Despite the implementation of certification programs and best management protocols, the re-infestation rate of Phytophthora ramorum is of concern to industry and government officials in Canada and the United States. Post eradication surveys show that several sites found infected with P. ramorum in 2004, and subsequently eradicated in accordance with the provisions of the Infested Nursery Protocol, report positive plants again this year.
Within Canada, four positive plants were found at two retail garden centres this year, one wholesale nursery and a landscape site. All of these positives were discovered as part of the Canadian Food Inspection Agency’s post-eradication surveys in B.C. None of these positive findings will result in trace forward activity to Ontario. National summer surveys are now underway across Canada. Actual numbers of nurseries surveyed or samples collected and tested are not available from CFIA. However, industry is updated on positive findings through weekly Sudden Oak Death Task Force conference calls.
Earlier this spring, Landscape Ontario and Ontario Ministry of Agriculture and Food shared the cost to send two OMAF staff representatives to a P. ramorum workshop hosted by the California Oak Mortality Task Force (COMTF) and to visit other nursery sites and research projects in California, Oregon, Washington and B.C. As a result of the findings of nursery extension specialist Jennifer Llewellyn and plant pathologist Mike Celetti, OMAF has submitted a letter to CFIA, requesting that CFIA take over the audit of the industry’s voluntary P. ramorum certification program, until industry can develop and implement its own CFIA-approved verification process. Especially in view of the rate of re-infection, OMAF staff has expressed concern that CFIA is not doing enough to stop the spread of P. ramorum. To date, there has been no official response from CFIA in this regard.
CFIA and USDA officials met in Quebec recently as part of their ongoing, harmonized development of the various P. ramorum-infested place protocols (including nursery, retail garden centre and landscape). Considerable time was spent analyzing and addressing potential gaps in the infested nursery protocol.
Revisions will be made, and once released, the updated version will be posted to the CNLA web site: www.canadanursery.com, as will the new version of the retail garden centre protocol.
Grower research initiatives
In response to funding received through the Canada-Ontario Research and Development Program (CORD IV), the Landscape Ontario Growers’ Group met recently to discuss industry’s research priorities. An application for a three-year risk management project has already been approved. Other projects considered to be a high priority include chlorination of recycled water that has potentially been infested with P. ramorum, improved irrigation practices as part of the industry’s on-going nutrient management mandate and control of tar spot in the landscape. Ongoing results of these research projects will be published in Horticulture Review as they become available.
