# Pest categorisation of Eulecanium excrescens

## TL;DR

This paper assesses the risk of Eulecanium excrescens, a scale insect, becoming a quarantine pest in the EU due to its potential to harm orchard and ornamental trees.

## Contribution

The paper provides a pest categorisation of Eulecanium excrescens for the EU, evaluating its potential as a quarantine pest.

## Key findings

- Eulecanium excrescens is not present in the EU but is found in the USA, China, and the UK.
- The pest is harmful to hazelnut and fruit trees, though the extent of damage is unclear.
- Phytosanitary measures can reduce the risk of its introduction into the EU.

## Abstract

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.