OLYMPIA — Bugs hop from leaf to leaf nibbling and spitting Xylella fastidiosa, a plant-scorching bacterium that bedevils Europe.
Across the globe, the Washington State Department of Agriculture’s Cindy Cooper will lead a far-reaching probe to show Europeans that the pathogen doesn’t live in her state.
At stake is the export to Europe of thousands of blueberry, grapevine, raspberry and other fruit plants cultivated in Washington nurseries.
Because of X. fastidiosa, the European Union bars 179 species of plants from entering its 28-nation market. Washington wasn’t singled out. The ban goes for anyplace that can’t say it’s free of X. fastidiosa.
To say that, WSDA will have to check thousands of plants this summer in nurseries and on the landscape. Plants that look suspicious will be tested in a laboratory.
The USDA has granted WSDA $217,000 to help pay for the search. If everything goes right, Europe and Washington nurseries will resume the trade by Thanksgiving.
It’s an example of the work done by WSDA’s plant services program, which Cooper manages. Fending off plant diseases is a constant battle. “With plant movement, with fruit movement, you have pest movement,” Cooper said.
Cooper, 56, has worked for WSDA for 17 years. She started as a plant inspector and worked her way up, becoming the program manager about two years ago. She’s on the board of the National Clean Plant Network, an association overseen by USDA dedicated to keeping the country’s planting stock pathogen-free.
Cooper earned a degree in horticulture from Washington State University and owned a nursery before becoming a state employee. She gardens, of course. “A new nursery is like a candy store to me,” she said. “I knew from the age of 10 that I wanted to grow plants.”
Her program includes 10 plant inspectors. In a year, they do about 700 inspections at nurseries. There are more than 5,000 nurseries. Cooper said they have to pick their spots. High-volume garden centers, big-box retailers and nurseries that export plants get the most attention.
‘Ebola of olives’
The unexpected happens. Again, X. fastidiosa is an example.
The disease is known in the Americas. A strain commonly referred to Pierce’s disease has long bothered California grapevines.
X. fastidiosa crossed overseas and was found in Italian olive groves in 2013. To stem the disease, a European court ordered Italian olive farmers to destroy thousands of trees. X. fastidiosa still spread to France and then Spain. A Spanish newspaper coined a phrase constantly used since in press reports, calling the disease the “Ebola of olive trees.”
In May of 2015, the EU barred the importation of the large number of plants vulnerable to X. fastidiosa and set rules for regaining market access.
To complicate matters, the disease was found the following October in pear plant material at the USDA germplasm repository in Corvallis, Ore. The only other time the disease had ever been documented in pear trees was in Taiwan in the 1990s. The disease had never been found in the Northwest.
“It was a huge surprise to everyone,” Cooper said.
The glass-winged sharpshooter spreads the disease in California, but Northwest winters are too cold for that bug. The blue-green sharpshooter and common spittlebug are under suspicion for carrying the pathogen in the Northwest.
Infected plant material from Corvallis had gone to a nursery in Hood River County. From there, material went out, including to about 40 residences in Washington.
Oregon responded by surveying for X. fastidiosa. By February 2016, the USDA told the EU that 12 Oregon counties were free of the disease.
The following summer, two Washington nurseries funded a WSDA search for the disease in Thurston and Grays Harbor counties. In November, the USDA told EU those two counties were clean.
This summer, WSDA will extend the search to Benton, Chelan, Clallam, Clark, Franklin, Grant, King, Lewis, Snohomish, Whatcom, Whitman, Yakima and Skagit counties. The counties were selected because they have nurseries that export plants or are fruit-growing areas. Besides proving to Europe that the state does not have X. fastidiosa, WSDA wants to make sure the disease isn’t in a position to threaten Washington crops, particularly grapevines.
WSDA will follow up and search again in the summers of 2018 and 2019 to make sure there is no X. fastidiosa.
And if it is found?
“We would have to meet with all stakeholders and understand the risk to trade brought up by that revelation,” Cooper said.
Position: Washington State Department of Agriculture plant services program manager
Education: Bachelor’s degree in horticulture, Washington State University
Memorable: The discovery in 2003 of sudden oak death, a tree disease, leading to the destruction of thousands of nursery plants. “It was terrible,” Cooper said. “We had to dig holes, bury plants and burn them.”