Cooperative Extension Service Communications and Technology Department 3354 1000 E. University Ave. Laramie, WY 82071 (307) 766-2540 • fax (307) 766-3998 • www.uwyo.edu

 

For Immediate Release

 

Contact: Robert Waggener, Editor

Phone: (307) 766-3571

E-mail: robertw@uwyo.edu

 

Date: May 10, 2006

 

No sudden oak death detected in Wyoming plant samples

            Sometimes no news is good news in the world of University of Wyoming Professor Gary Franc.

            This was the case when Franc’s laboratory last fall completed its second consecutive year of testing in Wyoming for the presence of the fungus-like organism Phytophthora ramorum, which causes sudden oak death. His report was recently completed and sent to the U.S. Department of Agriculture (USDA).

            “No news is good news. We didn’t detect the pathogen in any of the plant materials we tested that were brought into Wyoming, and we hope this continues,” said Franc, a plant pathology specialist in the College of Agriculture’s Department of Plant Sciences.

             “There is a national survey protocol that requires all states, including Wyoming, to test certain horticultural plant materials brought into the state. We have been doing this testing quietly behind the scenes for two years now, and so far we have failed to detect the pathogen, which is very good news for Wyoming,” Franc said.

            Phytophthora ramorum was first recovered from diseased plants in Germany and the Netherlands in 1993 and, since its discovery in California two years later, thousands of oak trees have died along the West Coast, and numerous other trees are in declining health, he said.

            In 2004, several large nurseries along the West Coast were exposed to the sudden oak death organism, and some infected plant material may have been inadvertently shipped to customers throughout the United States.

            “The national survey was initiated in response to this threat, and tests revealed that infected plant material was traced to a number of other states, mostly in the South and Southeast,” he noted. “If infested material is identified, the protocol is to destroy that material.”

            The USDA Animal and Plant Health Inspection Service’s Plant Protection and Quarantine (APHIS PPQ) started working with states across the country.

            In Wyoming, the APHIS PPQ, in conjunction with the Wyoming Department of Agriculture, selected 43 greenhouses and nurseries in 18 Wyoming counties to survey last year, the second year of the testing.

            The UW Cooperative Extension Service plant pathology program, which is under Franc’s direction, offered training to inspectors on disease recognition and sample collection, and his laboratory also analyzed plant samples to detect if the pathogen was present.

            Franc said 67 samples from the 43 sites were tested, and all were negative for the presence of Phytophthora. The samples were collected last July and August, and Franc earlier this year completed his report to APHIS PPQ. Assisting in the testing was Shaleas Harrison of Powell, a health sciences and molecular biology undergraduate student who works in the laboratory.

            Franc said Wyoming’s testing exceeded federal requirements in both 2004 and 2005.

            “We’ve consistently over-sampled because we feel it’s better to be on the safe side,” he said. “We do want to get this message out to the state because the testing is designed to protect the horticulture industry from the inadvertent spread of this pathogen in Wyoming and other states.”

            Franc added, “We don’t know the potential of this organism to become established in our wild plant population in Wyoming, and we don’t want to find out.”

            The pathogen is favored by cool, moist and humid environments, like those found along the West Coast.

            “One of the reasons we don’t know the potential for its spread here is because we don’t have an ideal environment for the pathogen. This is a new disease, and we’re simply not sure of what it could or would do in Wyoming,” Franc said.

            Certain native California oak and at least 40 other native and horticultural species are hosts for the fungus. Among them are Douglas fir, lilac and viburnum – three common plants in Wyoming.

            Asked what nurseries can do to help prevent the spread of sudden oak death, Franc responded, “Purchase high-quality transplant materials from reputable greenhouses and suppliers.”

            What about homeowners wishing to plant viburnum and lilacs in their yards? “The same holds true. Purchase plants from reputable greenhouses and nurseries. Transplanting materials, especially from other states, would put you at risk.”

            In oak trees along the West Coast, Franc said, “The pathogen infects the tree bark. As the bark is destroyed, it can girdle the stem or the trunk and can cause tree death. It appears plants in the understory of oaks also become infected and can provide a fairly constant supply of inoculum from which the organism spreads.”

            Franc is preparing for the third year of testing, which will continue in the state as long as it’s required by APHIS PPQ.

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