Resistance of olive cultivars to Botryosphaeria dothidea, causal agent of olive fruit rot in Montenegro

Fruit rot has caused severe damage in olive orchards in Montenegro in recent years. Symptoms of the disease in commercial orchards include necrotic, depressed and clearly delimited spots on fruit. Identity of fungal isolates from infected fruit was confirmed by morphological and molecular evidence as Botryosphaeria dothidea. Pathogenicity was confirmed by fulfillment of Koch's postulates. Seventeen olive cultivars were assessed for susceptibility to the causal agent. Two native cultivars, Crnjaka and Gloginja, were highly resistant, whereas the most widely grown domestic variety, Žutica, was susceptible. Introduced cultivars Pendolino and Cassanesse were highly resistant and Giarraffa and Ascolana tenera were the most susceptible olive cultivars. This report is the first comparison of cultivar resistance to olive fruit rot in the Balkan region, and the first assessment of resistance in olive cultivars indigenous to this region.