Oak processionary moth

Keep your distance and never touch caterpillars or nests!


Oak processionary

Thaumetopoea processionea

Keep your distance and do not touch caterpillars or nests under any circumstances!

EPS - Oak processionary moth

Caterpillars with stinging hairs

Further information: Julius Kühn Institute

Danger to humans from caterpillar hairs (clear-cutting of oaks)

The stinging hairs contain a protein toxin (stinging nettle toxin thaumetopoein) that can trigger allergic reactions.

  • Caterpillar hair dermatitis (severe itching, inflammation)
  • Inflammation of the conjunctiva
  • Inflammation of the upper airways
  • General symptoms (dizziness, fever)
Favourable weather and air currents can transport the stinging hairs over long distances and deposit them on undergrowth, foliage, clothing, shoes, etc.

If you see the caterpillars or their nests on oak trees that are on public land, please pass the information on to your town's public order office immediately.

Contact us if your private trees are affected.



The eggs are laid around August, well camouflaged (almost invisible) on one to two year old sunny branches. The young caterpillars overwinter there until the next spring.

The caterpillars hatch from the beginning of April and pupate in July. The heavily hairy animals are initially yellowish-brown, later bluish-black in colour and 4 cm long. During this time, they build their typical webs on the trunk and in branches. From there, they start their processionary raids and can completely strip oaks bare. Only the midrib of the leaves remains.

After the moths have hatched, the webs with moulting remains, faeces and active stinging hairs remain. The danger thus remains for years.


The removal of the caterpillar nests is carried out with fully enclosed protective suits and respiratory protection. Suction is only permitted with approved H-class suction units ("asbestos", according to TRGS 519), manual collection after fixation is also possible. The technique to be used varies with the use of the aerial work platform or rope climbing technique.

EPS material and protective suits must be transported away in airtight containers and disposed of in a waste incineration plant.

Decontaminate used tools, vehicles, etc. with water.

EPS suction