Oak processionary moth spreads across Denmark

The oak processionary moth, known colloquially as the “larva from hell,” is spreading in Denmark, with multiple reports on Funen, Jutland, and Amager, state broadcaster DR reports.

The caterpillars carry microscopic hairs that can cause itching, rashes, and in rare cases, breathing difficulties.

Thomas Pape, an insect researcher and professor at the Natural History Museum of Denmark, advises homeowners with oak trees to monitor their trunks and thick branches for nests of the pest. If found, the discovery should be reported to local authorities. The critical period for vigilance is May through July, when larvae are present.

Pape also recommends checking neighboring oak trees, as nearby infestations increase the risk of spread.

Natural predators

Encouraging natural predators, such as great tits and blue tits, can help control the moth population. Installing nest boxes, bird feeders, or bird baths may attract these birds, which feed on the caterpillars. The professor notes that small birds are unaffected by the caterpillars’ irritating hairs.

Do not fell oak trees

While felling oak trees might seem like a solution, Pape strongly advises against it. Oak trees are vital to the ecosystem, and removing them will not solve the problem, as the moth will persist in other oaks. He acknowledges the need for action in severely affected areas but emphasizes that the response should not involve cutting down trees.

“We must learn to live with it, as we do with nettles and other hazards in nature,” Pape said.