- Cupped leaves
- Waxy filaments under leaves
- Slender green insects in cup
Boxwood psyllids will feed on young expanding leaves at end of twigs and cause them to cup. The accumulation of cupped leaves will change the visual texture of the plant, but will not harm its health. White waxy filaments can be found under cupped leaves.
Boxwood psyllids overwinter as eggs between bud scales. Eggs hatch into deep green wingless nymphs that suck plants fluids, cup leaves, and produce waxy filaments. Adult insects are lime green with long clear wings. There is one generation per year.
Injury may be unsightly, but it does not harm plant health, so treatment is not warranted to keep plants alive. Pruning of cupped leaves before eggs hatch in late May can reduce injury. To avoid injury that cups leaves, plants can be sprayed with foliar insecticides before new leaves are cupped. Although soil applied systemic insecticides can protect plants, we do not list these because these products need to be applied before plants bloom to be effective. This early application will harm pollinators.
Active Ingredients include: Acephate, Acetamiprid, Bifenthrin, Cyfluthrin, Horticultural oil (Paraffinic or superior oil) , Insecticidal soap (Potassium salt of fatty acid), Malathion, Permethrin, Pyrethrin, Spinosad
