First report of Botryosphaeria dothidea causing dieback disease on apricot trees in Korea

Phylogenetic analysis confirmed that fungal isolates clustered within the B. dothidea species.Pathogenicity tests was performed using mycelia (PDA plug) on three years old apricot cultivar 'Harcot'.Fungal isolates were inoculated on the wounded site of 10 twigs for each of three different trees growing at the National Institute of Horticulture and Herbal Science trial farm.Apricot twigs were mock inoculated with sterile PDA plugs as a control.Seven days post-inoculation, the inoculated sites had turned dark brown, indicating fungal isolates are pathogenic to apricot.No symptoms were observed on the control twigs.The re-identification results reveal that the fungi's morphology is indistinguishable to the original isolate, while their molecular marker sequences are 100% identical, thus fulfilling Koch's postulates.An accurate identification of the causal agent is needed to implement appropriate disease management strategies to minimize its impact on the apricot industry.To our knowledge, this is the first report of dieback disease caused by B. dothidea on apricot in Korea.