Project: 2004-04. Report - Risk assessment of European pests of Pinus radiata (2004–04)

Date: 2006 Author: Ensis Publication: Report Project reference: 2004-04 Report is available online Download report

Executive summary:

Reports from southern Europe indicate that Pinus radiata planted there is highly susceptible to attack by several European pests of pines. In particular, repeated outbreaks of the pine processionary moth (Thaumetopoea pityocampa) have caused much damage in pine plantations in Spain and adjacent countries. Anecdotal reports suggest that P. radiata is more affected by insect pests than the native pines,
although there is limited experimental evidence. We undertook a study that combined (1) a review of published and unpublished information on pests affecting P. radiata in
Europe and (2) experimental work on insect pests of P. radiata in plantation forests in the Spanish Basque Country and in south–west France. The objectives were:

• to summarise the key characteristics of European pests of Pinus radiata and the damage they can cause,
• to compare the susceptibility of Pinus radiata and other exotic and native pines to these pests,
• and to discuss the implications for forest biosecurity in New Zealand.

Based on our observations, the principal insect pests that affect P. radiata where it is planted in southern Europe are (in decreasing order) the pine processionary moth, the bark beetle Ips sexdentatus, and the pine stem borer Dioryctria sylvestrella. Numerous other bark beetles, moths, and other insects can also cause some damage. Damage from the pine processionary moth was highly noticeable in many P. radiata stands, and a comparison of attack and damage in several mixed stands revealed that P. radiata is indeed significantly more attacked and damaged than the common native pines in the area, Pinus pinaster (maritime pine) and Pinus nigra
(Corsican pine). No such preference for P. radiata was observed for Ips sexdentatus in our comparison between eight pine species, but observations in the field indicated that Ips sexdentatus can attack and kill an entire stand of trees of P. radiata that were previously stressed by a hail storm. Both these insects could become major pests if they invaded New Zealand. However, the pine processionary moth is a comparatively poor disperser and Ips sexdentatus, while it is often transported with wood packaging materials, appears to be less invasive than other bark beetles. Nevertheless,
incursions and establishments of many related species have occurred in New Zealand and elsewhere. We make a number of recommendations to improve border biosecurity.

Report is available online