The cherry bark tortrix (CBT) has become an important Pacific Northwest pest of rosaceous trees and shrubs, affecting plants such as:
- Mountain Ash
- Pear Trees
Initial larval feeding stimulates an oozing of a gum-like substance. Other signs of infestation include reddish-orange "frass tubes" that protrude from the bark, cracking and curling of bark, cankers and large swelling. Serious infestation results in branch death followed by tree death.
CBT larvae overwinter under the bark of host trees, where they feed on living tissue. Mature larvae undergo transformation in the frass tubes in spring, emerging as adult mothers from late April to early May (with flight activity in June). Less mature larvae transform later, creating more flying activity in August.
Management and Treatment
Severely infested plants should be removed and destroyed. To determine the infestation, monitor the host plants for the presence of pupal chambers. Remove chambers and loose bark, then set pheromone traps between May and September to trap adult moths.
For CBT management, invigorate trees with fertilization and watering during dry periods. Practice good pruning techniques, and prune during the dormant season. Cover injured bark and pruning wounds with pruning seal. Dormant oil and insecticide applications to trunk and branches may help reduce the populations of overwinter larvae.