WA Wine | WAVEx Webinar | Sulfur Fungicide Phytotoxicity | June 10, 2026
Dr. Michelle Moyer of Washington State University and her graduate student, Jesse Stevens, ran a series of field experiments to address the longstanding conventional wisdom about not spraying sulfur fungicide in the heat because of a risk of phytotoxicity, or ‘burn.’ They were able to bust a myth and explain the roles of sulfur, of spray adjuvants, and of the weather–heat and humidity.