Oak processionary moth caterpillars can trigger rashes, respiratory problems and, in rare cases, allergic shock

An insect infestation is spreading across Berlin, forcing closures and health warnings in parks, sports grounds, and residential areas, German media has reported. The culprit is the oak processionary moth caterpillar, a tree-killing pest covered in toxic stinging hairs.

The insect, scientifically known as Thaumetopoea processionea, is a moth species whose caterpillars emerge between May and July. While the moth itself is harmless, the caterpillars develop hundreds of thousands of microscopic toxic hairs that can travel up to 200 meters on the wind and cause rashes, eye irritation, and respiratory problems. In severe cases, exposure can trigger allergic reactions and even anaphylactic shock.

The infestation has been spreading across Berlin for years, but officials say several districts are seeing a sharp rise in affected trees this summer. According to Bild, authorities and park operators have issued warnings across Berlin and Potsdam, closing off infested areas and temporarily shutting parks, sports facilities, and pedestrian routes.

The hardest-hit areas are Charlottenburg-Wilmersdorf, Treptow-Kpenick, Steglitz-Zehlendorf, and Spandau, which contain many of Berlin's oak-lined streets and parks.

According to B.Z. daily, the caterpillars have also spread throughout a Jungfernheide housing estate of more than 11,000 residents, infesting everything from facades and cars to door frames, railings, and light fixtures.

Local politicians have criticized what they describe as poor coordination between authorities. Health agencies have limited powers to intervene because the caterpillars are classified as an allergen rather than a public-health pest, while plant protection rules restrict the use of certain biocides.

Critics are calling for a coordinated response from district authorities, the Berlin Senate, and housing companies, including earlier treatment of oak trees and more aggressive nest removal. F rustrated residents have also launched a petition demanding a binding protection plan for Jungfernheide, which has already attracted more than 4,500 signatures.

Last year, Berlin's Senate Department for the Environment recorded 5,032 infested oak trees at 881 locations across the city. Experts predict that the outbreak will worsen as warm, dry weather favors the caterpillars' spread, with forecasters expecting hotter and drier-than-average conditions across Germany and Central Europe this summer.

The pest is not confined to Germany. The oak processionary moth is established across much of Europe and has been recorded from the Netherlands and France to Denmark and the Mediterranean. It was accidentally introduced to the UK in 2006 and is now established in Greater London and parts of southeast England, prompting a government warning on Saturday urging the public not to touch the insects or their nests.