Northern pine weevil

French common name: Charançon du tronc des pins
Scientific name: Pissodes nemorensis Germar
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Curculionidae
Partial list of synonyms:
- Pissodes approximatus Hopk.

Distribution

Alberta
Manitoba
New Brunswick
Nova Scotia
Ontario
Prince Edward Island
Quebec

Damage, symptoms and biology

Damage by the Northern pine weevil is caused primarily the larvae, which feed by tunnelling under the bark. The insect attacks the branches, trunk and collar of both young plantation trees and larger trees, especially weakened, stressed or dying trees. The insect also attacks the trunks and stumps of freshly cut trees. The resulting network of tunnels disrupts the flow of sap and, if the trunk and collar are severely attacked, rapid dieback occurs and the tree dies during the same season.

Evidence of the presence Northern pine weevil is the swelling of the bark, which raises easily at infested sites. Under the bark, damage is easily recognized by the presence of chambers lined with wood shavings, or “chip cocoons”, which enclose a larva or pupa.

The adult overwinters in the litter near infested trees or in bark crevices. In early May, the adult weevils emerge and feed for several weeks on branches or trunks, puncturing the tender bark of young trees with their proboscis. The female deposits her eggs in the feeding holes.

The cycle lasts two years and generations overlap. The insect overwinters as larvae, pupae or adults. Insects overwintering in the larval or pupal stage emerge in June or July and overwinter as adults.

Other information

Native to North America, the Northern pine weevil occurs primarily in pine plantations and intensively managed stands. It causes limited damage in natural forests, but in plantations, the presence of large numbers of stumps favours the proliferation of the insect.

In Canada, the insect occurs primarily in Scots pine Christmas tree plantations. In Quebec, it is occasionally reported in red pine plantations or Eastern white pine hybridization parks.

Adult Northern pine weevils and adult white pine weevils, Pissodes strobi (Peck), are very similar in appearance, but their damage cannot be confused because white pine weevils attack exclusively the terminal leaders.

As a silvicultural practice in plantations, it is advisable to cut down severely affected trees, remove the stumps and burn all cutting wastes in order to eliminate environments that favour the breeding of the insect.