The longhorn beetle (Anoplophora chinensis, also Chinese hardwood buck) is one of the most dangerous pests, especially on citrus plants, but also on deciduous trees. A few years ago he also appeared in Germany. The beetle destroys deciduous trees and is therefore subject to notification.
The first infected plants came from the stock of a large supermarket chain, which sold more than 100, 000 Japanese maple trees in Germany in May 2008. The trees were labeled "Acer palmatum". The Julius Kühn Institute (JKI) therefore urgently asked all people who bought young Acer palmatum in a nursery or supermarket to check their plants several times a week for traces of drilling chips, holes or adult beetles and suspicious plants or beetles report to the nearest competent plant protection service in your state.
The larvae of the longhorn beetle live hidden for one to two years in the wood of the trees. Therefore, infested trees can often only be recognized by the almost round, one to 1.5 centimeter holes, usually near the roots, but also by the roots from which the beetles drill out of the wood. Before the beetles hatch, drilling chips can sometimes be seen at the base of the trunk, on the surface of the earth or in the ground litter. The main flight of the beetles in Germany begins in June.
A hole in the citrus beetle on a maple (Acer palmatum).
Photo: Bavarian State Research Center for Agriculture, Institute for Plant Protection
The longhorn beetle has been on the list of harmful organisms in the European Union for many years, the introduction of which into the EU member states must be prohibited and their spread within the EU must be prevented. The beetle attacks many local, also completely healthy deciduous trees such as maple, beech, willow, birch, plane tree, hazelnut, horse chestnut or apple trees and can cause them to die. The plants suspected at the time came from a shipment imported from China to the Netherlands in December 2007, or in part from a tree nursery in the Netherlands. There, after the beetle's first findings, the controls were massively strengthened.