2026 Onion Fungicide Cheat Sheet for Control of Leaf Diseases
Christy Hoepting, Extension Vegetable Specialist
Cornell Vegetable Program

The 2026 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.

Upcoming Events
Vegetable Pest and Cultural Management Field Meeting for Auction Growers -- Chautauqua
July 14, 2026
Panama, NY
A field walk will demonstrate pest management in fresh market vegetables in both field and greenhouse (high tunnel) vegetables, primarily for those growing for wholesale auction. CCE Cornell Vegetable Program Specialist Judson Reid will identify weeds, insects and diseases in vegetables and will go over management options such as inter-row cover crops, grafting, and where appropriate, spray options.
DEC recertification credits will be offered.
Vegetable Pest and Cultural Management Field Meeting for Auction Growers -- Allegany
July 15, 2026
Fillmore, NY
A field walk will demonstrate pest management in fresh market vegetables in both field and greenhouse (high tunnel) vegetables, primarily for those growing for wholesale auction. CCE Cornell Vegetable Program Specialist Judson Reid will identify weeds, insects and diseases in vegetables and will go over management options such as inter-row cover crops, grafting, and where appropriate, spray options.
DEC recertification credits will be offered.
Pest Management for Small-Scale Growers
July 23, 2026
Rochester, NY
Join us for a hands-on field day exploring integrated pest management tools for small-scale growing spaces and the opportunity to build community with local growers! Learn the best practices for using row covers, biocontrols, trapping, and more.