WSU Extension

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Caption: Arborvitae cypress tip moth damage
Photo by: R.S. Byther
  
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Arborvitae : Cypress tip moth
(revision date: 3/10/2017)


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

Non-Chemical Management
  • Western red cedar (Thuja plicata) is highly resistant to infestation.
  • American arborvitae (Thuja occidentalis) is very susceptible.
Select non-chemical management options as your first choice!

Chemical Management


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.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bonide Systemic Insect Control
    Active ingredient: acephate  |  EPA reg no: 239-2461-4
  • GardenTech Sevin Conc Bug Killer
    Active ingredient: carbaryl  |  EPA reg no: 264-334-71004
  • This list may not include all products registered for this use.
Images
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Caption: Arborvitae cypress tip moth damage
Photo by: R.S. Byther
Caption: Arborvitae cypress tip moth damage
Photo by: A.L. Antonelli