Citrus Long-horned Beetle (Anoplophora chinensis) — identification, habitat & look-alikes

The citrus longhorned beetle is a large black beetle with white spots and long black-and-blue-banded antennae, native to East and Southeast Asia. It does not live in the wild in the US; the only finds were beetles on imported bonsai trees in nurseries, and they were eradicated. Its larvae bore into the base of living trees, so it is treated as a regulated pest.

Appearance

Appearance: About 1–1⅜ in (25–35 mm) long, shiny black with white spots on the wing covers. The antennae are longer than the body and banded black and pale blue.

Look-alikes

Asian longhorned beetleAnoplophora glabripennis

The citrus longhorned beetle has many small, wartlike bumps at the base of the wing covers; the Asian longhorned beetle's wing covers are smooth there. A 10x hand lens or close-up photo is usually needed.

Why they get mixed upBoth are large, shiny black beetles with white spots and banded antennae, and both are invasive pests.

Whitespotted sawyerMonochamus scutellatus

The whitespotted sawyer has a single white dot where the wing covers meet at the base; females are brown and speckled. It breeds in pines, spruces, and fir, not in broadleaf trees.

Why they get mixed upIt is a common native long-horned beetle across much of the US and is often reported as an invasive Anoplophora.

Where it lives

Typical habitats: Orchards
Street and yard trees
Nurseries
Range: Native to China, Korea, Japan, Taiwan, and Southeast Asia. It has been introduced to several European countries, including Italy and France, mostly on nursery plants. In the US, beetles turned up in a Georgia nursery in 1999 and a Washington nursery in 2001, both on imported bonsai trees, and were eradicated; it is not established.

Behavior

Diet: Adults chew the bark of twigs and feed on leaves of their host trees.
Activity: Adults are active mainly from May to July; in Korea they emerge from mid-June to mid-July.

Life cycle

Larva: The female chews a T-shaped slit in the trunk, branches, or exposed roots and lays an egg inside. Larvae feed under the bark, then tunnel into the wood. Egg to adult takes about one to two years, and up to about three depending on climate. Adults leave round exit holes about ⅜–¾ in (10–20 mm) across, usually near the base of the trunk.
Caterpillar food plants: Hardwoods from more than 85 plant genera, including citrus (hence the name), maple, willow, poplar, apple, pear, and oak.

Name and classification

About the name: Many sources, especially in Japan, call the Japanese population Anoplophora malasiaca. Since 2002 this name has generally been treated as a synonym of A. chinensis, though Japanese sources often still use the older name.