Citrus
longhorn beetle (Anoplophora chinensis)
What to Look Out For
The beetle is large (21-37mm) and black, with distinct white markings and long “horns” or antennae. The antennae are longer than the body and are black with white bands.
It could be found on a wide range of trees or shrubs including Acer, Alder, Citrus, Ficus, Hibiscus, Malus, mulberry, Pyrus, Rosa and Salix as well as ash, hornbeam, beech, hazel, birch, horse chestnut, and oak trees.
The beetles develop inside the tree, taking between one to three years to emerge. Feeding by the beetle larvae within trees creates tunnels in the stems and roots, making them susceptible to disease and wind damage. Prior to emergence, symptoms of infestation are difficult to detect (see below), and there are often no obvious signs to indicate the presence of a larva or pupa within the tree. However, large (6-11 mm) exit holes are left by the emerging adults in the stem, usually close to the ground.
The beetles can emerge at any time during the warmer months of the year, up until October, and usually live for about a month. During this period reproduction can occur if the beetles can manage to find a mate. It is thought that the female beetles prefer to lay their eggs either on trees from which they emerged, or in close proximity. The female chews through the bark of the tree to lay eggs singly in T-shaped slits, between the ground and a height of about 60 cm. Approximately 70 eggs are laid per female but the marks are difficult to spot, especially on small, thin-barked trees. Symptoms of infestation by CLB include
- Scraped sections of bark
- Chewed leaves and damage to the petioles by adults
- T-shaped egg slits in bark
- Saw-dust like ‘droppings’ or wood pulp around holes and larval tunnels in the wood under loose or thin bark
- Exit holes
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Page last modified:
16 July 2008
Page published: 16 July 2008