Emerald Ash Borer Approaches the Borders of the European Union and Kazakhstan and Is Confirmed to Infest European Ash

Abstract

Emerald ash borer (EAB), Agrilus planipennis, native to East Asia, is an invasive pest of ash in North America and European Russia. This quarantine species is a threat to ash trees all over Europe. Survey in ten provinces of European Russia in 2019–2020 showed that EAB had spread faster and farther than was previously thought. The new infested sites were first detected in St. Petersburg (110–120 km from the EU border: Estonia, Finland) and Astrakhan Province (50 km from the Kazakhstan border). The current range of EAB in Europe includes Luhansk Province of Ukraine and 18 provinces of Russia: Astrakhan, Belgorod, Bryansk, Kaluga, Kursk, Lipetsk, Moscow, Orel, Ryazan, Smolensk, St. Petersburg, Tambov, Tula, Tver, Vladimir, Volgograd, Voronezh, and Yaroslavl. Within these, only seven quarantine phytosanitary zones in five provinces are declared by the National Plant Protection Organization of Russia. EAB was not found in the regions along the Middle Volga: Mari El, Chuvash and Tatarstan republics, Nizhny Novgorod, Samara and Saratov provinces. The infested sites in St. Petersburg and in the Lower Volga basin are range enclaves separated from the core invasion range by 470 and 370 km, correspondingly. It is possible that new enclaves can appear in the cities of Eastern Europe and Kazakhstan far from the current known range. All previously known infestations in European Russia were in green ash (Fraxinus pennsylvanica), which was introduced from North America, and individual trees of European ash (F. excelsior). A first confirmed case of mass decline of several thousand of EAB-infested European ash trees in Moscow province is provided. Therefore, there is no more doubt that under certain conditions EAB can seriously damage native ash trees in European forests.