Diaporthe phaseolorum var. caulivora is a fungus that causes stem canker disease of soybean. The fungus forms a dark canker at the node of a diseased stem (Figure 1) and as the canker enlarges it eventually girdles the stem killing the tissues above the canker. Stem canker is a disease of considerable economic importance in the north central portion of the United States. The fungus has been observed attacking more than 70 percent of the plants in severely diseased fields in Iowa. Prior to 1948 stem canker was confused with the pod and stem blight disease of soybean, caused by Diaporthe phaseolorum var. sojae, until Welch and Gilman (1948) made a distinction between the 2 fungi on a basis of morphological characteristics and pathogenicity. Athow and Caldwell (1954) confirmed the fact that D. phaseolorum var. caulivora was considerably more pathogenic than D. phaseolorum var. sojae, and reported that up to 40 percent of the plants were killed by the former fungus in some fields in Indiana. Hildebrand (1953) has also reported the disease serious in Ontario, Canada.
Proceedings of the Iowa Academy of Science
©1955 Iowa Academy of Science, Inc.
"Susceptibility of Soybean Petioles to Attack By Diaporthe Phaseolorum Var. Caulivora,"
Proceedings of the Iowa Academy of Science, 62(1), 104-108.
Available at: https://scholarworks.uni.edu/pias/vol62/iss1/11