First report of powdery mildew of pomegranate (Punica granatum) caused by Erysiphe punicae in India

Pomegranate (Punica granatum L.) cultivation was first practiced in eastern nations like India and the Mediterranean regions. India stands first in pomegranate production and cultivated area in the world. During the year 2021, powdery mildew symptoms were observed on pomegranate plants of the cultivar G-37 and P-23 at the research farm (Dhanda) of ICAR-IARI Regional Station, Amartara Cottage, Shimla, 171,004 Himachal Pradesh, India. The research farm comes under the southwestern ranges of the Himalayas. The disease incidence was recorded to be 40% in both cultivars. The premature leaves and buds were covered in the dense, white mycelium and conidial mass patches that were powdery in appearance. Microscopic examination revealed the presence of enormous ellipsoid conidium structures associated with the diseased specimen. The conidiophores foot-cells were slightly tapered to straight measuring 70-190 x 4-7 mu m. Conidia was hyaline, 37-27 x 14-11 mu m (average 31.96 x 12.93 mu m), however, chasmothecia could not be observed in the specimen. The molecular identification based on internal transcribed spacer region primers disclosed the fungus identity as Erysiphe punicae. The pathogenicity test was subsequently performed to prove the Koch postulates on the initially identified host cultivar P-23. To the best of our knowledge, this is the first report of powdery mildew of pomegranate caused by Erysiphe punicae in India.

Automated summary

Powdery mildew caused by Erysiphe punicae was reported for the first time in pomegranate plants in India. The disease was identified through microscopic examination and molecular identification. This finding is important for pomegranate cultivation in India.