Sequoia pitch moth
Synanthedon sequoiae
57 host plants
Last updated
Clear-winged moths resembling yellow jacket wasps lay eggs on pines, with yellowish larvae bearing reddish-brown heads tunneling into the cambial layer. Distinctive masses of pitch and frass develop at feeding sites, soft and whitish-pink when fresh, hardening and darkening with age; resin masses can reach 1-2 inches in diameter.
Healthy trees are rarely attacked; infestations follow pruning wounds or mechanical damage. Avoid spring and summer pruning when moths are flying. Keep trees vigorous through irrigation and avoid stress. Remove pitch masses to prevent larval development. Prune severely infested branches.
Quick Reference
Sequoia pitch moth Emergence (est.) typically begins around 1778 GDD₃₂. As of April 3, 2026, Puget Sound stations range from 1070 to 1180.6 GDD₃₂, approximately 597 units before the expected threshold.
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 | Pre-season | Emergence (est.) | 597 |
| Seattle / UW | 1,171 | Pre-season | Emergence (est.) | 607 |
| Kent / Auburn | 1,111 | Pre-season | Emergence (est.) | 667 |
| Olympia / Tumwater | 1,106 | Pre-season | Emergence (est.) | 672 |
| Bellingham / Whatcom | 1,101 | Pre-season | Emergence (est.) | 677 |
| Tacoma / Puyallup | 1,075 | Pre-season | Emergence (est.) | 703 |
| Sequim / Rain Shadow | 1,070 | Pre-season | Emergence (est.) | 708 |
Source: Pest GDD Catalog (UMD IPMnet), Added 2026-04-03 About GDD₃₂ →
Cultural Controls
- Prune susceptible trees (pines, Douglas fir) only when egg-laying females are not active (around October to March).
- Avoid mechanical injury to trunks and branches which may provide sites for infestation.
- Remove pitch masses and associated larvae by hand.