Common name: Box tree moth
Scientific name: Cydalima perspectalis
Hosts: Box tree moth is an introduced pest that is native to Asia. Its preferred host is boxwood (Buxus species). Within the native range of the pest, it has been found on burning bush (Euonymus alatus) and Japanese spindletree (Euonymus japonicus), when these plants were growing near heavily infested boxwoods.
The insect was introduced into Germany in 2006 and since has spread through much of Europe.
In North America, the insect is currently found in Massachusetts, Michigan, New York, and Ohio, as well as parts of eastern Canada.
This is a serious pest that can completely defoliate and kill boxwood shrubs.
Box tree moth is not found in Illinois at this time.
Damage
Box tree moth is damaging in the larval (caterpillar) stage and can completely defoliate boxwood shrubs. Older caterpillars will eat the entire leaf, leaving only the midrib.
Once the leaves have been eaten, the caterpillars may also feed on the bark.
Entire plants can be killed by large populations of the caterpillar.
The caterpillars also produce webbing to hold leaves together to form shelter and a place for the larvae to overwinter in its cocoon.
Life Cycle
The life cycle of box tree moth is complicated. There may be two to five overlapping generations per year. This is dependent on the climate in any given locale.
Box tree moth overwinters as partially grown caterpillars, in different stages of development. It spends the winter in cocoons on the leaves, protected by webbing. If the host plant has been completely defoliated, this may occur on nearby leaves, away from the host.
Larvae begin feeding again in early to mid-spring, and then will pupate.
Because the overwintering larvae are in different stages of development, adult moths will emerge over a period of time in spring and early summer.
Adult moths have a mostly white body. The wings are white, edged in brown. There is also a form of the moth that is mostly brown with white spots on the forewing, but this form is uncommon.
Adult moths live about two weeks. Females will lay eggs, both singly and in clusters, on boxwood leaves.
The eggs hatch into larvae (caterpillars). The caterpillars, when newly hatched, are greenish-yellow with black heads. Older caterpillars develop thick black stripes and thin white stripes along the length of their bodies, as well as black dots with white margins.
The caterpillars will feed all season.
Management
Cultural Management
Hand-picking can be used on small populations.
Chemical Management
Insecticides are available for treatment of this pest.
The pesticide information presented in this publication is current with federal and state regulations. The user is responsible for determining that the intended use is consistent with the label of the product being used. Use pesticides safely and wisely; read and follow label directions. The information given here is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement made by The Morton Arboretum.
For more information, contact The Morton Arboretum Plant Clinic at 630-719-2424 or plantclinic@mortonarb.org.