Guess The Pest! Week 10 Answer: Copper Fungicide

David Owens, Extension Entomologist,

Congratulations to Leah Fronk for correctly identifying certain fungicides as the culprit for the apple russeting. Leah will be entered for an end-of-year drawing for a jar of local honey and a scouting kit.

This from Dr. Gordon Johnson:
On apples, copper applied between half-inch green and bloom usually causes fruit russeting. This is variety and copper formulation dependent. Avoid copper fungicides during bloom and choose varieties that are less prone to russeting when possible.


apple russeting (brown dry areas on a green apple)