Friday, May 23, 2008

Nursery and Landscape - Boxwood Psyllid

Damage from the Boxwood Psyllid may be evident now. The following is information about this pest.

Boxwood Psyllid. Photo by Nancy Gregory, Extension Plant Diagnostician, UD

Boxwood Psyllid Damage. Photo by Brian Kunkel, UD Ornamental IPM Extension Specialist.

The Boxwood Psyllid, Cacopsylla busi (Linnaeus) occurs wherever boxwoods are grown. It causes the cupping of leaves and may affect twig growth, but the damage caused is purely aesthetic and not as destructive as other boxwood pests.

Plants Attacked

Boxwood psyllid is a common pest of all boxwoods, but the American boxwood (Buxus sempervirens) is most susceptible.

Insect Identification

The small, orange eggs are laid between the bud scales with only the tip of the egg protruding past the edge of the scale. The nymphs are yellowish and covered in a white waxy exudate. The

Life History

Winter: Over-winters as a tiny, orange egg deposited in the bud scales.
Spring: The eggs hatch when the buds of the host plant open. The nymphs immediately begin to feed and develop a white flocculent material over their bodies. Winged adults appear by early June.
Summer: After mating, the female deposits her eggs between the bud scales of the host plant.
There is one generation each year in Delaware.

Damage Symptoms

The nymph stage damages the host plant by feeding on newly developing foliage, causing the leaves to become cupped. This cupping conceals the psyllid, and provides protection while feeding. Damage to the host plant is purely aesthetic.

Management Options

Insecticides should be directed towards the nymph in early May before leaf cupping occurs. Formulations of acetamiprid, azadirachtin (Ornazin 3% EC only), Beauveria bassiana, bifenthrin (Bifenthrin Pro Multi-Insecticide, Talstar F, Talstar Lawn & Tree Flowable, and TalstarOne Multi-Insecticide only), carbaryl, chlorpyrifos (Dursban 50W only), cyfluthrin and imidacloprid, deltamethrin (5SC only), horticultural oil (for immature psyllids), imidacloprid, insecticidal soap, and pyrethrins and piperonyl butoxide are labeled for psyllid management. Marathon 1% G and Marathon 60 WP are labeled for use only on plants grown in containers, flats, benches, or beds.

Management Hints: Treat when young psyllids are present in early May.

Information from Penn State University. Go to to view the factsheet with images.

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