Pest profile

Pitch Moths

Synanthedon sequoiae and S. novaroensis (shown: Douglas-fir pitch moth) · Lepidoptera: Sesiidae[2]

Large gummy pitch masses on pine trunks usually mark pitch moth larvae; they rarely kill trees and favor wounded bark.[1]

Douglas-fir pitch moth, a wasp-like clearwing moth with dark body and pale bands, on a pale surface
Douglas-fir pitch moth, a wasp-like clearwing moth with dark body and pale bands, on a pale surface. (c) Doug Macaulay, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Pitch masses start small, soft and reddish brown to pink, then grow, harden and turn gray.[1]
  • A brownish pupal case may stick out after the moth emerges, and old masses can stay for years.[1]
  • Adults are clearwing moths.[1]

Look-alikes

Look-alikeHow to tell them apart
Bark beetle pitch tubesBark beetle pitch tubes are usually under 1/2 inch with a round hole near the center, much smaller than pitch moth masses.[1]

Where it lives

The sequoia pitch moth ranges from California to British Columbia, mostly on Monterey pine in Northern California coastal cities; the Douglas-fir pitch moth ranges from Northern California to Alaska.[1]

US map: public records from 8 states since 1990 (GBIF).

Biology and life cycle

Egg-laying females prefer bark near pruning wounds and other injuries, and often reinfest old masses.[1]

Damage and signs

  • Larvae do little harm to cambium or wood; they rarely girdle or kill trees but may kill or break limbs on young trees.[1]

Health risk

They feed on conifers; UC IPM mentions no risk to people.[1]

Control

Prevention

Protect trees from injury and avoid unnecessary pruning, since wounds attract egg-laying moths.[1]

Monterey, Aleppo, Bishop, Japanese black, ponderosa and shore pines are most susceptible; Canary Island and Italian stone pines least.[1]

Common questions

What are the pink, gummy blobs on my pine trunk?
Probably pitch moth masses, formed as larvae feed beneath them.[1]
Will pitch moths kill my pine?
Rarely; they seldom girdle trees, though young trees may lose limbs.[1]

Sources

  1. University of California Statewide IPM Program, “Pest Notes: Pitch Moths (Publication 7479).” ipm.ucanr.edu/PMG/PESTNOTES/pn7479.html (accessed 2026-10-06)
  2. iNaturalist, “Synanthedon novaroensis taxon page (order and family).” www.inaturalist.org/taxa/232120 (accessed 2026-10-06)

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