DISEASES OF SOYBEAN – PHOMOPSIS POD AND STEM BLIGHT

Phomopsis stem and pod blight is a common late season disease of soybeans. The fungus Diaporthe phaseolorum (the asexual form is a species of the fungus Phomopsis, thus the name of the disease) causes the disease and is oftentimes found associated with healthy soybean plants. If the plants become stressed, or even sometimes as the plants normally mature, the fungus becomes active causing stem cankers and plant death. The fungus can also infect forming pods leading to small, shriveled, infected seeds. The most diagnostic characteristics of this disease are the rows of small, black dots that form on infected stems and pods. These dots are reproductive structures of the fungus that causes the disease.