Neocosmospora stem rot
scouted Sept. 26, 2024
- Scientific Name
- Neocosmospora vasinfecta
- Background
- Soybeans in Cumberland County were scouted, and it was observed that about 30% of the field was affected by randomized browning. The previous year (2023), the field was planted with tobacco and treated with Command 3E as well as Spartan herbicides. In 2024, soybeans were planted after a burndown of the ryegrass cover crop in May. Velum was applied at planting (4 oz/acre), along with Gromolone and Envive herbicides. Follow-up herbicides included Roundup and Liberty. The first insecticide application consisted of bifenthrin and boron, while the second insect spray was Beleaf. The soybean seed was untreated. Issues were present during early season but began to look better. After Tropical Storm Debbie, issues progressed and continued to worsen following heavy rainfall in late September. The field is very sandy, yet still held a large quantity of water. Samples submitted include plants from multiple locations, including both healthy and affected areas.
- Conclusion
- The issue was confirmed to be Neocosmospora stem rot, caused by the fungus Neocosmospora vasinfecta. Symptoms of Neocosmospora root and stem rot can include interveinal chlorosis on the foliage, the presence of small red fungal structures around the crown, and discoloration of the pith. These signs can resemble other stem diseases, especially red crown rot. As interveinal chlorosis progresses, lower leaves may begin to drop earlier than expected. Both the roots and pith may also show varying degrees of discoloration.
- Resources
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- No resources have been added.
