Oak processionary, treatment for this caterpillar

Oak processionary caterpillars writhing across oak tree bark in droves.

This well-known oak tree parasite is a caterpillar that devours the leaves, until it gathers to form a nest that looks like a spider web.

The scientific name is Thaumetopoea processionea and it’s also called oak processionary moth.

Solution to treat against oak processionary

There is practically no available effective treatment. The only solution is to prevent caterpillars from spreading to other oak trees.

  • Locate and destroy nests which are a wispy white color, as if made from spider webs.
  • In some areas such as England, authorities prefer that you report the nests to the local forestry bureau. They will dispatch a team to rid you of the nest.

To preserve and protect surrounding trees, cut off branches where nests form and destroy them.

Smart tip about oak processionary

Take great care when cutting caterpillar-infested branches off. Indeed, hairs from these hairy caterpillars are extremely itchy, not only for you but also for dogs, cats, and any other pet living in your house!

Oak processionary munching on an oak leaf.

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Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Colony of oak processionary by Jacqueline under Pixabay license
Oak caterpillar on leaf by Andreas März under © CC BY 2.0