Late Season Rescue Thinning with Ethephon
Ethrel for Rescue Thinning in Eastern New York - Dan Donahue
Our colleagues in Massachusetts and New Jersey have conducted extensive research over the years on the use of Ethephon as a "rescue thinner" when fruits reach the 20-25 mm stage. I've posted a fact sheet and a power point presentation on the ENYCHP website that offers excellent guidance on the use of this material as a thinner. With this seasons bumper fruit set, coupled with weak thinner performance, ethephon should be considered as an option, but please follow the links below and study the information provided before acting. Ethephon can be a strong thinner, very sensitive to temperatures in the several days following application, capable of defruiting the tree in some circumstances. Thank you to Win and Wes for giving ENYCHP permission to post this information.
Rescue Thinning with Ethephon PowerPoint/pdf Talk (pdf; 4398KB)
- Author: Win Cowgill presented at the Connecticut Pomological Society
Fact sheet- F-129R UMASS-Rutgers- Late Season Rescue Thinning with Ethephon (pdf; 682KB)
- Authors: Wesley Autio, Win Cowgill

Upcoming Events
Rulfs Orchard Vegetable and Berry Field Meeting
August 4, 2026
Peru, NY
Join CCE vegetable specialists Elisabeth Hodgdon and Chuck Bornt for a vegetable and berry field meeting at Rulfs Orchard, in Peru, NY. We'll tour the farm's fields and talk about integrated pest management of sweet corn and cucurbit crops. Then, we'll view a drone demonstration and discuss new technologies for pesticide application and spotted wing drosophila management in berries. Light refreshments will be provided. A rain date will be announced if adverse weather is predicted.
Field Day at Philia Farm
August 6, 2026
Johnstown, NY
Visit organic seed production trials and tour the farm to see small-scale production systems at work, including tarping, cover cropping, and the use of assorted mulches and covers to modify the growing environment.
Capital Region Orchard Twilight Meeting
August 11, 2026
Rexford, NY
Join the ENYCHP and Cornell scientists on August 11 for the Capital Region Orchard Twilight meeting in Saratoga! We will be touring Bowman Orchards and reviewing seasonal recommendations for pests and diseases for apples, plums, and berries, as well discussing crop insurance.
NYSDEC Pesticide Applicator Recertification Credits: 1.25 in categories 22, 1A, & 10. Refreshments will be provided.
Free to attend, however we do ask that you register ahead so we know how many people to expect.
