Efficacy of Surfactant Compounds with a Sulfur Fungicide (FRAC M2) for Control of Powdery Mildew, 2024

Grapevine powdery mildew (GPM), caused by the fungal pathogen Erysiphe necator, is an economically important disease of Vitis vinifera. Three nonionic organosilicone surfactants (Cohere, Hi-Wett, and Silwet L-77) were tank-mixed in a standard sulfur spray regimen in northern Georgia (U.S.A.) on a block of ‘Chardonnay’ vines in 2024 to test their ability to increase disease suppression when combined with sulfur. Disease severity was measured on fruit and leaves. Results from this trial will help grape producers make proper management decisions for E. necator management.