Evaluation of Potential Phytotoxicity of Avelyo for the Control of Powdery Mildew in Lettuce in a Greenhouse Hydroponic Production System in Mississippi, 2025

Powdery mildew, caused by Golovinomyces cichoracearum, is one of the most common fungal diseases in greenhouse production of lettuce. Symptoms include chlorotic and deformed leaves with signs of powdery coating on the leaves. Fungicides have become one of the most important components in powdery mildew management. This report evaluates the potential phytotoxicity effects of Avelyo at two application rates for the control of powdery mildew in greenhouse lettuce. The trial was conducted at the North Mississippi Research and Extension Center, Verona, MS, in 2025. Phytotoxicity, plant growth, and yield were evaluated for all treatments. Results from this trial will help advise greenhouse lettuce growers in minimizing phytotoxicity while managing powdery mildew using fungicides.