The oak processionary moth

The oak processionary moth. Background knowledge and recommended action

Simon Blaser, Mario Guetg, Martin Bader, Beat Wermelinger, Stefan Studhalter, Valentin Queloz

WSL Fact sheet 71
Publishing year:
8 Pages

Blaser S., Guetg M., Bader M., Wermelinger B., Studhalter S., Queloz V. (2022) The oak processionary moth. Background knowledge and recommended action. WSL Fact sheet 71. Birmensdorf: Swiss Federal Institute WSL.8 p.

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Background knowledge and recommended action

The oak processionary moth is a moth native to Europe that develops mainly on oak trees. In Switzerland, it is mainly found in western and north-western regions, and on the southern side of the Alps. After hatching, its caterpillars feed in gregarious clusters on the leaves of oak trees, and large populations can lead to the complete defoliation of infested trees. The oak processionary moth attracts particular attention because the urticating (stinging) hairs of its caterpillars can cause allergic reactions in humans and animals.


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The Merkblatt für die Praxis (ISSN 1422-2876, digital ISSN 2296-4428) summarises key findings from WSL research and provides guidelines for best practice. The series is aimed at forestry and nature conservation groups, authorities, schools and interested laypersons.

French editions are published in the series Notice pour la practique (ISSN 2813-6071). Italian and English editions appear occasionally in the series Notizie per la pratica (ISSN 1422-2914) and WSL Fact Sheet (ISSN 2624-8069).