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
Vegetable Pest and Cultural Management Field Meeting for Auction Growers -- Ontario Produce Auction

July 15, 2025
Stanley, NY
This evening meeting will demonstrate pest management in fresh market vegetables in both field and greenhouse (high tunnel) vegetables, primarily for those growing for wholesale auction. A hands-on demonstration of weed, insect and disease identification in vegetables including management options. Details on each topic will focus on field observations at the farm.
Orleans Summer Vegetable Meeting, 2025

July 16, 2025
Waterport, NY
Meeting themes are pest management in a wide array of produce and best practices for pesticide use. Professor Brian Nault will cover allium leaf miner and thrips in onions, garlic, and leeks, and discuss insect challenges in other crops. Bring your questions! We'll also have a field walk that includes high tunnel tomato and cucumber.
DEC credits available: 0.5 in CORE plus either 1.25 in 1a and 23, or 0.75 in 24.
Vegetable Pest and Cultural Management Field Meeting for Auction Growers -- Finger Lakes Produce Auction

July 18, 2025
Penn Yan, NY
This evening meeting will demonstrate pest management in fresh market vegetables in both field and greenhouse (high tunnel) vegetables, primarily for those growing for wholesale auction. A hands-on demonstration of weed, insect and disease identification in vegetables including management options. Details on each topic will focus on field observations at the farm.