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Both the U.S. hop industry’s awareness of the critical need for clean planting stock, and the clean plant center at Washington State University, have deep roots that predate the National Clean Plant Network, and through close collaboration have developed tools to help propagators and growers make informed decisions around planting virus-tested hops. Indeed, the outbreak of hop stunt viroid in the Pacific Northwest in the early 2000’s was a driving force in Hops joining NCPN as a founding member.


Given that much of the hop industry replies on direct planting and self-propagation, rather than large-scale nursery production, NCPN-Hops interacts closely with all potential users of virus-tested propagative material across the U.S. Spreading awareness of the benefits of starting with hop cuttings, plantlets, or rhizomes free of harmful pathogens like hop stunt viroid, hop mosaic virus, and apple mosaic viruses, is critical to a successful integrated pest management program, and provides major economic benefits to U.S. hop growers. Below you will find resources ranging from virus identification, clean hop propagation guides, best management practices to help reduce virus transmission, and industry association publications, that should provide valuable information to ensure that U.S hops will "Start clean, Stay clean."



Hop Research Council: 

Idaho Hop Growers Commission: 

Oregon Hop Commission:

State Quarantine Rules

Washington State: 

Oregon State:

Idaho State:

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