Soybean stem canker
scouted July 18, 2024
- Scientific Name
- Diaporthe sp.
- Background
- Soybeans in Edgecombe County were scouted, and it was observed that 1% of the field was affected by yellowing between the veins. Plants that are yellowed have small roots and little to no nodules while normal green soybeans in the field have perfectly healthy roots. Only a small spot of the field is affected, and the field is a sunny site. A soil and tissue sample was submitted to the NCDA, in which no issue was identified. A sample was submitted to the PDIC for diagnosis.
- 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
