Potential host range of Anthostoma decipiens and Endothiella sp., agents of hornbeam blight.

Abstract

Reports of decline and blight of hornbeam (Carpinus betulus L.) in Italy and surrounding countries have recently increased. Two fungi were constantly isolated from cortical cankers and identified as Anthostoma decipiens (Cytospora decipiens) and Endothiella sp. A. decipiens was also found on dead branches of species other than hornbeam. The pathogenicity of A. decipiens and Endothiella sp. was assayed on plant species taxonomically or ecologically related to hornbeam: Acer campestre, Alnus glutinosa, Betula pendula, Castanea sativa, Corylus avellana, Fagus sylvatica, Ostrya carpinifolia, Populus nigra and Quercus robur. The fungi were inoculated in bark wounds and cankers appeared after 30 days on the most susceptible species. Anthostoma decipiens infected all species except for Acer campestre and Populus nigra, whereas Endothiella sp. showed a narrower host range, infecting three out of nine species, i.e. Corylus avellana, Ostrya carpinifolia and Alnus glutinosa. These latter species were also susceptible to Anthostoma decipiens. The inoculated pathogens were re-isolated from the species on which cankers developed. Anthostoma decipiens and Endothiella sp. were pathogenic to a broad host range, therefore tree species that share the same ecosystem with Carpinus betulus may be at risk of infection, both in forests and in urban and sub-urban green areas.