Effects of Individual and Multiple Infections with Three Bacterial Pathogens on Disease Severity and Yield of Soybeans. Ingyu Hwang, Department of Plant Pathology, U.S. Department of Agriculture, and Department of Plant Pathology, University of Illinois, Urbana 61801. S. M. Lim, Agricultural Research Service, U.S. Department of Agriculture, and Department of Plant Pathology, University of Illinois, Urbana 61801. Plant Dis. 76:195-198. Accepted for publication 10 September 1991. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source, The American Phytopathological Society, 1992. DOI: 10.1094/PD-76-0195.

Bacterial blight, bacterial pustule, and wildfire resulting from multiple inoculations with individual or mixed cultures had no effect on yield of three soybean (Glycine max) cultivars (Pella, Williams, and Cumberland or Wells) in 1986 and 1987. In both years, disease severity at each rating and area under the disease progress curve (AUDPC) of Pella, which is susceptible to Xanthomonas campestris pv. glycines, causal agent of bacterial pustule, were highest in the plots inoculated with either X. c. glycines alone or combination with the other pathogens, Pseudomonas syringae pv. glycinea (bacterial blight) and P. syringae pv. tabaci (wildfire). The severity of individual diseases was not affected by mixed inoculations with the other pathogens; the pathogens did not act synergistically. Effects of individual and multiple diseases on yield were not statistically significant.