Soybean stem canker
scouted Sept. 2, 2025
- Scientific Name
- Diaporthe sp.
- Background
- Soybeans planted on May 10th in Person County were being scouted, and it was observed that patches in 10% of the field were showing signs of browning and yellowing between the veins, as well as root rot and stem rot. Symptoms started three and a half weeks ago, with one spot appearing on the farm and then spreading to multiple places. There were no seed treatments applied, and fungicides haven't been applied either. A sample was submitted to the PDIC for diagnosis.
- Conclusion
- Diaporthe sp. 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 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
