2025 Onion Fungicide Cheat Sheet for Control of Leaf Diseases
Christy Hoepting, Extension Vegetable Specialist
Cornell Vegetable Program

The 2025 Cornell Onion (Dry Bulb) Fungicide "Cheat Sheet" for Control of Leaf Diseases in New York provides relative performance rankings for Botrytis leaf blight and Stemphylium leaf blight of the main fungicide options that may be used in New York to control these diseases, based on recent on-farm fungicide trial results, which reflect reduced efficacy of SLB due to development of fungicide resistance. It includes active ingredients, FRAC codes, rating for risk of fungicide resistance, activity on downy mildew, maximum use rates, and photos.
2025 Onion Fungicide Cheat Sheet for Control of Leaf Diseases in New York (pdf; 352KB)

Upcoming Events
2025 Potato Advisory Meeting
December 16, 2025
Canandaigua, NY
Come hear the latest on insect pest control and fertility management in potatoes from Cornell University experts. Potato variety trial updates will be shared too. After lunch will be the Empire State Potato Grower's Meeting. 1.5 DEC credits in 10, 1a, and 23.