Hop Growers Launch Spore War Fire Will Be Used To Control Spread Of Powdery Mildew

Yakima Valley hop growers are fighting fungus with fire.

Roots from an estimated 6,000 acres of the crop will likely be torched this spring or summer as farmers battle a tough hop-killing fungus known as powdery mildew.

And the destruction could be much worse than initial projections, said Ann George, administrator for the Washington Hop Commission.

“We have never gone into a spring with this disease. We don’t know what to expect. We have to plan for a worst-case scenario and try to protect our crop,” George said.

Researchers have no idea how well the mildew survived the winter, said Bob Klein, plant pathologist at Washington State University’s research station at Prosser.

But even if mildew survives on only 1 percent of the roots, “in no time at all you are going to have 100 percent infected plants,” Klein said. “The (mildew spores) blow around with great ease.”

In an attempt to help hop growers, Yakima and Benton county clean-air agencies announced Monday they will allow farmers to burn hop plants without getting permits or paying fees. Farmers still must notify clean-air agencies about their fires and they cannot burn during burn bans.

Altogether, the exemption will save hop growers about $9,000 in permit fees at $1.50 per acre.

“It’s a major step for us and very important that the growers are able to burn their trash,” said Sean Gree of Hop Growers of America. “The (mildew) spores live on live plants. Now we have a way of destroying that plant material.”

Washington’s $100 million hop industry produces about three-quarters of the hops grown in the United States. Oregon and Idaho produce the rest. Hops are used primarily in brewing beer.

Burning is one of only a few tools available to hop farmers right now, Klein said. Sulfur is the only approved mildew treatment, though emergency applications are in for three pesticides and Klein expects them to get approved soon.

“It does appear that burning is the best method right now,” said Pruitt, who got his first call under the new rule Friday.