Fungi associated with canker diseases on olive in Istria (Croatia)

A survey in olive orchards in Istria (Croatia) was carried out from 2016 to 2018 to investigate pathogens potentially associated with olive decline and dieback. In nine orchards, canker-like symptoms were recorded on olive trunks and branches. Six fungal species were isolated from cankers: Geosmithia sp., Diaporthe sp., Diatrype stigma , Diplodia seriata , Neofusicoccum parvum , and Pseudophaeomoniella oleae . Pathogenicity tests were conducted in a greenhouse, on branches of 4-year-old local cultivar ‘Buza’. Eight months after branch inoculation, D. seriata showed to be the most aggressive, causing an average of 67 mm long lesion. N. parvum caused 31 mm long lesion, while Diaporthe sp. showed only weak aggressiveness, causing 3 mm long lesion. Diatrype stigma , P. oleae and Geosmithia sp. did not cause any symptoms on inoculated plants. This is the first report of Neofusicoccum parvum and Diaporthe sp. as pathogens on olive in Istria (Croatia).