Bean Binoculars Incident

Frogeye Leaf Spot

Issue: Pathogen

Scouted in Cumberland County, NC on July 4th, 2024

Frogeye Leaf Spot

Details:

Small, circular lesions were observed on R4 (full pod) soybeans, identified as Frogeye Leaf Spot (FLS). FLS is commonly observed in North Carolina and is caused by Cercospora sojina K. hara. Other symptoms may include water soaked lesions, which, as they expand, become brown or grey in color with a yellow halo around them. FLS favors warm and humid environments. This site has consistently been in the high 80s to mid 90s, and has received adequate rainfall in the past few weeks.

Conclusion:

Fungicide applications for FLS are most effective when they are applied between the R3 and R5 growth stages. Other management recommendations for future years include crop rotation with non-host crops, planting resistant varieties, and using other integrated pest management strategies. You can learn more about FLS in soybeans in this article and about general disease management in this article, both from NC State Extension. 

Resources:

Frogeye Leaf Spot | NC State Extension
Disease Management | NC State Extension

Photo of a hand pinching the edge of a soybean trifoliate that contains Frogeye Leaf Spot. Photo of a soybean plant showing symptoms of Frogeye Leaf Spot.