Following the commodity risk assessments of Acer spp., Malus spp. and Prunus spp. plants for planting from the United Kingdom (UK), in which Eulecanium excrescens (Ferris) (Hemiptera: Coccidae) was identified as a pest of possible concern, the European Commission requested the EFSA Panel on Plant Health to conduct a pest categorisation of E. excrescens for the territory of the European Union (EU). E. excrescens, commonly known as excrescent or wisteria scale, is a polyphagous pest, primarily feeding on deciduous orchard and ornamental trees. It is present in the USA, China (Sichuan) and in the UK. It is not present in the EU. E. excrescens can be found on leaves and woody parts of the host plants. The pest completes one generation per year and overwinters on twigs as nymphs. E. excrescens is reported as harmful in Oregon (USA) on hazelnut, and in China on fruit trees, without details on the magnitude of yield and quality losses. In the UK, serious damage was reported on wisteria plants in 2001, but since then there have been no further reports of damage. The magnitude of impact in the EU is therefore uncertain. Phytosanitary measures are available to reduce the likelihood of entry. All criteria assessed by EFSA for consideration as a potential quarantine pest are met.
