Cypress tip moth

Cypress tip moth, Argyresthia cupressella, is also known as cypress tip miner or arborvitae leafminer. This insect can mine the foliage of arborvitae, cypress, juniper, and redwood. The adult is a small gray, narrow-bodied moth which lays its eggs on the tips of new growth in the spring. The eggs hatch and burrow into and mine the branch tips. They remain there, feeding, through the winter until early spring when the greenish larvae emerge from their tunnels to spin white, silken cocoons in which they pupate between the branches. They have been found emerging and spinning cocoons in mid-April during 2004. The literature reports that adult moths emerge in Oregon from early May until late June with a peak in late May and early June. There is one generation a year.

Damage: The larval feeding causes the arborvitae tips to turn brown in the late winter and spring, later defoliating. Feeding damage will not kill the plants but can make them unsightly and unmarketable.

Additional information and images of this insect can be found at the following websites:

Conifer Defoliating Insects of British Columbia webpage on Cypress tip moth.

WSU Cooperative Extension: Cypress tip moth

Management:

One cultural control option is planting of resistant varieties of host plants. UC IPM online has a nice chart on the Susceptibility of Juniper (Juniperus spp.) and other Cupressaceae in California to the Cypress Tip Miner.

Chemical control may be warranted when large populations of miners are present. Applying a broad-spectrum, persistent insecticide to protect the new growth is timed to adult moth activity and the young larvae that hatch from their eggs. When cocoons appear in the spring, foliage can be shaken to assess presence of the tiny moths. The PNW Insect Management Handbook lists the following chemicals for control of this pest.

1. abamectin

2. acephate. A legal pesticide use not found on the pesticide label and not recommended by University of Idaho personnel.

3. bifenthrin

4. chlorpyrifos. Retail sale of chlorpyrifos (Dursban) for residential use was stopped as of 12/31/01.

5. cyfluthrin

6. imidacloprid

7. lambda-cyhalothrin

Tip moth damage

Photo: Rosetta

Cypress tip moth damage

Photo: Rosetta

Cypress tip moth damage closeup

Photo: Rosetta

Cypress tip moth damage and cocoons

Photo: Rosetta

Defoliation from tip moth damage

Photo: Rosetta

Mined arbovitae scales

Photo: Rosetta

Close up of damage and emergence hole

Photo: Jim Young, OSU

Larval emergence hole

Photo: Rosetta

Newly hatched (eclosed) cypress tip moth larva next to a pollen grain

Photo: Jim Young

Newly spun cocoon with visible larva

Photo: Rosetta

Two cocoons spun between scales

Photo: Rosetta

Page last modified 5/29/08