|Van Rij, N|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2007
Publication Date: 11/1/2007
Citation: Miles, M.R., Levy, C., Morel W., Mueller, T., Steinlage, T., van Rij, N., Frederick, R.D., Hartman, G.L. 2007. International fungicide efficacy trials for management of soybean rust. Plant Disease. 91(11):1450-1458. Interpretive Summary: The efficacy of fungicides in managing soybean rust was evaluated in early and late application protocols in 12 locations in South America and southern Africa during three growing seasons from 2002 to 2005. All of the fungicides that were evaluated in the trials reduced soybean rust severity when the epidemics were not severe, but the triazole and triazole plus strobilurin products had the largest reduction in disease severity and highest yields when soybean rust was severe. There were also differences between the early and late application protocols for many of the fungicides. Three applications were needed to manage the disease and protect yield with some fungicides. This research reports on the efficacy of fungicides compared in common trials that are available for use in the management of soybean rust in the U.S. This information is important to producers, consultants and extension specialists in the development of management strategies for the control of soybean rust.
Technical Abstract: The efficacy of fungicides in managing soybean rust was evaluated in early and late application protocols in 12 locations in South America and southern Africa during three growing seasons from 2002 to 2005. There were differences in final soybean rust severity, defoliation, yield and 1000 seed weight among the treatments at most locations. There were also significant treatment by location interactions during each of the years. These interactions were due to differences in environments that influenced yield as well as disease onset and development at each location. All the products evaluated reduced soybean rust severity when the epidemics were not severe, but the triazole and triazole plus strobilurin products reduced disease severity and had the highest yields when soybean rust was most severe. There were also differences in yield and soybean rust severity between the early and late application protocols of several treatments when soybean rust was severe, as the early application protocol had lower yields and more severe disease.