Phyllosticta Leaf Spot of Soybean

Phyllosticta leaf spot of soybean

Phyllosticta leaf spot is caused by the fungus Phyllosticta sojicola. Lesions most often occur on leaves and are circular, oval, and irregular or V-shaped. Lesions appear gray or tan and have a narrow, dark margin. In older lesions, numerous small, black specks (i.e., pycnidia) may be visible.

The fungus likely survives in infested crop residue and can be seed transmitted. Cool, moist conditions favor disease development.

Crop rotation and tillage will reduce survival of the fungus. Phyllosticta leaf spot lesions. Image: D. Mueller

Small, black pycnidia may be observed in older lesions. Image: A. Sisson 

Gallery Images: D. Mueller and A. Sisson

Related Articles

Southern Blight of Soybeans

Southern blight is caused by a soilborne...

Soybean Rust of Soybean

Soybean rust symptoms are most common af...

Aerial Blight of Soybean

Aerial blight (also known as Rhizoctonia...

Tobacco Ringspot of Soybean

Symptoms caused by Tobacco ringspot viru...

Wildfire of Soybeans

Wildfire of soybeans is an uncommon bact...