Cercospora leaf blight
scouted Sept. 26, 2024
- Scientific Name
- Cercospora kikuchii
- 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 identified as Cercospora blight of soybean. This disease is caused by the pathogen Cercospora kikuchii and although it's common in soybeans it rarely causes significtant yield losses in North Carolina. Chemical management and cultural practices are both options to control Cercospora leaf blight.
- Resources
