Pest Alert: Phytophthora ramorum (Sudden Oak Death) update for 2006 (February 8, 2007)

In Massachusetts 23 nurseries were included in the 2006 Phytophthora ramorum survey conducted by the MA Department of Agricultural Resources in cooperation with the USDA, APHIS Cooperative Agricultural Pest Survey. The UMass Plant Disease Diagnostic Lab tested 100 samples from these sites by ELISA and culturing, and none were positive for P. ramorum. Forty six states participated in the national Nursery Survey while Alaska, Iowa, Missouri, and Puerto Rico did not participate. Wisconsin included P. ramorum as part of their regular nursery inspection. In total, 4,843 nurseries were visited and 147,347 samples collected. Sixty two nursery sites in 11 states were confirmed positive (Alabama, California, Connecticut, Florida, Georgia, Indiana, Maine, Mississippi, Oregon, Pennsylvania, and Washington). Two residential sites also had positives.

The United States Forest Service (USFS) has conducted surveys near nurseries and within the forest environment. The Massachusetts Department of Conservation and Recreation worked with USFS to survey nursery perimeters in Massachusetts. As of October 16, 2006, USFS reported the perimeter surveys were conducted at 637 nurseries in 29 states. USFS also reported 366 general forest surveys have been conducted in 29 states, with 922 samples collected. In 2007 the USFS will work with its state cooperators to survey for P.ramorum in waterways.

The damage caused by P.ramorum was first observed in the 1990s in California when large numbers of tanoak, coast live oak, and California black oak were dying off. The cause was not identified until 2002 when researchers compared the Phytophthora isolated from California trees to the new species, Phytophthora ramorum, recently described in European nurseries. P.ramorum has a broad host range and has the potential to infect many plants important to the nursery trade and forest areas. Photos and descriptions of these symptoms and links to further information on sudden oak death are available at: http://www.massnrc.org/pests/pestFAQsheets/suddenoakdeath.html. For the most up-to-date regulatory information and a listed of regulated hosts visit the USDA, APHIS website: http://www.aphis.usda.gov/plant_health/plant_pest_info/pram/index.shtml.

The pest alert is from the Massachusetts Introduced Pests Outreach Project, a collaborative project between the Massachusetts Department of Agricultural Resources and the UMass Extension Agriculture and Landscape Program aimed at preventing the establishment of new pathogens and pests in Massachusetts. Visit the project website (http://www.massnrc.org/pests) for more information on Sudden Oak Death and other emerging pests or to subscribe and unsubscribe for pest alerts.