Cherry: Cherry bark tortrix

Biology

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 living tissue of the tree’s bark. Graft unions of ornamental trees are preferred sites for attack. Larvae do not penetrate the hard wood of the tree. During feeding, CBT larvae construct a frass tube consisting of fecal pellets and webbing. The frass tube is the location for pupation once CBT has completed the larval stage. Frass tubes are an excellent indication of CBT infestations and susceptible trees should be regularly monitored for frass tubes.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Avoid any mechanical injuries or large pruning cuts.
• Conserve parasitic wasps and other predators by reducing pesticide usage. Do not make unnecessary pesticide applications to the trunk of the tree unless CBT is your target.
• Do not purchase susceptible trees. Mount Fuji Oriental and Weeping (or Higan) Flowering cherries are very susceptible to CBT attack.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• Only use pesticides for large infestations.
• For best results, apply in mid-September to early October when temperatures are warm and conditions are dry.
• Treat only infested areas, such as the trunk or graft union.
• Do not treat the canopy.
• Drench the frass tubes with a low-pressure spray until run-off.
• Mix only small amounts of pesticides, very little mixed material is needed to control CBT. Less than one liter of mixed product is more than enough to treat most highly infested trees.
• Esfenvalerate is toxic to bees. Do not apply products containing esfenvalerate on or near blooming plants.
• To minimize risk to bees, apply in the evening after bees have stopped foraging for the day.

Approved Pesticides

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

• Monterey Bug Buster II
  Active ingredient: esfenvalerate [EPA registration number: 1021-1778-54705]
• This list may not include all products registered for this use.

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