Cherry bark tortrix
Enarmonia formosana
83 host plants
Last updated
Cherry bark tortrix larvae bore into the bark and branches of hawthorn, cherry, and crabapple trees, causing reddish-brown gummy exudate mixed with frass and silk at the entry point. Look for cracked or loose bark on trunks and larger limbs, especially near pruning wounds, graft unions, and branch crotches. Damage appears from spring through fall as larvae feed in the cambium. You may see small orange-colored frass tubes at cracks in the bark, which are diagnostic.
Prune out and destroy infested branches and twigs before mid-spring when larvae are active. Keep trees healthy through proper watering and avoid unnecessary wounding; trees stressed by drought or poor growing conditions are more attractive to the moth. Monitor weekly for gumming damage. Insecticide treatment is rarely needed in home settings; most populations remain light enough to manage through cultural practices and pruning alone.
Quick Reference
Monitoring & Action
Inspect Prunus bark in October for characteristic silk-and-frass tubes protruding from bark crevices. One generation per year.
The cherry bark tortrix (CBT) is a pest of most woody ornamental trees and shrubs in the family Rosaceae. CBT attacks Prunus (cherry, plum and peach), Malus (apple, crabapple), Pyrus (pear), Crataegus (hawthorn), Sorbus (mountain ash), Cydonia (quince), Pyracantha (firethorn) and Photinia. CBT has one generation per year and a prolonged flight period from April until September. All life stages occur within the host tree except for the eggs and adults. Eggs are laid singly on the bark surface. Hatching larvae penetrate the bark through openings (natural and mechanical wounds) and feed on the li
Cultural Controls
- Parasitoid wasps target the eggs, larvae, and pupae.
- Eggs that turn black indicate parasitism (likely by Trichogramma spp. wasps) and should not be disturbed.
- Avoid unnecessary pruning cuts or injuries to the tree during the summer flight period.
- Like most wood-boring insects, this pest is attracted to stressed trees.
- Keep trees as healthy as possible with appropriate watering, fertilizer applications, and pruning.
- Reduce humidity around trunks by...
Cherry bark tortrix occurs in this region in urban settings in lowland coastal valleys between the Cascades and Puget Sound. So far, it has not affected commercial fruit production regions in the PNW.