Xylotrechus rusticus

Gray tiger longhorn beetle

Description

Xylotrechus rusticus, known as the gray tiger longhorn beetle, is a wood-boring beetle from the Cerambycidae family, distributed throughout Eurasia, from Spain to Japan. This species is polyphagous and primarily targets dead or dying deciduous trees, especially poplars (Populus spp.) and willows (Salix spp.) in floodplain forests, while also favoring beech (Fagus sylvatica) in montane forests. The larvae burrow into branches and trunks, creating galleries in both soft and hardwood deciduous trees. In hardwoods, they produce short, irregular tunnels, whereas in softer woods like poplar, the galleries penetrate deeper. Although this damage rarely affects tree health in Europe, it can weaken trees, reducing their structural integrity and aesthetic appearance. It is considered a significant technical pest.

In China, Xylotrechus rusticus causes substantial and widespread forest damage, especially in poplar plantations in the northeastern regions. Unlike in Europe, where the beetle mainly infests dead or weakened trees, in China, it actively attacks living trees, particularly poplars. The larvae create extensive tunnels within the trunks, compromising tree stability, making them susceptible to wind damage, and often leading to tree death. This has led to large-scale tree mortality across vast areas. The outbreaks in China highlight the potential of this beetle to become a serious invasive pest capable of affecting large forested areas, posing a potential threat to other regions where suitable host trees are prevalent.

Symptom

Affected wood displays irregular tunnels beneath the bark, extending into the sapwood, with exit holes and frass deposits, leading to weakened and visibly damaged branches or trunks.

Tree Species: Elm, Birch, Maple, Lime, Poplar, Willow

Part of a plant- attacked: Tree trunk, Branch

Pest significance: Harmful

Pest Category: Insects

Invasive Species: No

Present in EU: Yes