Lodgepole terminal weevil

  • Latin name: Pissodes terminalis (Hopping)
  • French name: Charançon du pin tordu
  • Order: Coleoptera
  • Family: Curculionidae
Description

Distribution

British Columbia, Yukon

This weevil is found throughout much of western North America from Manitoba to British Columbia and from the Northwest Territories to Colorado and California. In British Columbia, it is most common in interior regions south of 560 latitude.

Micro-habitat(s)

Annual shoot, Terminal shoot

Damage, symptoms and biology

The lodgepole terminal weevil, Pissodes terminalis Hopping, feeds in the current year’s terminal growth causing dieback, height growth loss and consequent deformity in the main stem.

The lodgepole terminal weevil attacks and kills the current year’s terminal growth on immature trees 2 to 7 m high. Some preference is shown for vigorous trees in low-density stands. Usually a single branch in the whorl immediately below the attacked leader assumes apical dominance, producing a crook in the stem; infrequently, two or more laterals compete for dominance, resulting in a forked or candelebra-shaped crown. In heavily infested plantations, repeated attacks may result in branched or crooked stems and reduced vertical growth. This species is generally of minor importance.

Deformities result in a reduction of merchantable volume through lost height growth and cause some degradation of lumber due to grain aberrations at the site of the crook (Maher 1979). Careful examination of the leaders for feeding and oviposition punctures can provide early evidence of attack. Weevil damage is often indicated by a gradual fading and twisting of the leaders, which turn red by the following spring. Crooks and forks in the stem may indicate previous attacks.

Egg: Sub-globose, 0.5 by 0.8 mm, translucent white.

Larva: Creamy white with tan head capsule; it lacks developed legs and is about 10 mm long when mature.

Pupa: White, about the same size and form as the adult, bearing a prominent snout.

Adult: 5-7 mm long, cylindrical with a posteriorly tapered body and a prominent elongate proboscis, mottled reddish brown with a more or less continuous band of white and yellow scales near the vertex of the elytral declivity.

The lodgepole terminal weevil has one generation per year. Adults emerge in late spring or early summer and complete a period of maturation feeding on developing terminal growth before mating. The females then excavate oviposition punctures in each of which a single egg is usually placed. These punctures, located on the new terminal growth, are similar to feeding punctures but are sealed with a brown exudate. The eggs hatch in about 2 weeks, and the young larvae begin to tunnel randomly in the phloem and cortex without breaking through the bark. By the second instar, the larvae begin mining upwards in a spiral fashion completely girdling the terminal shoot. During the third and fourth instars, the larvae migrate to the pith where they complete their development. Elliptical pupal chambers enclosed in wood particles are constructed in the pith and may be located throughout the length of the terminal shoot. Usually only one or two larvae survive to maturity in each leader, and in many leaders all the larvae die before completing development. In British Columbia, pupation occurs in fall or spring. Most weevils overwinter as larvae but they may overwinter as pupae or adults.

Other information

The white pine weevil, Pissodes strobi (Peck), may also attack and kill the leader on lodgepole pine, but damage differs from that of P. terminalis as oviposition and larval feeding occurs in the previous year’s growth, killing it and the current year’s terminal growth.

Research Efforts: Past and present work focuses on understanding genetic variation, phenology, associated fungi, natural enemies, and impact.

Canadian Forest Service Publications

Lodgepole terminal weevil

Diet and feeding behaviour

  • Phloeophagous : Feeds on phloem.
    • Endophagous: Feeds within an animal or plant host.
  • Xylophagous : Feeds on woody tissues (wood).
    • Endophagous: Feeds within an animal or plant host.
Information on host(s)

Host plants include immature lodgepole pine, Pinus contorta Dougl., and jack pine, Pinus banksiana Lamb

Main host(s)

Lodgepole pine

Secondary host(s)

Eastern white pine, Engelmann spruce, jack pine, limber pine, ponderosa pine, shore pine, Sitka spruce, western hemlock, western white pine, white spruce, white spruce, whitebark pine

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