What's eating my trident maple?

Trident Maple is attacked by aphids, scale insects, and caterpillars outdoors, and deer may browse young foliage. Aphids are the most common problem, clustering on new growth in spring. Borers can weaken stressed trees. Good cultural care, horticultural oil in dormancy, and physical barriers manage most threats effectively.

Sticky honeydew on leaves, curling or distorted new growth, and sooty mold on upper leaf surfaces Knock off with a strong water jet; encourage natural predators (ladybugs, lacewings); use insecticidal soap for heavy infestations

Brown or white crusty bumps on branches; yellowing leaves and dieback of twigs in severe cases Apply dormant horticultural oil in late winter; scrub bark with soapy water; use systemic insecticide for heavy scale

Ragged holes in leaves or complete leaf stripping; frass (droppings) visible on foliage Hand-pick small infestations; spray Bacillus thuringiensis (Bt) for caterpillar outbreaks; beneficial wasps provide natural control

Bark rubbing and browsing of young shoots and leaves, especially in autumn rut and spring Tree guards on young specimens; deer-repellent sprays; wire mesh fencing around bonsai growing areas