Farm Forestry New Zealand
PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND
Pine Pitch canker intercepted in New Zealand
From Forest Health News 137, February 2004.
Early in 2003 Douglas fir (Pseudotsuga menziesii) scions were imported into the South Island from California and Oregon, from locations some distance from known pitch canker infection sites. The scions were grafted onto New Zealand-grown root stock and held for observation in a Ministry of Agriculture and Forestry supervised quarantine facility. In line with import requirements, random samples were collected and examined for pests at intervals during the quarantine period. While testing some of these samples in November 2003, Forest Research pathologists discovered Fusarium circinatum, the fungus that causes pitch canker (FHNews 135:1). The identification of this pathogen was based on both cultural characteristics and a molecular technique developed at Forest Research, and was later independently confirmed by researchers in California.
Subsequently, forest pathologists in the United States surveyed the stand from which the scions were collected and have now confirmed the presence of F. circinatum in symptomless Douglas fir trees on the site. This raises a number of important questions about the ecology, host interactions, and distribution of the fungus. How widespread is F. circinatum? Can we be sure that an exporting area is truly free of F. circinatum, now that Douglas fir appears able to act as a symptomless host? Are there other plant species capable of acting as symptomless hosts of F. circinatum?
In response to the find, the New Zealand Ministry of Agriculture and Forestry has restricted the importation of Douglas fir material from the USA to seed, which must still be grown in high-security quarantine facilities until declared disease free.
(Margaret Dick, Forest Research)
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