German cities shut schools and parks over oak processionary caterpillar outbreak

A citizen in Berlin created a live, crowdsourced map that now shows over 400 oak processionary caterpillar nests across the city, prompting authorities to close affected school yards, playgrounds and sports fields. The map, developed by Britta Wunderwald, is also being used by residents in Hamburg and Munich.

The toxic hairs of the caterpillars cause skin irritation, allergic reactions and respiratory problems, leading to widespread closures in several German states. Bavaria, Berlin and Brandenburg report the most severe infestations, with Bavarian towns such as Nuremberg and Würzburg deploying specialist teams to suction the larvae from trees. Würzburg warned residents: “Halten Sie sich nicht unter Eichen auf!” (Stay away from under oak trees). In addition to manual removal, some regions have sprayed bacterial insecticide from helicopters over heavily infested areas.

Officials stress that the outbreak has been fueled by unusually warm weather, and that control measures avoid chemical insecticides. The coordinated response aims to protect public health while limiting damage to urban green spaces.