Boxwood Psyllid - Shrubs

Boxwood psyllid damage (cupping of leaves)

The boxwood psyllid, Psylla buxi, causes a characteristic cupping of the leaves on the terminal and lateral buds of boxwood. This insect can overwinter as an egg, or as a first instar nymph under the bud scales. As the buds develop in the spring, the eggs hatch and nymphs emerge to infest the leaves. The feeding causes the leaves to curl and form a cup which encloses the greenish colored nymphs.

Psyllid nymphs with wax

The nymphs produce a white, waxy secretion which may cover part of the body or small waxy pellets beside the nymphs. The greenish adults emerge late May into June, mate and lay eggs under the bud scales. Only one generation occurs each year. This pest causes aesthetic damage to American boxwood and English boxwood.

 Boxwood psyllid adult

Management

Boxwood psyllid nymphs may be controlled with horticultural oil, or insecticidal soap sprays in April and May. Adults may be controlled by a registered residual insecticide in late May into June. Sprays are only necessary if infestations are heavy.