An illustrated guide to distinguish emerald ash borer (Agrilus planipennis) from its congeners in Europe

Emerald ash borer (EAB) Agrilus planipennis is native to East Asia and has recently become a devastating alien pest of ash trees in North America and European Russia. There is no doubt that the pest will spread to other European countries. Early detection and identification of this damaging pest is crucial for minimizing its potential negative economic and ecological impacts. There are about 87 species of the genus Agrilus in Europe, but there are no guides for identification, that include Agrilus planipennis and native species. We present here the first guide to distinguish emerald ash borer from similar native European Agrilus species based on easily detectible external morphological characters suitable for use by non-taxonomists. The main diagnostic characters of EAB adults are: large size (12–15 mm), head and pronotal disc deeply impressed, pronotal sides converging toward anterior margin, elytra mostly brightly emerald, without tomentose spots, pygidium bearing apical process. The main diagnostic character of EAB larvae is the bell-shaped abdominal segments 1–7.