Susceptibility of pine plantations to attack by the pine shoot beetle (Tomicus piniperda L.) in southern Ontario

Tomicus piniperda (L.) (Coleoptera: Scolytidae), was discovered in Ohio in 1992 and spread throughout southern Ontario, Quebec, and the United States. The objectives of this study were to (i) determine the relationships between tree and site characteristics and the number of stem and shoot attacks by T. piniperda in southern Ontario; and (ii) determine if T. piniperda is an aggressive beetle in southern Ontario. Forty-three sites of varying pine species compositions were surveyed across southern Ontario. An abundance of dead and low-vigour pine trees increased susceptibility of sites to attacks by T. piniperda . Significant negative relationships were detected between the number of attacks and the mean height, age, dbh, basal area, canopy cover, duff depth, and radial growth increments of the sites. Pure red pine sites had significantly fewer attacks than sites of pure scots pine and mixed jack pine, which was attributed to differences in tree vigour, and management.