Microorganisms show promise in battle against scab
Washington D.C., August 21 -- Naturally occurring microorganisms could be used to control "scab," a fungal disease that has cost U.S. farmers over $3 billion in the last 10 years, researchers reported here today at the 220th national meeting of the American Chemical Society, the world's largest scientific society.
Scab -- known among crop scientists as fusarium head blight or FHB -- threatens millions of acres of wheat, barley and rye each year.
Current strategies to combat FHB are limited, says David Schisler, Ph.D., a plant pathologist with the U.S. Department of Agriculture in Peoria, Ill. "Many chemical fungicides are too toxic to use, especially since the blight hits toward the end of the growing season right before the harvest," he explains. "Resistant wheat varieties are only partially resistant -- nothing that can be considered immune."
In collaboration with Naseem Kahn, Ph.D., and professor Michael Boehm, Ph.D., both of Ohio State University, Schisler tested six strains of bacteria and yeast isolated from wheat plants, and found that they reduced the severity of FHB by as much as 56 percent.
The effectiveness of the microorganisms depends in part on their ability to take in choline, a carbon source in wheat that acts as a stimulant for the fungus that causes FHB.
Farmers can safely apply a biological control agent, or "microbial spray," to a crop close to harvesting time because it simply increases the concentration of naturally occurring bacteria.
No biological method of controlling FHB currently exists, but such an approach could fit well with "integrated management" of the disease, says Gary Bergstrom, a professor in the Department of Plant Pathology at Cornell University. A microbial spray, for example, could reduce the amount of chemical fungicide required to control the disease.
The tests were conducted on durum wheat and soft red winter whea
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Contact: Charmayne Marsh
y_marsh@acs.org
202-872-4445
American Chemical Society
21-Aug-2000