2022 Cornell Onion Fungicide Cheat Sheets for Control of Leaf Diseases
Christy Hoepting, Extension Vegetable Specialist
Cornell Vegetable Program
This sheet 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.
The 2022 Onion Fungicide Cheat Sheet for Control of Leaf Diseases in New York includes active ingredients, FRAC codes, rating for risk of fungicide resistance, activity on downy mildew, and maximum use rates.
The 2022 Relative Performance of Fungicides Including Tank Mixes for Control of Botrytis Leaf Blight and Stemphylium Leaf Blight Cheat Sheet provides an easy-to-read ranking of the relative efficacy of the treatment options and their FRAC groups.
2022 Onion Fungicide Cheat Sheet for Control of Leaf Diseases in New York (pdf; 302KB)
2022 Performance of Fungicides Including Tank Mixes for Control of BLB and SLB (pdf; 276KB)

Upcoming Events
Chautauqua Region Winter Vegetable Meeting
January 30, 2026
Randolph, NY
Fresh market production meeting for small to mid-sized farms. Topics include: vegetable disease management, keeping yourself safe while spraying (organic & conventional), soil and water sampling, managing soil organic matter, grower panel, industry and programmatic updates.
DEC credits available: 1.0 in CORE plus 1.5 in 1a and 23.
Eden Area Winter Vegetable Meeting
February 4, 2026
North Collins, NY
Join us for a mix of industry updates, crop protection talks, pesticide safety programming, and fertility management discussions. This meeting is jointly hosted by the Cornell Vegetable Program and Timac Laing-Gro.
1.25 DEC credits available in CORE plus 1.75 in 1a and 23.
Orleans Regional Winter Vegetable Meeting
February 9, 2026
Albion, NY
Topics include: Breeding and evaluating tomatoes to control disease and improve yield, jar testing and ensuring spray water quality, breaking down organic matter, FSMA updates and Q&A with Ag & Markets, and industry updates. Includes hands-on learning, coffee break, and sponsor booths.
DEC credits available: 1.0 in CORE plus 0.5 in 1a, 10 or 23