Damage from the boxwood psyllid is mostly aesthetic. Depending on the situation, control may not be necessary. If the population is identified early enough, pruning out affected areas is a possibility. Another option is to use systemic insecticides like Xytect or Transtect, which work from the inside of the plant, controlling actively feeding psyllids.
This is not a pest that will kill or seriously disfigure plants. At most, it causes some curious looking foliage in the spring which grows out by summer. If control is necessary, timing must be made top priority. Though the adults feed later in the year, the nymphs do most of the damage and should be targeted. Boxwood leafminer will also be control by a Xytect or Transtect treatment.
Signs of Damage
- Leaf cupping from nymphal feeding is a distinguishing symptom
- As new foliage is rapidly growing, nymphs use their piercing sucking mouthparts to feed on young leaves and buds
- Later in the season the plant may outgrow the damage since there is only one generation per year
- Adults look similar to tiny cicadas and jump as plant lice in May and June
- Nymphs are covered with white, waxy filaments and be near developing leaves prior to May
- Eggs are orange, small, and are deposited in leaf buds in late summer and early fall
Photo: Brian Kunkel
University of Delaware, Bugwood.org
Photo: Whitney Cranshaw
Colorado State University, Bugwood.org
Trees At Risk
- Boxwoods are susceptible to leaf psyllids.
- Nymphs begin feeding on tender new leaves and buds.
- Nymphs go through several instars before molting into adults in early June.
- Adults emerge in late May or June as jumping plant lice.
- Insect overwinters as eggs laid in the buds.
- One generation per year.
Always refer to product label for rates and approved uses. Some images courtesy of forestryimages.org or Wikimedia Commons. Use of the images does not imply endorsement of treatments.