WSU Extension

Hortsense

Arborvitae
 
Disease
Berckmann's blight 
Cedar flagging 
Leaf blight 
Shoot tip dieback 
Twig blight 
Insect
Cypress tip moth 
Flat-headed and shothole borers 
Juniper scale 
Juniper webworm 
Leafminers 
Spider mites 
Spruce bud scale 



print version| pdf version| email url    
Caption: Arborvitae cypress tip moth damage
Photo by: R.S. Byther
  
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

+ Show larger images

 
Caption: Arborvitae cypress tip moth damage
Photo by: R.S. Byther
Caption: Arborvitae cypress tip moth damage
Photo by: A.L. Antonelli