Pome and stone fruit trees as possible reservoir hosts for Phaeoacremonium spp., the causal agents of grapevine esca disease, in Iran.

Phaeoacremoniumspp. are known as the main Hyphomycetes associated with esca disease symptoms on grapevines worldwide. The role of other woody hosts in proximity of vineyards as a possible inoculum source for the causal agents of grapevine esca disease mainly remains unknown. The aim of this study was to investigate the occurrence ofPhaeoacremoniumspp. on pome and stone fruit with trunk diseases symptoms in northwestern parts of Iran. For this purpose, wood trees samples were collected from apple and apricot trees with trunk disease symptoms. Isolation was made using routine plant pathology methods. Based on the morphological and cultural characteristics,Phaeoacremonium aleophilumandPhaeoacremonium iranianumwere identified from apple trees andP. aleophilumwas recovered from apricot trees with trunk disease symptoms. A phylogenetic analysis based on the sequence data fromβ-tubulingene further confirmed the identity of the species asP. aleophilumandP. iranianum. The results of inoculation assay on detached shoots of apples revealed thatP. iranianumis pathogenic on apple. Our results also showed thatP. aleophilumisolates from different hosts (apple, apricot and grapevine) were pathogenic on apple and induced wood discolouration on apple stems. There was no significant difference on the length of lesions induced in relation to the origin of theP. aleophilumisolates. This study is the first report on the occurrence ofP. iranianumon apple trees with trunk disease symptoms worldwide and the first report on the occurrence ofP. aleophilumon apple and apricot in Iran. [ABSTRACT FROM PUBLISHER]