Infections of sudden oak death were found in 10 plants shipped from California to two Jackson County, Ore. retail outlets. The discovery follows an outbreak of the disease at a Clackamas County nursery in Oregon last month and confirmation Thursday that sudden oak death was detected for the first time in Washington state.
Green industry professionals are calling for greater vigilance in the industry in terms of heading off such outbreaks, particularly regarding potentially infected plant material from Europe.
"There's definitely a growing concern about what measures need to be put in place," said Craig Regelbrugge, senior director of government relations, American Nursery & Landscape Association, Washington, D.C. "But there's this wide spectrum of opinion: Is this the perfect storm of climatic conditions that will keep it confined mainly to California? Or is it the next chestnut blight?"
Oregon agriculture officials said the infected Jackson County plants were discovered after tracing shipments from four California nurseries where the pathogen was found. There is no evidence to suggest a connection with the Clackamas County outbreak in May where a Furnery’s nursery was quarantined. There are ongoing investigations at Furney’s to trace the source of the infected plants as well as shipments to other nursery and landscaping companies in Oregon and Washington.
The Oregon Department of Agriculture reports that thousands of infected plants have been destroyed and any infected plants found in tracing efforts will also be disposed of. Washington officials said Thursday that they confirmed the disease was present in four rhododendrons at a Furney's Nursery in south King County. They are awaiting test results from the other five locations.
Sudden oak death, which has killed more than 100,000 trees and plants in 12 coastal California counties, attacks certain oak varieties, as well as rhododendrons, huckleberry, Viburnum and honeysuckle. Some plants, such as redwoods and Douglas firs, act as hosts but are not significantly damaged by the disease. There is no known cure for the fungus Phytophthora ramorum, which spreads through infected wood, soil and rainwater, and possibly through airborne spores in moist conditions.
Oregon researchers last week completed tests showing that the strain found in Clackamas County is of European origin, distinct from what is killing oaks in California. John Aguirre, executive director of the Oregon Association of Nurserymen, said the new finding in Jackson County is not nearly as troubling as the Furney's outbreak.
"This points out that we've got exposure from California," he said. "But it's very small, very manageable."
Nurseries are the top agricultural segment in Oregon, with $714 million in annual sales and disease outbreaks can certainly have an economic impact on the industry.
"The economic implications are huge for the state," said Hilburn, administrator of the state Agriculture Department's plant division. "If a market closes down, it doesn't matter what response you're capable of because you just lost the market."
Portions of this story originally reported by Alex Pulaski, The Oregonian, Portland, Ore.