominated by their peers and must be retired, or eligible to retire, to receive the honor.
Sharpley's 28-year career with ARS began at the National Agricultural Water Quality Laboratory in Durant, Okla., where he worked from 1978 until 1995, when he transferred to the agency's Pasture Systems and Watershed Management Research Unit in University Park, Pa. Sharpley retired from ARS in 2006.
Sharpley pioneered research characterizing how the management of farmland affects the loss of phosphorus and nitrogen in runoff and by a process called leaching. He also devised soil- and water-conservation strategies that were both innovative and cost-effective for farmers to use in safeguarding water quality, while maintaining a productive agriculture.
Sharpley is widely credited with spearheading the development, supporting science and refinement of the "Phosphorus Index," a tool to identify the risk of phosphorus loss from agricultural fields. The index is used throughout the United States as well as in other countries to guide farm-nutrient management planning. His research recommendations and technological innovations have been widely adopted by regulatory and resource conservation agencies worldwide. Sharpley has authored or co-authored more than 500 scientific publications and is a fellow of the American Society of Agronomy and Soil Science Society of America.
Davis, a National Academy of Sciences member and research leader of the ARS Molecular Plant Pathology Laboratory in Beltsville, Md., has been with the agency for 40 years. At the start of his career, he created a paradigm shift in the field of plant pathology with his publication of a paper reporting the discovery of an entirely new type of microorganism, which he named "spiroplasmas" for their spiral or coiled appearance.
Davis overcame initial scientific skepticism with a mounting tide of evidence in support of his discovery. Now, spiroplasmas are known to cause diseases of not only crops, but also of harmful and beneficial insects and species of crab and shrimp.
He showed that some spiroplasmas could survive outside the cells of host plants on their flower petals. He has also found them causing diseases in honey bees and other insect pollinators. Davis' research and discoveries necessitated a revision of plant pathology textbooks and graduate-level courses for aspiring scientists. Continued investigations by Davis' group into mystery pathogens--including so-called "phytoplasmas"--led to innovative new methods of detecting, classifying and describing these unusual bacteria.