Combatting disease in key beer ingredient

By Terri Reddout, WSU Irrigated Agriculture Research and Extension
PROSSER – Informed beer drinkers everywhere are raising a toast to Washington State University, home of a new federal program to fight disease in hops, the ingredient that flavors and preserves America’s favorite brew.
Most sought after hops
Some of the world’s most sought after hops are grown in the Pacific Northwest.
The headquarters for the National Clean Plant Network for Hops (NCPN-Hops) is WSU’s Irrigated Agriculture Research and Extension Center in Prosser. The focus of the program is identifying and eliminating diseases caused by virus-like agents, especially hop stunt disease.
Stunting growth and yield
Hop stunt disease does just what its name implies: it stunts plant growth, resulting in smaller yields and a stunted bottom line.
That has an economic impact on the Pacific Northwest where commercial hop production is concentrated. The U.S. hop industry supplies one-third of the word’s annual crop. More than 80 percent of each year’s harvest is exported to more than 60 countries. Pacific Northwest commercial growers produce an annual farm-gate value exceeding $200 million.
Identifying and halting spread 
“We first spotted hop stunt disease in 2004,” said WSU plant pathologist Ken Eastwell. “By 2005, there was evidence that the disease was being spread when new plants were propagated from hop stunt-infected hops.”
Hops producers needed to know that the hops being planted in their hop yards were not infected with the disease. So they turned to WSU, which also runs virus elimination programs for fruit trees and grapevines.
All the WSU clean plant programs are funded through the U.S. Department of Agriculture’s National Clean Plant Network.
Hop plants undergoing heat therapy
to remove viruses.
The NCPN-Hops’ focus is on identifying and eliminating hop stunt and other yield-robbing viruses. Data gathered from WSU’s hop research plots indicates hop stunt not only reduces yield, but also the alpha and beta acids found in hop cones. These acids are the sought-after flavor components that give beer its refreshing bitterness.
22 virus-free selections
So far the NCPN-Hops program has produced 22 virus-free selections of the most economically important hops. Those plants are being propagated and distributed to eager growers. The program continues to work on cleaning up several other varieties and expects to release at least five selections every year.
Click the following link to learn more information about WSU’s collaborative effort to increase the economic sustainability of specialty crop production in the United State.