- Basel Resorts to Threadworms as a New Strategy to Combat Japanese Beetles
To combat the expanding Japanese beetle problem, Basel, a major city in Switzerland near the German border, is experimenting with threadworms in its public parks and sports facilities for the first time. A specialized firm applied a mixture containing nematodes, which are unseen by the human eye, onto the grassy zones. These nematodes aim to render the Japanese beetle larvae in the soil harmless.
According to Simon Leuenberger, responsible for maintaining green spaces in the third-largest city in Switzerland, the objective is to control the Japanese beetle with this approach. However, it won't be clear until next year if the strategy was successful, as soil samples will be collected for evaluation. So far, the beetle has been detected in twelve locations in the area.
These nematodes enter the Japanese beetle larvae and eliminate them, as reported by the cantons of Basel-Stadt and Basel-Landschaft. The nematode strains are also effective against the larvae of the dock beetle and garden chafer, assuring no harm to other animals and humans.
Applying the procedure on approximately 38 hectares is laborious, as the areas must be kept damp.
These beetles feed on more than 300 plant species.
In the city mid-year, a Japanese beetle population was identified. After the discoveries in Basel, preventative measures were taken by the district of Lörrach on the German side of the Rhine. Presently, there is an infestation zone, such as retaining plant material on the site. Lörrach was informed in advance about the new approach in Basel, and fortunately, the situation has remained steady since July, preventing the need for expanision of infestation and buffer zones.
The Japanese beetle (Popillia japonica) originates from Asia and is considered a pest in the EU. The insect poses a significant threat to viticulture, horticulture, and agriculture, impacting various plant species like roses, blackberries, grapes, orchards, vineyards, forests, green areas, and gardens by devouring nearly everything bare.
The Japanese beetle moved to Ticino from Italy in 2017 and subsequently spread to additional areas of the Alpine country. In neighboring Baden-Württemberg, some examples of this harmful beetle species were discovered this year, with experts fearing its introduction through freight traffic. A specimen was also found in Bavaria.
The concern about this invasive species is now so significant in Germany that even the Federal Ministry of Agriculture and the Julius Kühn Institute, the federal research institute for crop plants, have issued warnings.
Distinguishing features: White hair tufts
The Japanese beetle is roughly one centimeter long, featuring a metallic, shiny green head and brown wings. Five white hair tufts on each side of the abdomen and two white hair tufts at the end of the abdomen are notable features. The females reportedly prefer to lay their eggs in wet or waterlogged grassy areas, and the larvae that hatch from these eggs damage grass roots in meadows and grassy areas.
The Japanese beetle problem has also prompted neighboring Landkreis Lörrach to take preventative measures. They are closely monitoring their green spaces to prevent an infestation, following the lead of Basel. The strategy of using threadworms to control the beetle has sparked interest in nearby counties as well.
