“Houston, we have a problem!” – even though space has very little to do with it here.

In fact, the problem in this case is as down-to-earth as it gets: an insect, moreover quite clumsy, large, and lazy.

The Asian longhorned beetle (Anoplophora glabripennis)—an elegant, glossy black beetle with white spots—is one of the many so-called “alien” species, not because it comes from outer space, but because it has been introduced—intentionally or accidentally—into a territory where it naturally doesn’t belong. The term “Asian” in this case already makes its origin clear.

Up to this point, however, there’s no real problem—apart from the fact that there’s a new black insect roaming through the towns and countryside of Veneto.

Too bad that this handsome longhorn beetle is included in the list of quarantine pests of concern for the European Union [1], as well as in the list of priority quarantine organisms for plants [2].

Exactly, you got that right: quarantine! Meaning that this long-antennaed insect is anything but harmless.

In fact, it can kill healthy trees within just a few growing seasons. What’s more, it’s polyphagous—meaning it attacks many plant species (all broadleaved), including some of the most common in our gardens and along our city streets: maples, lindens, plane trees, and poplars.

Where does this insect come from?

Global trade has led to the forced and unintentional migration of many insect species. For the Asian longhorned beetle, this is precisely the most likely route of entry into Europe: packaging materials, pallets, and other untreated wood, as well as imports of plants, bonsai, and other infected nursery material.

The first reports of the species in Europe were recorded in Italy at the end of the 1990s, in Lombardy. From there, it was soon observed in Austria, France, and Germany. After the detection of a large outbreak in the province of Milan in 2007 (not eradicated until 2022), the species quickly spread to Veneto, where it culminated in an outbreak in the province of Treviso in 2009 [3].

Why is it so dangerous?

The Asian longhorned beetle attacks the trunk of its host plants directly. After the female lays her eggs on the middle-to-upper part of the trunk and on branches, and the eggs hatch, the young larvae develop by feeding on the wood. They bore deep into the tree, moving upward in a spiral pattern. Once they complete their larval stage and transform first into pupae and then into adults, the latter emerge from the wood by creating circular exit holes about 1 cm in diameter [3].

This entire life cycle irreversibly compromises the vitality of the infested tree, damaging its vascular system.

How can it be controlled?

Regional protocols for the control and eradication of the species are in place in all affected areas. In terms of prevention, efforts focus on monitoring nursery stock imported from the Far East and treating packaging materials.

Control of the species is mandatory in both Europe and North America for the purpose of eradicating outbreaks. However, the only truly effective measures consist of cutting down infested trees and subsequently chipping or incinerating the wood.

There have also been attempts at biological control using entomopathogenic fungi, insecticides, and endotherapeutic treatments, though these are not yet feasible on a large or cost-effective scale.

Figure 1: Left: maple tree attacked by Anoplophora glabripennis. Right: Anoplophora glabripennis larva on maple tree. Villaverla (Vicenza, Italy). Photo. Author. 27.10.2025