Corsica. Parasitic caterpillars have destroyed 25,000 hectares of forests. “They seem to have been devoured by flames”

Corsica. There is a parasite alarm in the forests of Bonaparte Island. In mid-June, the caterpillars of the odd-leaf gypsy moth (lymantria dispar) have already devoured 20,000 hectares of forest, in addition to the 5,000 destroyed last summer. Well known on the island, the phenomenon, aggravated by the progressive increase in average temperatures and the length of the hot season, is causing an almost hellish effect in the affected villages, where everything seems to have been burned. "For the public authorities it is not serious, but for us it is a catastrophe," Jean-Marie Casamarta, 49, owner of the "Zella" guesthouse in Guitera-les-Bains, a village renowned for its hot sulphurous waters, told the Agence France Presse: "I feel like in the Lord of the Rings, when they kill ten killer whales and a hundred arrive!"

Because nothing works: "I've killed thousands of them, raked them, burned them, drowned them, used organic insecticides and called a specialist company twice, for a total of 1,700 euros, which saved the season, but they keep coming back," he explains.

Like forest fires

Isolated in the forest, the house is the heart of the family farm, among 150 pigs, a dairy, centuries-old oak trees and, everywhere, hairy caterpillars a few centimetres long - brughi , in Corsican - which have transformed the wooded hills, making them grey-brown, as if charred.

"The first thing I thought was that the valley had burned, like 40 years ago," says Ernest Albucker, a 70-year-old vacationing in Corsica, the most forested Mediterranean island with 550,000 hectares of forest, or 58 percent of the territory, according to the National Forestry Office.

“The streets are brown,” stained with thousands of squashed caterpillars, says Serkan Aksin, a 47-year-old Welsh motorcyclist from Cardiff, who is surprised by this unusual monochrome and “pungent-smelling” landscape. Visually striking, this invasion remains a well-known natural phenomenon in the far south of the island, where it lasts from late April to July, when the caterpillars become butterflies.

Prefecture: “Four-year cycles”

The prefecture of Corsica tries to reassure, specifying that "the infestation cycles last from two to four years, with a latency period of six to twelve years between each cycle". "The caterpillar populations will regulate themselves naturally from mid-June", with "the reduction of food resources and the increase of predators, especially birds", explains the prefecture, attributing the extent of the phenomenon "to the recent high temperatures" and stressing that, although "it necessarily weakens the affected trees", it does not kill them.

This is the second year of the epidemic, which, in 2024, affected 5,000 hectares of forest. This year we are already at 20,000 hectares, as explained by Orso Cerati, one of the six island observers of the Department of Forest Health (DSF). "We hear them eating among the leaves," the expert emphasized.

“They are everywhere, even in fireplaces”

"Psychologically, it's tough, it's a daily battle and we've lost customers. Some hikers have cancelled," Casamarta said, "angry with the authorities." Unlike its cousin the processionary, the gypsy moth caterpillar "does not have stinging hairs," the prefecture noted, although several villagers, including Casamarta, claim, with photos to back up their claims, that they have developed red spots.

"It's unbearable. Since six in the morning we've been sweeping the terraces and facades. There's it everywhere, even in the chimney. We live in the house, we have no choice," says Juliette Giannotti, a 54-year-old postman, in her home in Guitera. "In 50 years, I've never seen anything like it."

From mid-July, the devoured trees, mainly oaks, will begin to sprout again, Cerati concludes. But this is energy-intensive and will reduce acorn production.