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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Publications at this Location » Publication #430174
Research Project: Development of Superior Hops and Resilient Hop Production Systems

Location: Forage Seed and Cereal Research Unit

Title: Evaluation of fungicides for hop powdery mildew, study 2, Granger, Washington, 2025

Author
item MASSIE, STEPHEN - Washington Hop Commission
item RICHARDSON, BRIANA - Oregon State University
item Gent, David

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2026
Publication Date: 3/19/2026
Citation: Massie, S.T., Richardson, B.J., Gent, D.H. 2026. Evaluation of fungicides for hop powdery mildew, study 2, Granger, Washington, 2025. Plant Health Progress. 27(2):347. https://doi.org/10.1094/PHP-11-25-0264-PDMR.
DOI: https://doi.org/10.1094/PHP-11-25-0264-PDMR

Interpretive Summary: This study was part of ongoing efforts to improve practical management of the disease hop powdery mildew. We evaluated non-synthetic and organic-approved alternatives for their ability to complement or substitute current industry standard fungicides. The results point out that under the low disease pressure conditions in this, it might be possible to control the leaf phase of powdery mildew using non-synthetic alternatives.

Technical Abstract: Powdery mildew of hop is caused by Podosphaera macularis. This disease affects all green tissue of the hop plant, forming the characteristic signs of white colonies that bear mycelia and conidia and which lead to browning, shatter, and yield damage when infection occurs on the inflorescence. This report communicates efficacy data of various fungicides against powdery mildew. This trial was conducted on the hop (Humulus lupulus) cultivar ‘Galena’ during the spring and summer of 2025, near Granger, Washington. Results from this trial will help producers develop more effective management approaches for the disease.