Pest profile

Cherry Bark Tortrix

Enarmonia formosana · Lepidoptera: Tortricidae[2]

The cherry bark tortrix is an invasive moth whose larvae feed under the bark of cherries and other rose-family trees, especially at wounds and graft unions.[1]

Cherry bark tortrix moth, a small moth mottled in orange, cream and dark brown
Cherry bark tortrix moth, a small moth mottled in orange, cream and dark brown. (c) Gabriel Casalanguida, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Larvae are 0.33 to 0.4 inch long, pale gray to flesh-colored with small pale spines and a yellowish-brown head.[1]
  • The first sign is reddish-brown, gum-like resin oozing from the bark, often mixed with droppings and silk.[1]
  • Soft, sawdust-like frass tubes about 1/4 inch long cluster at the trunk base, where branches meet the trunk and at graft unions.[1]
  • Adults are small moths about 1/3 inch across the wings, mottled yellow, cream and brown.[1]

Where it lives

First found in North America in British Columbia in 1989, it reached Centralia, Washington, by 1998 and is slowly moving south; it hasn't been seen spreading east, possibly because of the Cascades.[1]

US map: public records from 2 states since 1990 (GBIF).

Biology and life cycle

Larvae overwinter under bark, feed again in spring and pupate in silk tubes that stick out from the bark.[1]

Moths fly from late April to September, mostly in early morning, and lay eggs singly or in twos and threes on bark, mainly at wounds.[1]

Hatching larvae enter through natural or mechanical wounds and feed on the living bark tissue, never the hardwood.[1]

It attacks most woody ornamental trees and shrubs in the rose family.[1]

Damage and signs

  • Feeding on the cambium cuts the tree's nutrient supply and leaves it open to disease, insects, cold injury and other stress; it can kill the tree.[1]

Health risk

It feeds on plants; the PNW Insect Management Handbook mentions no risk to people.[1]

Control

Prevention

Check susceptible trees regularly for frass tubes, and confirm larvae before acting, since other insects cause similar damage.[1]

Avoid unneeded pruning cuts and injuries, and keep trees healthy with proper watering, fertilizing and pruning; stressed trees attract it.[1]

Sanitation

Remove heavily infested branches or trees.[1]

Biological control

Some wasps parasitize the larvae but don't control it well yet; avoid sprays that would disrupt them.[1]

Common questions

What are the sawdust-like tubes at the base of my flowering cherry?
Probably cherry bark tortrix frass tubes, made of droppings and webbing by larvae feeding under the bark.[1]
Can cherry bark tortrix kill a tree?
Yes. Larvae feed on the living tissue under the bark and may kill the tree.[1]

Sources

  1. Pacific Northwest Pest Management Handbooks (OSU, WSU, University of Idaho), “Cherry, flowering (Prunus): Cherry bark tortrix (Insect Management Handbook).” pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/cherry-flowering-prunus-cherry-bark-tortrix (accessed 2026-10-06)
  2. iNaturalist, “Enarmonia formosana taxon page (order and family).” www.inaturalist.org/taxa/320540 (accessed 2026-10-06)

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