Arborvitae: Cypress tip moth

Biology

The adult cypress tip moth (cypress tip miner) is a silver-tan moth approximately 1⁄4″ in length. The larvae are green, about 1⁄8″ long, and tunnel in the one- and two-year-old shoot tips. Damage is typically limited to tips of twigs. In late winter, damaged tips begin to turn brown. The larvae exit the mined areas in late winter or early spring to make cocoons. The exit holes are dark and may resemble symptoms of leaf blight, a fungal disease. The cocoon is a white, somewhat papery structure made in dead or living foliage. The adult moths appear on plants around May-June. Repeated heavy infestations can cause severe damage. Junipers are also infested.

Management Options

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

Non-chemical Management

Select non-chemical management options as your first choice!

• Western red cedar (Thuja plicata) is highly resistant to infestation.
• American arborvitae (Thuja occidentalis) is very susceptible.

Chemical Management

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

• Apply from late June to August.
• Avoid Sevin (carbaryl) if there is any possibility of pesticide drifting onto nearby blooming plants. These products are toxic to bees.
• Homeowners should not make foliar applications to trees over 10 ft tall.
• Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Approved Pesticides

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

• GardenTech Sevin Concentrated Bug Killer
  Active ingredient: carbaryl [EPA registration number: 264-334-71004]
• This list may not include all products registered for this use.

Additional Image