boxwood psyllid damage

Cupping symptoms of boxwood psyllid damage

Updated: April 21, 2021

Key points

  • 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.
  • 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.
boxwood psyllid nymphs with wax
Psyllid nymphs with wax inside a cupped boxwood leaf. Photo: John Davidson, UMD
boxwood psyllid adult
 Boxwood psyllid adult. Photo: John Davidson, UMD

Management

  • This pest causes aesthetic damage to American and English boxwood. Prune out and dispose of infested branch tips. Sprays are only necessary if infestations are heavy. 
  • 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.

Rev. 2020