Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2002
Publication Date: N/A
Interpretive Summary: Phomopsis seed decay of soybean is a fungus disease that attacks soybean seeds and causes a reduction in seed germination; infected seeds often suffer other quality losses compared to non-infected seeds. The objectives of this research were to determine the effects of herbicides and seedborne pathogens on different soybean seed quality parameters, and to determine the effect of herbicides on the presence of seedborne pathogens of plots located throughout Illinois. Herbicides had little or no effect on germination, incidence of seed pathogens, and protein and oil concentrations. Phomopsis seed decay caused a reduction in seed germination. This report is of interest to soybean pathologists, seed dealers, farm managers, and growers since it provides information about the interaction of herbicides, seed germination, and soybean seed decay organisms.
Technical Abstract: Field plots planted to different soybean cultivars located at four locations in Illinois were established between 1997 and 2000. Different weed management treatments were applied to the soybean plants, and varied from handweeded to preemergence herbicides to postemergence herbicides, and soybean seed was harvested and evaluated for different seed quality parameters. Herbicides had little or no effect on seed quality parameters such as percentage germination, incidence of seed pathogens, and protein and oil concentrations. Soybean seed quality was affected by Phomopsis spp. and Cercospora kikuchii in that there were significant (P = 0.05) inverse correlations between Phomopsis spp. incidence and percentage seed germination, C. kikuchii incidence and percentage seed germination, and C. kikuchii incidence and oil concentration. A significant (P = 0.05) inverse relationship between Phomopsis spp. incidence and C. kikuchii incidence was also detected.