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

Brown Stem Rot of Soybean

Brown stem rot (BSR) is caused by the fu...

Bean Pod Mottle of Soybean

Foliar symptoms caused by Bean pod mottl...

Soybean Dwarf of Soybean

Symptoms caused by Soybean dwarf virus (...

Cercospora Leaf Blight of Soybean

Cercospora leaf blight is frequently see...

Frogeye Leaf Spot of Soybean

Frogeye leaf spot of soybean occurs acro...