Report nests of the oak processionary caterpillar

May 23, 2023
The offense is usually the best defense: suck up, deploy enemies and report. All because the oak processionary caterpillar can cause a lot of itching.

Oak processionary caterpillars like to eat oak leaves, so in that respect they imagine themselves in Valhalla. At night they go out to eat in the tree in long rows. In procession. Hence the name. Groups of processionary caterpillars can eat a tree completely bare. And above all: about 700.000 stinging hairs per caterpillar! You will get complaints from those fire hairs. 

What do you get?

Fire hairs of the processionary caterpillar cause complaints. Fire hairs are also spread by the wind. Even if you don't touch a caterpillar, you can still get complaints. The same goes for animals. Stinging hairs easily penetrate the skin, eyes and airways with their barbs. You may experience itching, red and painful skin rashes and irritated airways and eyes. If you have complaints, prevent the hairs from spreading further over your body. Remove the hairs of the caterpillar on your skin, for example with adhesive tape, and rinse your skin and eyes with lukewarm water. Clothing with stinging hairs is best washed at 60ÂșC. If the complaints are serious, go to the doctor. 


  • Recognize the caterpillar! And then keep your distance. How do you recognize the oak processionary caterpillar? Oak processionary caterpillars make white woolly nests in trunks and branches of the oak tree. They are dense webs of molting skins, full of stinging hairs and excrement
  • If you visit an area where the processionary caterpillar is located, cover your neck, arms and legs as much as possible
  • You can place tit boxes in your own garden. These are for sale in, for example, garden centres. Or plant umbelliferous plants and flowers. Insects that hunt the oak processionary caterpillar like that

To know

  • The municipality checks the oaks in Hilversum in the public space
  • We remove found nests as soon as possible by vacuuming them
  • Places where people are for a longer period of time have priority for checking and removing the nests. Think of schools, playgrounds, cemeteries and important cycling and walking paths
  • You must have a nest removed on your own property. Have this done by a pest control company or gardener (gardener or gardener)
  • We try to get ahead of the oak processionary caterpillar by giving space to their natural enemies such as insects, birds and bats. We do this, among other things, by mowing less and putting up nest and bat boxes

Report a litter

Report a nest of the oak processionary caterpillar on the map. The map can be found on the page 'report oak processionary caterpillar nest'. The map shows all the oaks in Hilversum. If the tree in which you see a nest has not yet been reported, click on the tree on the map. 

Oak processionary caterpillar in the tree