Overview
- Local authorities in Germany and Denmark reported rising infestations in early July 2026 and have cordoned off affected trees, closed small public areas and posted warning signs to protect visitors.
- Municipal crews and specialist firms are using mechanical methods such as vacuuming and lift-assisted removal to clear nests, and officials say broad chemical spraying is not being planned.
- The caterpillar hairs contain the protein thaumetopoein and can break off, travel on air and cause itching, rashes, eye irritation and respiratory problems, with hairs remaining hazardous in nests and debris for months or years.
- Residents, including medically vulnerable people who report severe reactions, are asking councils for faster action or subsidies to pay private firms and local councils say capacity and cost limit how many sites they can treat.
- Authorities are weighing complementary tactics such as ecological adhesives and measures to attract natural predators like tits and parasitic wasps while continuing active monitoring and targeted removal at high‑use sites.