2025 Onion Fungicide Cheat Sheet for Control of Leaf Diseases
Christy Hoepting, Extension Vegetable Specialist
Cornell Vegetable Program

The 2025 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.
2025 Onion Fungicide Cheat Sheet for Control of Leaf Diseases in New York (pdf; 352KB)
Upcoming Events
2026 Orleans County - DEC Certified Pesticide Applicator License Pre-Exam Training
March 9, 2026 : DEC Certified Applicator Pre-Exam Training Day 1
Albion, NY
This training is only for those with experience and does not qualify for the 30-hour official DEC training - you are exempt from the 30 hour training (and eligible for this coaching session) if you have pesticide application experience, either through working on your own farm or through employment on another farm.
March 13, 2026 : DEC Certified Applicator Pre-Exam Training Day 2
Albion, NY
This training is only for those with experience and does not qualify for the 30-hour official DEC training - you are exempt from the 30 hour training (and eligible for this coaching session) if you have pesticide application experience, either through working on your own farm or through employment on another farm.
2026 Orleans County - DEC Certified Pesticide Applicator License Exam
March 16, 2026
Albion, NY
A Certification Exam will be administered on March 16th by the DEC to Qualified Applicants. Plan to arrive by 8:30am. The fee for the exam is $100: bring a check payable to NYSDEC the day of the exam. You must register with DEC to take the exam. To register for the exam or if you have questions regarding the Certification Process, please contact Justin Schoff at the Bath DEC office (607) 622-8290.
Postharvest Water Management, Sanitation, and Traceability Workshop
March 18, 2026
Albion, NY
Cornell University personnel from the National GAPs Program and the Produce Safety Alliance are presenting a workshop on postharvest water management, sanitation, and traceability. This workshop will include a mix of short talks and hands-on activities to provide attendees with applied experience with sanitation, postharvest water, and traceability topics.
2.75 NYSDEC CEU's in categories 10, 1a, 22, and 23 available.
