6-28-2005 |
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PRODUCTS APPROVED TO FIGHT SOYBEAN DISEASE The West Virginia Department of Agriculture's (WVDA) request to the U.S. Environmental Protection Agency (USEPA) to allow four antifungal chemicals to be used against soybean rust (SBR) has been approved. SBR is a plant disease that first appeared in the United States last year and has since been discovered in states across the South. Although it has not been detected in West Virginia, it is possible that it could make an appearance later in the summer. "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 soybean farmers informed on what to look for and what can be used to treat this disease." SBR is a serious disease of soybeans caused by the fungus Phakopsora pachyrhizi. Until recently this disease did not occur on soybean in the Western Hemisphere, but it spread to South America in 2001 and was found for the first time in North America in November 2004. Experts believe it may have been carried to this country on winds from last summer's hurricanes. Symptoms begin on the lower leaves of the plant as small lesions that increase in size and change from gray to tan or reddish brown on the undersides of the leaves. Lesions are most common on leaves, but may occur on petioles, stems and pods. Of the two types of lesions, the tan lesions, when mature, consist of small pustules surrounded by slightly discolored necrotic area with masses of tan spores on the lower leaf surface. Reddish brown lesions have a larger reddish brown necrotic area, with a limited number of pustules and few visible spores on the lower leaf surface. Once pod set begins on soybeans, infection can spread rapidly to the middle and upper leaves of the plant. High levels of infection in soybean fields result in a distinct yellowing and browning of fields. Environmental conditions impact the incidence and severity of SBR. Prolonged leaf wetness combined with temperatures between 59 and 86 degrees Fahrenheit and humidity of 75 to 80 percent is required for spore germination and infection. EPA has given emergency approval of four chemicals to control SBR: tetraconazole, trifloxystrobin, propiconazole and myclobutanil. Brand names that contain these chemicals include: Folicur 3.6F, Orius 3.6F, Headline SBR, Stratego, Tilt, Propimax, Bumper, Quilt, Laredo EC, Laredo EW, Domark 230 ME. For more information, contact WVDA's Plant Industries Division at 304-558-2212.
The West Virginia Department of Agriculture protects plant, animal and human health through a variety of scientific, regulatory and consumer protection programs, as mandated by state law. The Commissioner of Agriculture is one of six statewide elected officials in West Virginia. Currently, Commissioner Gus R. Douglass is the longest-serving agriculture commissioner in the nation. For more information, visit www.wvagriculture.org. |
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