Pales weevil

Distribution

Canada

Common throughout the range of conifers, especially pine, in Ontario.

Damage, symptoms and biology

This weevil can be the most serious insect pest of pine regeneration in recently logged pine areas. It has caused serious damage in newly planted pine plantations. Mortality rates of 90% have been recorded. Adults are attracted by fresh pine resin to newly logged areas and feed after dark on the tender bark at the base of newly planted seedlings. Heavy feeding soon girdles and kills the seedling.

It overwinters either as an adult in the duff layer or as a larva under the bark in the roots of the host tree. Overwintering adults emerge the following spring in May or June. Overwintering larvae construct cells in the outer sapwood, hibernate, then pupate and emerge the following June or July. Some larvae will pupate in the fall and emerge as adults in the winter.

In the adult stage, this root collar weevil is reddish-brown to black, with yellowish-white scaly patches on the head and irregular markings on the elytra. The adults that overwinter and emerge in the spring feed for a short time on the tender bark of twigs or seedlings. They then mate and the female lays her eggs below the root collar of a freshly cut pine stump or on the stump of a stressed, dying tree.

The grubs feed downward along the roots on the inner bark until late fall. In southern Ontario the larvae feed under the bark of the root collar, not the roots. The newly emerged (September or October) adults feed on pine bark, twigs or needles until they hibernate in the duff layer beneath the pine trees. There is usually one generation per year, but some adults may live for 2 years.

Other information

Damage can be kept to a minium by silvicultural practices. Cutover areas should not be planted for two years or direct seeded for 1 year. In Christmas tree operations, stump removal the following spring is strongly recommended.