Cypress tip moth

Species of Argyresthia mine on plants in Cupressaceae. Cypress tip moth, Argyresthia cupressella, is also known as cypress tip miner and A. thuiella, the arborvitae leafminer. These insecst can mine the foliage of arborvitae, cypress, juniper, redwood; and white cedar, respectively. 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:

Natural Resources Canada webpage on Arbovitae leafminer.

Natural Resources Canada 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.

Some of the damage and possibly infested twigs can be sheared off in light infestations.

Chemical control may be warranted when large populations of miners are present. Soil applications of systemic insecticides (imidacloprid) in the early spring target the larval stages within the mines. Some guidelines suggest applications to control larvae in the mines from 150-260 Growing Degree Days(GDD) and again in August (1800-2200 GDD). 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 (533-700 GDD). Good control with one application of spinosad is reported from one trial. When cocoons appear in the spring, foliage can be shaken to assess presence of the tiny moths. Check the PNW Insect Management Handbook for chemical management information for control of cypress tip moth in nurseries.

Orginal publication: 4/15/2004
Latest revision: 12/19/2016

 

Author: R.L. Rosetta, Extension Nursery Integrated Pest Management, Department of Horticulture, Oregon State University

Cypress tip moth cocoons. Two cocoons spun between scales

Cy. press tip moth cocoons. Two cocoons spun between scales

Close up of Cypress tip moth damage and emergence hole.

Close up of Cypress tip moth damage and emergence hole.

Cypress tip moth larval emergence hole

Cypress tip moth larval emergence hole

Cypress tip moth caterpillar in arborvitae

Cypress tip moth caterpillar in arborvitae

Cypress tip moth larva in arborvitae

Cypress tip moth larva in arborvitae

Cypress tip moth mined arbovitae scales

Cypress tip moth mined arbovitae scales

cypress tip moth Newly hatched larva next to pollen grain. Photo: Jim Young

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

Newly spun cypress tip moth cocoon with visible larva

Newly spun cypress tip moth cocoon with visible larva

Cypress tip moth damage in arborvitae

Cypress tip moth damage in arborvitae

Cypress tip moth damage closeup

Cypress tip moth damage closeup

Defoliation from tip moth damage

Defoliation from tip moth damage

Cypress tip moth damage in arborvitae

Cypress tip moth damage in arborvitae

Cypress tip moth damage in arborvitae

Cypress tip moth damage in arborvitae