Occurrence of Erysiphe friesii var. dahurica on purple buckthorn (Rhamnus purpurea) from Pakistan

Leaves of purple buckthorn observed with powdery mildew symptoms were collected from the district Abbottabad, Khyber-Pakhtunkhwa, Pakistan during field tours from August to October between 2017 and 2021. Morpho-anatomical features and molecular phylogenetic analysis were used to identify the causal agent as Erysiphe friesii var. dahurica. Pathogenicity was confirmed on healthy leaves of Rhamnus purpurea in a glasshouse at 25 degrees C with 75 to 80% humidity and after inoculation, white powdery colonies appeared after 7 to 10 days. The fungal colonies were checked for the confirmation of pathogen. Erysiphe friesii var. dahurica on R. purpurea is being described here as a new record for Pakistan and Rhamnus purpurea is a new host, reported for the first time.

Automated summary

Leaves of purple buckthorn showing powdery mildew symptoms were collected from Pakistan and identified as Erysiphe friesii var. dahurica using morpho-anatomical features and molecular phylogenetic analysis. Pathogenicity was confirmed by inoculating healthy leaves of Rhamnus purpurea, resulting in the appearance of white powdery colonies after 7-10 days. This is the first report of Erysiphe friesii var. dahurica infecting Rhamnus purpurea in Pakistan.