Soybean stem canker
scouted Sept. 5, 2023
- Scientific Name
- Diaporthe sp.
- Background
- Soybeans in Yadkin County, variety P39A45x, were observed with 5% of the field being affected by defoliation, dieback, yellowing, and root rot in localized patches. The symptoms were observed in high and low areas and in other fields on the site. There was heavy rain a month prior, with disease becoming present in the last 3-4 weeks. There are low amounts of yellowing, mainly wilt and browning, with leaves dropping. Lower stems are brownish/black in color, with the roots rotting quickly.
- Conclusion
- The cause was identified as soybean stem canker, caused by the fungus of the genus Diaporthe. The first symptoms are often dead plants with dried leaves that remain attached to the petioles late in the season. The diseased plants usually occur in patches within the field. Lesions start out as small reddish-brown spots at the base of a branch and then expand to form sunken cankers. In some cases, it can cause top dieback by forming a dark brown canker on the upper internodes which kills only the top of the plant. Unfortunately, there are limited management practices to implement as it is best managed with resistant varieties and crop rotation to non-host crops such as corn or wheat, as the pathogen survives in soybean residue. There is no data currently on fungicide efficacy for management.
- Resources
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- No resources have been added.
