Significantly greater infestation by oak processionary moths

According to the Plant Protection Agency, more than 10,000 locations infested with the oak processionary moth were recorded in 2026. (File photo)

This year, more than 10,000 locations across Berlin were identified as being infested with the oak processionary moth.

That is nearly twice as many as in the previous year, according to data from the Pflanzenschutzamt (Plant Protection Agency) included in the Senate’s response to a written inquiry. The population has been tracked for more than ten years. The data also shows significant increases from 2019 to 2020 and from 2024 to 2025. 

Infested parks and sports facilities closed

Oak processionary moths are gray-brown moths. Their caterpillars have tiny stinging hairs that contain a toxin which, upon contact, can cause skin irritation accompanied by severe itching and hives. Eye irritation, coughing, or asthma-like symptoms may also occur. As a result, parks and sports facilities in many areas were closed in the spring and summer.

Various measures to combat oak processionary moth

There are various measures to combat the oak processionary moth, depending on whether the infestation is severe or mild. According to the Plant Protection Agency, mechanical measures such as vacuuming, sealing off affected areas, and treatment with hot water or hot foam are generally sufficient for mild infestations. In cases of severe, multi-year infestations in sensitive areas where many people gather, spraying biocides may be considered. In such cases, regulations regarding nature conservation, species protection, landscape preservation, and water quality must be observed, according to the Plant Protection Agency.

Joint strategy expected to be in place by end of year

It is also possible to release nematodes - that is, roundworms - which penetrate the caterpillars and kill them. In addition, there are natural predators of the oak processionary moth, such as certain flies, wasps, and beetles, as well as some bird species that can be specifically encouraged through the use of nesting boxes. The joint strategy of the Senate and the districts against the oak processionary moth is currently being revised. It is expected to be available by the end of the year.