Recognise oak processionary moths

Oak processionary moth?

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Oak processionary moth

(Thaumetopoea Processionea)

Oak moth


  • The oak processionary moth is a rather inconspicuous, grey-brown butterfly.
  • It is active from mid-July to early September.
  • Its wingspan is 25 to 30 mm.
  • The caterpillars of the oak processionary moth have a dark, broad backline with velvety hairy fields and red-brown, long-haired warts.


  • The eggs (100 to 200) of the oak processionary moth overwinter in egg clutches on the trunk. They are about 1 mm tall and white.
  • In April and May, the caterpillars hatch and wander in the typical multi-row processions.
  • The larvae pupate between the end of June and the beginning of July and finally hatch out of the nests as butterflies in late July to early August.

Way of life

  • The caterpillars of the oak processionary moth are considered pests because they cause clearing or baldness.
  • They live in large colonies and go through six stages. From the third stage onwards, they wear stinging hairs, which can cause toxic and allergic reactions in humans.
  • The oak processionary moth is at risk all year round, as older web and moulting residues also contaminate the surrounding areas. Thus the allergenic effect of the stinging hair continues for months and even years.