White pine weevil
Pissodes strobi
69 host plants
Last updated
White pine weevil larvae tunnel inside the terminal leader of spruce and pine, killing the shoot and causing a characteristic shepherd's crook curve as lateral branches grow upward. You will see small, round exit holes in the bark of damaged leaders in summer, with copious resin bleeding from infested terminals. Affected trees are permanently deformed, with crooked trunks.
Prune off infested leaders by early July, cutting six inches below visible damage. Discard pruning material away from trees or burn it to destroy larvae. Avoid planting susceptible species in harsh, open sites where leaders are weakened. For high-value landscape plants, wrapping leaders with burlap in spring reduces adult weevil feeding.
Quick Reference
White pine weevil First adult activity typically begins around 630 GDD₃₂. As of April 3, 2026, all seven Puget Sound stations have passed this threshold (1070–1180.6 GDD₃₂), so First adult activity is likely underway across the lowlands.
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 3, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,181 | First adult activity | — | — |
| Seattle / UW | 1,171 | First adult activity | — | — |
| Kent / Auburn | 1,111 | First adult activity | — | — |
| Olympia / Tumwater | 1,106 | First adult activity | — | — |
| Bellingham / Whatcom | 1,101 | First adult activity | — | — |
| Tacoma / Puyallup | 1,075 | First adult activity | — | — |
| Sequim / Rain Shadow | 1,070 | First adult activity | — | — |
Source: UMD IPMnet catalog. Sources: UMD: extension.umd.edu; Wisconsin Extension: Wisconsin Extension. About GDD₃₂ →
Cultural Controls
- Prune out damaged terminal and train a new leader to replace it to improve tree's appearance.
- Prune and destroy affected terminals in the summer before adult beetles emerge.
- This will help reduce next year's infestation.