Invasive Asian Insect Threatens Crops and Gardens; Recently Discovered in Alsace

Japanese scarab, Popillia Japanica, is one of the twenty most dangerous species followed by the European Union. In July 2025, two specimens were spotted in Huningue, Alsace, a few steps from the Swiss border. The alert was quick to mobilize the authorities of the three countries concerned. In Switzerland and Germany, the first cases date back to 2017 and 2021. From the first catches, cross -border meetings were set up to harmonize the means of struggle.

France 3 Grand Est highlights the role of these exchanges between researchers and field services. They make it possible to deploy the traps in strategic places and to adapt the responses according to the local evolution of the threat. Surveillance is therefore organized on a regional scale, because this insect does not know the borders.

The Japanese scarab slips into the faults of our exchanges

Originally from Asia, the Japanese beetle found a favorable land in Europe. He travels hidden in plants, earth or trucks. Its installation in Italy dates from 2014 and could never be completely contained. The Haut-Rhin prefecture recalls that its arrival in Basel in 2024 sparked the creation of a surveillance area in six French border municipalities, with more than 70 traps installed in Alsace.

This insect attacks more than 300 plant species. It gnaws at the leaves and weakens the roots, endangering crops, fruit trees, meadows and even lawns. Rosiers, poplars and maples are not spared. This diversity of prey makes it more difficult to contain.

Preserving floors and crops involves a collective alert

Faced with this threat, the authorities rely on a three -step method. A first phase aims to detect homes, then a buffer area is set up, without trap, to avoid attracting insects beyond the perimeter. If a reproduction is confirmed, the plants are mowed and the ground covered with tarpaulins to prevent larvae from surviving.

But this strategy is not enough without the participation of the inhabitants. The prefecture invites everyone to report suspicious insects to the Draaf Grand Est, with supporting photo. An online document helps to recognize the beetle: copper -brown wings, green thorax, white tufts on the sides.

The analyzes are underway to check if colonies have already emerged. Because once established, the insect becomes difficult to eradicate. The success of the response therefore depends as much on technical means as on collective reactivity. At a time when ecological borders are erased, the slightest alert can change everything.