Emergence of Basil Downy Mildew in India: need more domestic vigilance to combat spread of Peronospora belbahrii

Downy mildew, caused by Peronospora belbahrii Thines, is the most destructive disease of sweet basil (Ocimum basilicum L.) in all basil producing countries of the world. In India, the disease appeared suddenly in 2019 in greenhouse farms of Simply Fresh Pvt. Ltd., Hyderabad where sweet basil is produced commercially using the seeds imported from Germany. The morphological and molecular characterization of the pathogen confirmed the identity of the pathogen as Peronospora belbahrii. The seed sample when subjected to seed health tests at the notified Seed Testing Laboratory of Seed Research and Technology Centre (SRTC), PJTSAU revealed the seed to seedling transmission of pathogen in sweet basil. The seeds stored for a period of two years under refrigerated conditions (4 °C) also produced infected seedlings under controlled conditions. As the disease is new to India, strict quarantine measures are to be imposed to mitigate the further spread of the disease to new areas in the country.