Citrus Longhorn Beetles
(Asian longhorned beetle, ALB, Starry sky beetle)*Anoplophora chinensis* / *A. glabripennis*
Identification & Appearance
Citrus longhorn beetles (Anoplophora chinensis) and Asian longhorn beetles (A. glabripennis) are large wood-boring beetles. Adults measure 20-40mm, cylindrical, jet black and glossy, with white star-like spots on the elytra. Antennae are extremely long (1.5-2x body length), banded black and white. Larvae measure 30-50mm, white to pale yellow, cylindrical with dark brown heads. They bore into tree trunks and branches for 1-2 years. Adults emerge in summer through 10-15mm round exit holes. They are important quarantine pests globally.
Habits & Hiding Places
Longhorn beetles infest broadleaf trees: citrus, willows, maples, poplars, and plane trees. Indoors, larvae bore into large potted plants and bonsai (lucky trees, money trees, ficus bonsai). Key signs: frass and wood dust expelled from bore holes, branch dieback progressing downward, and round exit holes. Adults are active May through August, feeding on tender bark and leaf stalks. They are attracted to light at night. Ground-floor units near trees and landscaping are most affected.
Health Risks & Damage
- Larvae tunnel inside branches, destroying vascular tissue and killing branches and entire plants. A large potted tree can die within 1-2 months from active infestation.;
- Bore holes allow pathogen entry, causing rot and accelerating tree death.;
- Adult feeding notches leaves and bark, affecting appearance and vigor.;
- Frass expelled from holes contaminates balconies. Audible chewing sounds can be heard at night from active larvae.;
- Control: probe bore holes with stiff wire to kill larvae, inject insecticide into holes with a syringe, prune and destroy severely infested branches. Capture adults during summer to reduce egg-laying.
Season & Region
Cosmopolitan. Adult emergence peak May–Aug.