Cercospora sojina

Fungal Disease

Cercospora sojina

Fungal Disease

Cercospora sojina

Fungal Disease

Cercospora sojina

Fungal Disease

Warm, humid weather promotes spore production, infection, and disease development. Young leaves are more susceptible to infection than older leaves, but visible lesions are not seen on young, expanding leaves because the lesions take two weeks to develop after infection.

Infection can occur at any stage of soybean development but most often occurs after flowering and is typically in the upper canopy. Initial symptoms are small, dark spots on the leaves. Spots eventually enlarge to a diameter of about ¼ inch, and the centers of the lesions become gray to brown and have a reddish-purple margin. Individual leaf spots can coalesce to create irregular blighting patterns on the leaf.