Stebbing’s longhorn beetle

Stebbing’s longhorn beetle (Xylotrechus stebbingi) is a wood-boring insect belonging to the family Cerambycidae. Originally native to Asia, this pest has successfully invaded several regions, including Southern Europe, where it poses a significant threat to orchard trees, ornamental plants, and forests.

The beetle exhibits a wide host range, attacking both healthy and stressed woody plants. It is particularly notorious for damaging fruit trees such as walnut, fig, apple, and cherry, as well as various broadleaved forest trees. Its ability to infest healthy trees in warmer climates makes it a serious challenge for agricultural production.

The life cycle of Xylotrechus stebbingi typically spans one year, though it can extend under cooler conditions. Adult beetles emerge in spring and summer to mate. Females lay eggs directly into bark crevices or pruning wounds. Larvae burrow deep into the sapwood and heartwood, creating complex gallery systems that compromise the structural integrity of the tree.

The primary damage caused by the larvae is the disruption of the vascular system, which hinders the transport of water and nutrients. Externally, the infestation is characterized by small exit holes on the bark and mounds of frass (sawdust) accumulating at the tree base. Affected trees often exhibit branch dieback, leaf wilting, and may eventually die if the infestation is severe.

Effective management requires a combination of strategies. Phytosanitary measures, such as monitoring imported wood and nursery stock, are critical to prevent further spread. In orchards, preventative actions include maintaining tree vigor through proper irrigation and fertilization, prompt removal of infested branches or dead trees, and applying approved insecticides to trunks during the oviposition period.