Submitted to: Integrated Pest Management Reviews
Publication Type: Other
Publication Acceptance Date: 12/17/2004
Publication Date: 12/21/2004
Citation: Miles, M.R., Morel, W., Steinlage, T., Hartman, G.L. 2004. Summary of The USDA Fungicide Efficacy Trials To Control Soybean Rust In Paraguay 2003-2004. Integrated Pest Management Reviews. Available:http://www.ipmcenters.org/NewsAlerts/soybeanrust/.
Technical Abstract: The Asian soybean rust, caused by Phakopsora pachyrhizi, is one of the most devastating diseases of soybean world wide, causing yield losses of up to 80 % in experimental plots. With the spread into South America the pathogen has become a threat to soybean production in the continental U.S. Fungicides, although not commonly used on soybean in the U.S., will be the primary management tool available to producers. The objectives of these trials were to evaluate soybean rust control and yield benefits from fungicides that are or could be registered for use in the continental U.S, including those listed in the Section 18 Emergency exemption requests submitted to the EPA. Fungicide efficacy trials were located in the Parana River basin of southern Paraguay during the 2003-2004 growing season. A total of 46 fungicide treatments were evaluated, the majority of the plots received either two or three fungicide applications but there were single application treatments as well. All compounds controlled soybean rust when compared to the untreated control; disease severity was less in all the plots treated with fungicides. Yield increases were also seen with each of the fungicides in the Section 18 Emergency exemption request. To make future trials more effective, experimental locations need to be identified where irrigation and inoculation can be provided. If natural inoculation and rainfall are relied upon to provide disease severities sufficient to evaluate fungicides then the number of locations and years of testing will need to be increased.