Above: Pustules (spores) magnified by 20X hand lens. Below: Symptoms on upper leaf surface.

Asian soybean rust, Phakopsora pachyrhizi, better known as soybean rust (SBR) was first reported in Japan in 1903. The first known infection of SBR in the United States occurred in 1994 in Hawaii. The first confirmed incident of the disease in the continental United States occurred in Louisiana on November 10, 2004. By the end of 2005, SBR had been confirmed in Tennessee, Louisiana, Alabama, Arkansas, Florida, Georgia, Mississippi, Missouri, Texas, North Carolina and South Carolina. One infectious lesion on kudzu was found in Kentucky in November, which did not have any significant impact on soybeans. Besides the U.S., the disease is currently found in Africa, Asia, Australia, and South America. SBR has yet to be detected in West Virginia.

“There is some doubt as to whether the spores of this fungus can survive West Virginia's winter weather," said Commissioner of Agriculture Gus R. Douglass. "However, it could migrate from other states during the warmer months and we want to keep our farmers informed on what to look for and what can be used to treat this disease.”

Federal investigators believe the airborne spores from soybean rust may have been transported from South America to the southeastern United States during the intense tropical season of 2004. Spores are disseminated through wind patterns and deposited by rain storms moving from south to north. Generally, symptoms of SBR begin as small brown or red-brick lesions on the upper leaf surface of lower leaves on the soybeans. Infection can spread rapidly up through the mid-canopy if left untreated.

The West Virginia Department of Agriculture (WVDA), in cooperation with the United States Department of Agriculture (USDA), established five sentinel plots in 2005, concentrating on larger soybean producing areas in West Virginia. Sentinel plots are aimed for early detection of soybean rust, to track the movement of rust from the South, and to assess the overwintering capability of SBR in the southern states.

This year, the WVDA, in cooperation with the USDA, are planning to establish seven sentinel plots in West Virginia using both early and late maturing varieties of soybeans. In addition to soybeans, kudzu growing in the southern portion of the state will be monitored for possible latent infections. The WVDA will also be performing preliminary diagnostic testing of suspected SBR samples for this year's growing season.

The USDA has also entered their second year with the Pest Information Platform for Extension and Education (PIPE) website: http://www.sbrusa.net/. The site last year was known as the “soybean rust” website. This interactive website gives soybean growers the opportunity to monitor and track SBR. Updated commentaries and management guidelines are additional tools provided on this site for growers to use.

" West Virginia grows approximately 16,000 acres of soybeans, and we want farmers to be on the lookout for any sign of the disease so that we can document any spread of the disease nationally," said Gary Gibson, Director of WVDA's Plant Industries Division. "This species can dramatically decrease soybean yields - as high as 80 percent in some cases - so it's important that we do not let our guard down,” Gibson said.

For more information, contact the WVDA's Plant Industries Division at 304-558-2212.