Basel: New Japanese Beetle Occurrence Discovered

A small population of the Japanese beetle was first found north of the Alps in Switzerland in Zurich-Kloten in 2023. Some individuals have now been discovered in Basel. The Cantons and federal government are working together towards a solution.

Feeding on over 400 plant species, the Japanese beetle represents a major threat to agriculture, horticulture and the environment. In Switzerland, Japanese beetle is regulated as a quarantine organism, i.e. there is a general obligation to report and control this insect species.

Distinguishing traits

Adult Japanese beetles are 10-12mm long (like a Swiss 5-rappen coin) with metallic copper-coloured elytra (wing cases). The small, white-coloured tufts of hair on the abdomen are characteristic: there are five small tufts on each side of the body, and two larger tufts on the abdomen.

How can introduction be prevented?

The Japanese beetle spreads over long distances largely thanks to human assistance. The following measures are recommended:

• Check vehicles and suitcases/bags for beetles before your return journey
• Do not bring any plants, cut flowers, vegetables or fruit back home from your holiday, as they could be a vehicle for introducing other pests and diseases as well as Japanese beetle.

What to do if you suspect Japanese beetle:

• Trap, photograph and freeze beetle
• Make a note of the location, and if possible the name of the plant on which the insect was observed
• Inform the responsible Cantonal Plant Protection Service

Increasing problems with non-indigenous species

Increasingly, non-indigenous species like the Japanese beetle are spreading across Europe and Switzerland. Among the reasons for this are globalised trade and human mobility.

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