Bottlebrush and Myrtle twig canker caused by Neopestalotiopsis species: an emerging canker-causing group of fungi in Italy

Abstract

Pestalotioid fungi were isolated in pure culture from symptomatic plants of Callistemon laevis, C. viminalis, Luma apiculata (marketed as “Myrtus luma”), Myrtus communis subsp. tarentina, and M. communis var. microphylla (M. communis ’Microphylla’), showing twig canker, dieback and defoliation. The isolates were identified to species by ITS, tef1 and tub2 sequences, which revealed the presence of six species of Neopestalotiopsis (N. camelliae-oleiferae, N. hispanica, N. iberica, N. rosae, N. rosicola, and N. zakeelii) and one species of Pestalotiopsis (P. biciliata). While most species were isolated only once or twice, the majority of isolates belonged to N. rosae (13) and N. hispanica (8). Pathogenicity was investigated by pathogenicity tests on all hosts, which confirmed the pathogenicity of all Neopestalotiopsis species on at least some of the hosts tested, while P. biciliata did not cause any disease symptoms. Neopestalotiopsis hispanica and N. rosae caused symptoms in all hosts of the present study, while the other Neopestalotiopsis species tested showed no symptoms on Luma apiculata.