Oak processionary caterpillar numbers surge sevenfold in Luxembourg city

Luxembourg city has removed 180 oak processionary moth nests this year, a sevenfold increase from the 25 nests cleared in 2025, according to Jimmy Gales of the city’s park administration speaking to RTL Luxembourg.

The caterpillars, known for their irritating hairs that cause rashes and itching, have also forced closures in Denmark, including playgrounds, a nursery, and a recycling station in Odense.

To combat the infestation, several Luxembourg municipalities will install nest boxes to attract tits, one of the few bird species that eat the caterpillars. Heikko Buch-Illing, director of the Naturama natural history museum, confirms that tits can safely consume the caterpillars without harm from their toxic hairs, as the birds’ feathers prevent the hairs from penetrating their skin.

While the approach could be adopted in Denmark, Buch-Illing notes that tits do not primarily feed on oak processionary caterpillars, so the impact may be limited depending on the scale of the infestation. Bats and the torntit are also natural predators of the moth.

Danish Minister for Nature and Animal Welfare Christian Rabjerg Madsen (S) has announced plans to coordinate a national response involving relevant authorities.