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

Bacterial Pustule of Soybean

Bacterial pustule occurs mid- to late se...

Soybean Dwarf of Soybean

Symptoms caused by Soybean dwarf virus (...

Downy Mildew of Soybean

Downy mildew of soybean is common but se...

Soybean Mosaic of Soybean

Foliar symptoms caused by Soybean mosaic...

Soybean Rust of Soybean

Soybean rust symptoms are most common af...