Asian longhorn beetle
Fig. 1. Damage caused by the Asian longhorn beetle in an urban area
Fig. 2. A. glabripennis exit holes in the upper part of the trunk of a maple tree
Fig. 3. A. glabripennis female laying eggs
Fig. 4. Sap oozing from an oviposition site
Fig. 5. Accumulation of frass in forks of branches caused by A. glabripennis
Fig. 6. A fully developed larva of the Asian longhorn beetle
Fig. 7. Signs of A. glabripennis maturation feeding in the canopy
Fig. 8. Tunnels in wood caused by A. glabripennis larvae
Adults are 25–35 mm long beetles. The body is black and shiny. The beetle has up to twenty irregularly shaped white to yellowish spots on elytra. Antennae are longer than the body and striped. Eggs are white, elongate, 5–7 mm long. Larvae are cream white, with a dark brown to black head, without legs. A grown larva measures 30–50 mm in length. It has a chitinous brown mark on the dorsal side of the prothoracic segment. The pupa is 27–38 mm long, cream white, with clearly visible extremities of the adult beetle. The Asian longhorn beetle is highly polyphagous. Larvae develop in hardwoods of more than hundred species, in the upper part of the tree trunk and in thick branches. Development in the wood lasts one to three years. Adults emerge from May to September through round, 10 mm wide exit holes.
Various hardwoods in natural habitats, nurseries, plantations and urban areas: maples (Acer spp.), birches (Betula spp.), willows (Salix spp.), horse chestnut (Aesculus hippocastanum), poplars (Populus spp.), alders (Alnus spp.), hornbeams (Carpinus spp.), beeches (Fagus spp.), ashes (Fraxinus spp.), plane trees (Platanus spp.), cherries (Prunus spp.) and others. In Europe, the species has been found only in urban areas on maples (Acer spp.).
The Asian longhorn beetle originates from SE Asia and is a quarantine pest for Europe. The species has been found and/or intercepted in several European countries, of which Austria is in the Refocus area. The main introduction pathway for A. glabripennis is wood packaging material. It has been neither found nor intercepted in Slovenia so far.
Main damage is caused by larvae, which feed on wood and create extensive tunnels in the live plant tissue. The mechanical damage results in the disruption of water and nutrient transports, leading to plants losing their vigor and defense ability and is followed by wilting and canopy dieback. The Asian longhorn beetle attack generally leads to the death of the plant. Maturation feeding on bark of young shoots and on leaves causes minor damage. A. glabripennis causes extensive economic damage in plantations and urban areas, mainly due to loss of trees. The impact of the Asian longhorn beetle in native habitats, such as forests, in its introduced range is not known.
The citrus longhorn beetle (Anoplophora chinensis), which is also a quarantine pest. The main difference is in the texture of the base of elytrae, which is smooth in A. glabripennis but covered with small granules in A. chinensis. Also, A. chinensis larvae develop in the lower part of the host, lower trunk and in roots. Similar symptoms and signs are caused also by certain native insecs, such as Cerambyx cerdo, Morimus funereus, Lamia textor and Cossus cossus.