Evaluation of Fungicides for Hop Downy Mildew, Hubbard, Oregon, 2025

Hop downy mildew, caused by Pseudoperonospora humuli, is a widespread and damaging disease of hop in many production regions worldwide. In the western United States, one of the important aspects of the disease is shoot infection in spring and early summer. This report summarizes the efficacy of synthetic and biological fungicides in the suppression of hop shoots with systemic downy mildew in Humulus lupulus ‘Nugget’ in a trial conducted near Hubbard, OR, in 2025. Findings from this trial will help inform management of the disease and support future analyses that can mitigate crop damage and minimize use of ineffective or unnecessary pesticide applications.