ARS | Publication request: Occurrences of soybean viruses, fungal diseases, and pests in Illinois soybean rust sentinel plots

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 27, 2010
Publication Date: August 27, 2010
Repository URL: http://hdl.handle.net/10113/45536
Citation: Hobbs, H.A., Herman, T.K., Slaminko, T.L., Wang, Y., Nguyen, B.T., Domier, L.L., Hartman, G.L. 2010. Occurrences of soybean viruses, fungal diseases, and pests in Illinois soybean rust sentinel plots. Plant Health Progress. DOI:10.1094/PHP-2010-0827-01-BR.

Interpretive Summary: Disease-causing pathogens and pests of soybean were detected in Illinois from leaf samples collected by scouts from sentinel plots originally established for early detection of soybean rust. Bean pod mottle virus (BPMV) was the most common virus found (at 5, 13, and 10 sites in 2006, 2007, and 2008, respectively), and Alfalfa mosaic virus, Soybean dwarf virus, Soybean mosaic virus, Tobacco ringspot virus, and Tobacco streak virus were each found in single sentinel sites in single years. Separate intensive surveys of 5 to 8 Illinois counties yielded more incidences of the less common viruses, suggesting that use of sentinel plots was best for monitoring of more common pathogens like BPMV. With respect to diseases caused by bacteria and fungi, and insect pests in 2006 and 2007: Septoria brown spot, downy mildew, Cercospora leaf blight, frog eye leaf spot, soybean aphids, and whiteflies were found frequently in sentinel plots, while bacterial pustule was found infrequently. The data give indications of the prevalence of some of the most important soybean pathogens and pests in the two to three year period in Illinois, a major soybean producing state that is neighbored by states that also are large soybean producers. This information serves as a baseline for diseases and is important to soybean researchers and growers.

Technical Abstract: In Illinois in 2006, 2007 and 2008, soybean sentinel sites that were established to monitor spread of soybean rust were sampled for additional diseases and pests. Leaf samples were sent to the University of Illinois for analysis for virus, fungal and bacterial diseases, soybean aphid, and whiteflies. Bean pod mottle virus (BPMV) was the virus found most frequently, at 13, 5, and 10 locations in 2006, 2007, and 2008, respectively. Alfalfa mosaic virus, Soybean dwarf virus, Soybean mosaic virus, Tobacco ringspot virus, and Tobacco streak virus were found at single sentinel locations in single years. When compared with more intensive virus surveys involving collection of samples from multiple sites per county, use of the sentinel sites appeared to be most useful for detection of the most common virus, BPMV. Among fungal diseases, Septoria brown spot was present at all 25 sites in 2006, downy mildew at all sites except one, and frogeye leaf spot in 15 of 25 sites. Soybean aphid was present in 8 of 25 sites and bacterial pustule at 1 of 25 in 2006. In 2007, Septoria brown spot was present in 26 of 27 sites, Cercospora leaf blight in 24 of 27 sites, frogeye leaf spot in 21 of 27 sites, downy mildew in 18 of 27 sites, soybean aphid in 15 of 27 sites, and whiteflies in 14 of 27 sites.