Annual Research & Review in Biology,
New plantations of Olive tree in northern Iran are usually being severely affected by wilt or dieback and death. To determine the etiology of this problem, a study was carried out in samples of affected young trees collected in Golestan, Zanjan, Gilan and Khorasan provinces, the north of Iran during 2004-2009. Fungi that cause olive disease or associated with stem cuttings are listed. From this list Verticillium dahliae and Fusicladium oleagineum were the most common on a wide range area and on all cultivated cultivars. Several fungi were isolated from seedling rotted roots and some recorded associated with stem cuttings. Other fungal species associated with death of young olive trees in the field or in the nurseries, including Botrytis cinerea, Colletotrichum acutatum, Colletotrichum gloeosporioides, Fusarium solani, Macrophomina phaseolina, Neoscytalidium dimidiatum, Phytophthora megasperma, Phytophthora nicotiana, Pythium aphanidermatum, Rhizoctonia solani and some stem decay fungi such as species of Ascochyta, Alternaria, Cephalosporium, Chaetomium, Cladosporium, Diplococcium, Diplodia, Nigrospora, Sphaeropsis, Stemphyllium and Ulocladium. As the fungal pathogen can affect olive production, these findings are potentially important to the future olive industry in northern Iran.