PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND
Kabatina thujae, a new cypress disease in New Zealand
NEW DISEASE OF CYPRESSES FOUND IN TIMARU
From Forest Health News 101, October 2000
During a routine hazard site assessment (September 2000) Vigil Forest Health Adviser Paul Bradbury collected samples of branches with leaf tip dieback from a pair of large Thuja plicata in Timaru. Paul has been inspecting these trees for some years and reports that until this visit there has been no sign of this particular form of foliage death. The fungus Kabatina thujae was identified on the dying tissue and it is the first time it has been recorded in New Zealand. Kabatina thujae is known in both Europe and North America where it can cause a leaf tip death of a range of hosts in the genera Cupressus, Chamaecyparis, Thuja and Juniperus . Susceptible species include several of those cypresses commonly grown in plantations and shelter belts in New Zealand such as C. lawsoniana, C. sempervirens and C. arizonica .
The severity of the dieback varies with both host and location. Considerable damage to Chamaecyparis nootkatensis seedlings occurred in nurseries in British Columbia in 1969, but many other reports from both sides of the Atlantic indicate fairly minor injury to the relevant host. Inoculation tests in Italy showed that Pinus radiata, P. halepensis and P. pinea were slightly susceptible, but there are no records of natural infection of pine hosts. A closely related species of Kabatina, K. juniperi , can cause similar dieback of C. macrocarpa and Juniperus spp. Kabatina juniperi is not known in New Zealand.
(Margaret Dick, Forest Research & Paul Bradbury, Vigil, Christchurch)
