Pest spreads on border with Germany – city releases nematodes

A plague is spreading. A city in Switzerland is using an unusual method to combat it. Tiny worms are supposed to help against Japanese beetles.

Basel – It sounds like a plot from a horror film: The city of Basel in Switzerland wants to use nematodes to eradicate a voracious pest – the Japanese beetle. Nematodes – also known as roundworms – are tiny. They penetrate the larvae of the pests to kill them. A specialist company sprays a solution containing roundworms on green spaces and in parks. In neighboring Germany, Baden-Württemberg is trying to contain the pest with certain measures.

Basel uses nematodes to combat Japanese beetle plague

“We hope that this will help contain the Japanese beetle,” explains Simon Leuenberger, head of the green space maintenance department, to the news agency dpa-d. “But it will only become clear next year whether we will be successful.” To check this, soil samples will be taken.

Are nematodes dangerous for humans?

Roundworms are about 1 millimeter in size and there are up to 20,000 different species, including both harmful and beneficial ones. In particular, the predatory nematodes of the genus Heterorhabditis are gaining in popularity, according to expert portals such as My beautiful garden are becoming increasingly important in horticulture. They can destroy harmful larvae that live in the soil, such as those of the black vine weevil and the garden chafer. The nematodes are harmless to humans and other animals.

The use of this invisible biological weapon requires patience. For stubborn pests such as the garden chafer, treatment with nematodes should be carried out for two to three years in a row in order to gradually reduce the pest population. Private gardeners can also order nematodes online. There you can find special offers against fungus gnats or the black vine weevil.

Japanese beetles eat through football pitches and vineyards

The Japanese beetle attacks orchards and vineyards. The voracious beetle even attacks FC Basel’s lawn. The larvae of these beetles feed on roots, while the adult beetles prefer leaves, flowers and fruit. Even ornamental plants such as roses and wisteria are not safe from this invasive species.

Switzerland fears the worst scenario: a widespread spread of the pest. According to the Swiss SRF, the damage to agriculture amounts to several hundred million francs. The “infested area” is still manageable, they say. But after the first finds in Ticino (2017), the first Japanese beetle population made it across the northern Alps. In July 2023, the first Japanese beetles were discovered in Kloten, then in Zurich and now on the football pitch of FC Basel. It is still unclear whether the beetle was introduced via the infected patches of lawn.

Japanese beetle invasion in Germany?

The district of Lörrach (Baden-Württemberg) is reacting to the Japanese beetle infestation in Basel. “Infestation and buffer zones” have been set up from which no shredded plant material may be transported. In some of these buffer zones, special collection points have been set up where the material can also be disposed of “unshredded”.

In Baden-Württemberg, the spread of the Japanese beetle has been closely monitored for some time. In 2021, a single Japanese beetle was discovered in a pheromone trap in Freiburg. The Augustenberg Agricultural Technology Center (LTZ) suspects that this specimen was imported as a “stowaway” from Italy by train or truck. By 2023, the number of Japanese beetles discovered had risen to three.

The Japanese beetle (Popillia japonica), as its name suggests, comes from Japan. At the beginning of the 20th century, the Japanese beetle was introduced from Asia to the USA. In the 1970s, the beetle first appeared in Europe in the Azores. Then in 2014 in Italy. According to the LTZ, the pest probably arrived in 2008 via the Cameri military airfield in the Piedmont region or the Milan-Malpensa airport in the Lombardy region. In 2017, the beetle also reached Ticino in Switzerland. In 2023, a population north of the Alps was discovered for the first time near Zurich. (ml)