Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2011
Publication Date: 11/1/2011
Citation: Isard, S., Barnes, C., Hambleton, S., Ariatti, A., Russo, J., Tenuta, A., Gay, D., Szabo, L.J. 2011. Predicting soybean rust incursions into the North American continental interior using crop monitoring, spore trapping, and aerobiological modeling. Plant Disease. 95(11):1346. Interpretive Summary: Soybean rust caused by the obligate fungal plant pathogen Phakopsora pachyrhizi is regarded as the most destructive foliar disease of soybean (Glycine max). Spores that can be transported long distances in the atmosphere spread the disease. The arrival of soybean rust pathogen in the U.S. was likely due to spores being blown by winds from northern South America and deposited by rain associated with Hurricane Ivan. Control of this disease is based on the application of fungicides to infected fields to reduce the development of the disease and to uninfected fields as a preventative measure. The dissemination of information on disease development and risk assessment in a timely and cost effective means is critical to sustainable control of this disease. Analysis of rain deposition of soybean rust spores, aerobiology model output and field observations of soybean rust spread in 20007 and 2008 showed a strong correspondence between spore collections and model predictions for the continental interior of north America where the primary product of soybeans occur. The current reduction of soybean rust in the U.S. is likely due to the effective control of this disease in the southern states through information delivered by the Integrated Pest Management Pest Information Platform for Extension and Education (ipmPIPE) network. The analysis further suggests that spore trapping and aerobiology modeling can reduce the reliance on costly field plot monitoring in the continental interior of North America while maintaining the effectiveness of the ipmPIPE system for management of soybean rust.
Technical Abstract: Between 2005 and 2009, millions of U.S. and Canadian soybean acres that would have received fungicide application remained untreated for soybean rust due to information disseminated through the Integrated Pest Management Pest Information Platform for Extension and Education (ipmPIPE), increasing North American producers’ profits by $100s of million each year. The results of our analysis of Phakopsora pachyrhizi urediniospores in rain collections, aerobiology model output, and observations of soybean rust spread in 2007 and 2008 show a strong correspondence between spore collections and model predictions for the continental interior of North America where soybean is an important crop. The analysis suggests that control practices based on the information delivered by the ipmPIPE may have suppressed the number and strength of inoculum source areas in the southern states and retarded the northward progress of seasonal soybean rust incursions into continental North America. The analysis further suggests that spore trapping and aerobiological modeling can reduce our reliance on the costly Sentinel Plot Network while maintaining the effectiveness of the ipmPIPE system for soybean rust management.