Powdery Mildew (fungi – Erysiphe spp.)

Host Grass: Perennial Ryegrass(Lolium perenne), Poa Series(Poa sp.)

Cause and Symptoms: Powdery mildew is especially common on annual grasses used for overseeding. It spreads rapidly in shaded areas. Powdery mildew appears as a grayish-white fungal growth on the upper surface of leaves and leaf sheaths. Infected leaves turn yellow and gradually die. Repeated infestations result in eventual death of plants. Surviving plants are weakened.

Control and Management:  Reduced shading and increased air circulation will help control powdery mildew. Where these conditions cannot be changed, fungicides are available for control.

Content edited by: Young-ki Jo, ykjo@tamu.edu , Assistant Professor and Extension Specialist, Dept Plant Pathology & Microbiology, Texas A&M University, Texas AgriLife Extension Service, May 31, 2013