Boxwood Psyllid
Cacopsylla buxi
The most common insect pest of boxwood, a small sap-sucking psyllid whose nymphs make the new leaves cup. The damage is mainly cosmetic, slowing and distorting the spring flush, and established boxwoods tolerate it well.
🔎 How to spot it
The adult is a small greenish insect about an eighth of an inch long with long transparent wings and strong jumping legs, resembling a miniature cicada. The nymphs are light green and produce white, waxy filaments that give them a woolly look as they feed on the opening buds. Cupped leaves at the shoot tips are the classic sign.
🥀 Damage it causes
Nymphs feed on the buds and young leaves in spring, causing the new leaves to cup and curl and the twig growth to be stunted. The cupping protects the nymphs as they feed, and the affected tips look spoon-shaped and stunted. The injury is aesthetic and does not seriously harm the health of an established plant.
🛡️ Prevent it
Inspect boxwoods as the buds open in spring for cupped tips and the woolly nymphs, and prune out infested tips on small plants to remove them. Because there is only one generation a year, removing or treating the spring nymphs prevents most of the damage for the season. Tolerate light cupping on vigorous plants.
🧯 If it is already here
Soft materials such as insecticidal soap and horticultural oil work well when timed to the spring flush, smothering the eggs and young nymphs before they cause cupping. Where infestations are heavy, a labeled systemic may be used, though treatments can take two weeks or more to take full effect. Targeting the early nymphs gives the best result.
💡 Good to know
The boxwood psyllid has one generation a year and overwinters as tiny orange eggs tucked under the bud scales, which hatch in spring as the buds open. It feeds only on boxwood, and American boxwood is generally less affected than English boxwood. Because the harm is cosmetic, control is optional on many plants.
For educational and informational purposes only. Pest control advice is general guidance drawn from university cooperative extension sources; always identify a pest positively and read and follow the label on any product before use, especially around food crops, children, and pets.