Pest profile

White Pine Weevil

Pissodes strobi · Coleoptera: Curculionidae[2]

White pine weevil kills the new terminal growth of spruce, which wilts into a shepherd's crook and then dies.[1]

White pine weevil, a mottled brown snout beetle with pale patches, on a branch
White pine weevil, a mottled brown snout beetle with pale patches, on a branch. (c) Will Linnard, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Wilted leaders curl into a shepherd's crook, and needles pale before dying and dropping.[1]
  • Pupae form in distinctive chip cocoons of stringy wood, and new adults leave holes slightly larger than a pencil lead.[1]

Look-alikes

Look-alikeHow to tell them apart
Lodgepole pine terminal weevilA close relative, Pissodes terminalis, causes similar damage on lodgepole pine.[1]

Where it lives

In Colorado injury is almost entirely in higher-elevation areas and foothills, though it reaches Colorado Springs.[1]

US map: public records from 21 states since 1990 (GBIF).

Biology and life cycle

Adults overwinter in litter near infested trees, then lay eggs in pits just below the new terminal bud in spring.[1]

Legless grubs feed under the bark and tunnel downward, girdling the leader; one generation a year.[1]

Damage and signs

  • Trees end up stunted and bushy, with several competing leaders.[1]

Health risk

It feeds on plants; CSU Extension mentions no risk to people.[1]

Control

Sanitation

Prune out wilting terminals before adults emerge, cutting only the infested part, and remove the prunings from the site.[1]

Traps and physical control

Train a single new leader and pinch competing side shoots to restore the tree's form.[1]

Pesticides

Spring sprays on the terminal target adults before egg laying; fall soil applications of imidacloprid can also prevent injury.[1]

Common questions

Why is the top of my spruce bent over like a cane?
A wilted shepherd's crook leader is the classic sign of white pine weevil.[1]
When should I prune infested spruce tops?
In late spring or early summer, after wilting shows but before exit holes appear.[1]

Sources

  1. Colorado State University Extension, “White Pine Weevil.” extension.colostate.edu/resource/white-pine-weevil/ (accessed 2026-10-06)
  2. iNaturalist, “Pissodes strobi taxon page (order and family).” www.inaturalist.org/taxa/208537 (accessed 2026-10-06)

Updated 2026-10-14. Built from sourced records. Spot an error? Tell us.