The lepidopteran Orgyia leucostigma is endemic in Canada and the USA. So far, it does not occur in Germany. There are individual unconfirmed notifications from England. The species did not establish in the rest of Europe. At present, it is listed neither in the Annexes of Directive 2000/29/EC nor by EPPO. Orgyia leucostigma infests a very broad range of host plants including commercially used crops in forests and agriculture and in public green spaces. Due to suitable climatic conditions in Germany and in large areas in Europe, from the northern areas of Spain and Greece to Sweden and Finland, it is assumed that the pest is capable to establish outdoors. Due to its damage potential for a multitude of host plants, Orgyia leucostigma presents a significant phytosanitary risk for Germany and other EU-Member States. Based on this risk analysis it is assumed that Orgyia leucostigma is able to establish in Germany and other Member States and to cause significant damage. Thus measures against the release of this potential quarantine pest should be met according to § 4a of the Plant Inspection Order.