On the Trail of a Killer

Investigators from the Oregon Department of Agriculture descended upon a Scappoose nursery this month, in hopes of containing an outbreak of sudden oak death--a blight that could spell disaster for the state's horticulture business.

State officials ordered an emergency quarantine of Columbia County nurseries and compost producers earlier this month to prevent the disease from spreading.

Among Oregon's thousands of nurserymen and -women, the quarantine fertilized fears of pruned profits and wilted wages--with ample reason. Clackamas, Marion, Washington, Yamhill and Multnomah counties are the state's top producers of greenhouse and nursery products, with gross sales in excess of $596 million a year, the bulk of which are exports.

Unfortunately for Scappoose-based Means Nursery, this year's harvest is a bumper crop of hassle. According to Means, state officials visited the nursery "to identify specific blocks of plants...and advise the nursery on the proper procedures to destroy the infected plant material."

The disease is caused by a funguslike organism that attacks the bark of trees and shrubs, including Douglas firs, rhododendrons, huckleberries and Coast redwoods. The pathogen prefers damp conditions between 50 and 65 degrees Fahrenheit and attacks its host branch by branch, leaving it vulnerable to insects and rot.

At Means, the outbreak is thought to have stemmed from a tainted blend of compost and bark used as potting mix. "Our suspicion is that we're looking at a secondary infection," explains Dan Hilburn, administrator of the ODA Plant Division.

While Oregon researchers are still puzzling over the source of the outbreak, they do know that diseased rhododendrons traced to Means Nursery have been discovered in Maryland.

At the moment, the only way to stop the disease is to destroy the infected plants; however, scientists in Virginia and California announced two weeks ago that they have mapped the genetic codes of the fungus that causes the disease, which they hope will lead to new treatment methods.

Repeated attempts by WW to tour Means facilities and view such procedures met with no success, and Means refused to answer questions about plant destruction or compost supply.

In an industry that relies so heavily on exports, the mere perception that sudden oak death could be widespread in Oregon could have a devastating effect. "This is as serious as it gets," says Hilburn.

WWeek 2015