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)
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Upcoming Events
Managing the Invasive Swede Midge Webinar
March 6, 2026
Swede midge is an invasive fly that causes serious economic losses to brassica crops. Due to its small size and hidden feeding habits, swede midge is often called an "invisible pest" and damage may be misdiagnosed. In this webinar, we will review the swede midge life cycle and crop damage symptoms, current management recommendations, new research findings, and highlights from on-farm case studies with a focus on organic management.
1.75 DEC pesticide recertification credits in categories 1a, 10, and 23.
Good Agricultural Practices (GAPs) Food Safety Training
March 10, 2026
Newark, NY
Learn about food safety on the farm! This event hosted by the Cornell Vegetable Program, Cornell Lake Ontario Fruit Team, CCE Wayne County, and the NYS Department of Agriculture, will cover good agricultural practices (GAPs) to help reduce the risk of microbial contamination on the farm, keeping food and consumers safe.
Urban Ag Food Safety Webinar
March 11, 2026
Urban and small-scale producers are encouraged to join us for the Urban Ag Food Safety webinar, featuring speakers from Cornell Cooperative Extension and Cornell IPM. We will explore the 'why' behind food safety, providing a basic overview and diving into specific urban ag considerations including water, pest, rodent, and soil health challenges. We will touch on the regulation and marketing landscape, and share resources for learning more. Bring your questions!