Soybean stem canker
scouted Oct. 15, 2024
- Scientific Name
- Diaporthe sp.
- Background
- Soybeans in Brunswick County, variety Revere 4821 XFS, were planted using 120 bags. Yields across the field ranged from 65–80 bu/A, except for a 7.8-acre section. This area is surrounded by trees and houses, although in previous years it has produced good yields of soybeans and other crops. Normal herbicide and insecticide treatments were applied, and the crop appeared healthy at desiccation. However, when moisture was checked, it was observed that the pods contained no beans. The soybeans looked normal throughout the season. A plant sample was collected for further evaluation.
- 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
