Because of the health nuisance, a lot of effort was put into prevention. For example, by spraying trees with bacteria and nematodes, which are small soil worms. “That cost a lot, but it has been effective,” says Van Vliet. this year the caterpillars also had a bad spring because of the weather. “It was very hot at first, then very cold.”
Where did the oak processionary caterpillar go? ‘Fighting costs something, but it is effective’
