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
2026 NYS Dry Bean Meeting and Cutting Event
March 20, 2026
Geneva, NY
The Cutting Event will be held in the morning, followed by lunch, and the NYS Dry Bean Meeting in the afternoon.
DEC recertification credits available for the NYS Dry Bean Meeting portion of the day: 2.0 in categories 1a, 10, 21, and 23.
Harmonized GAP Plus+ Plan Writing Session
March 20, 2026
Newark, NY
Join us for this specialized workshop to cover requirements for this specific audit. Commercial fruit and vegetable growers are increasingly being asked to have the Harmonized GAP Plus+ audit to satisfy some large buyer's requirements.
2026 Rochester Urban Agriculture Conference
March 21, 2026
Rochester, NY
Join us for our annual Rochester Urban Agriculture Conference, a day of learning and connections featuring interactive workshops, community knowledge sharing, Fruition's Gift of Seed Experience, horticulture tables and displays, and more!