Submitted to: Soybean Disease Compendium
Publication Type: Book / Chapter
Publication Acceptance Date: 8/10/1999
Publication Date: N/A
Technical Abstract: Soybean rust is found extensively in areas of the Eastern and Western Hemispheres. Significant losses have been reported only in the Eastern Hemisphere. Heavily infected plants have reduced seed weight, and fewer pods and seeds. The most common symptom is gray-green, tan to dark brown or reddish brown lesions with one to many erumpent, globose uredia particularly on the underside of the leaflets. Soybean rust is caused by Phakopsora meibomiae (anamorph Malupa vignae) and Phakopsora pachyrhizi (anamorph Malupa sojae). Rust epidemics are most severe when the mean daily temperature is less than 28C, with long periods of leaf wetness occurring throughout the growing season. Spread of urediniospores is by wind-blown rain. Four dominant, independently inherited genes for resistance to P. pachyrhizi have been identified. Certain fungicides can reduce rust damage, such as mancozeb and triadimefon.