Incidence, severity and causal fungal species of Mycosphaerella and Teratosphaeria diseases in Eucalyptus stands in Galicia (NW Spain)

• Most eucalypt stands in NW Spain were mainly affected by Teratosphaeria Diseases (TD).
• TD and MD severity was high in Eucalyptus globulus plantations.
• The most prevalent species was Teratosphaeria nubilosa, followed by Teratosphaeria parva and Teratosphaeria molleriana.
• These three fungal species were responsible for the highest levels of disease severity.
• New records of eucalypt host-fungal pathogen association are presented.

The incidence and diversity of fungal species causing Mycosphaerella Diseases (MD) and Teratosphaeria Diseases (TD), and the disease severity, were studied in 190 stands of Eucalyptus globulus, 17 of Eucalyptus nitens, 3 of Eucalyptus viminalis and 1 of Eucalyptus obliqua in NW Spain. Results showed that MD and especially TD were present in practically all E. globulus plantations, in many of them with a high severity, suggesting they might be suffering important wood yield reductions, and extended with low severity to E. nitens, E. viminalis and E. obliqua stands. Eleven species were identified, namely Mycosphaerella aurantia, Mycosphaerella madeirae, Mycosphaerella marksii, Pseudocercospora pseudoeucalyptorum, Teratosphaeria africana, Teratosphaeria molleriana, Teratosphaeria nubilosa, Teratosphaeria parva, Teratosphaeria readeriellophora, Uwebraunia commune and Uwebraunia dekkeri.All species were found in juvenile foliage, and most also in adult leaves, in E. globulus stands. Less fungal diversity was recorded for E. nitens, E. obliqua and E. viminalis plantations. T. africana on E. globulus is a new record for Spain. M. aurantia on E. globulus, P. pseudoeucalyptorum and U. commune on E. nitens, M. madeirae and T. molleriana on E. obliqua, and T. nubilosa and T. parva on E. viminalis are first records in Europe.The most frequently isolated species was T. nubilosa, followed by T. parva and T. molleriana. These three fungi were responsible for the highest levels of disease severity.