Taxonomic studies of powdery mildew fungi infecting almond and walnut in the Northwestern Himalayan region of India

Powdery mildew is a significant fungal disease that affects the wide range of crops including nut fruits. Given their economic importance, the accurate identification of the causal fungus is essential for devising an effective disease management program. In a recent study, seventy-five powdery mildew samples were collected throughout the Kashmir valley of Jammu and Kashmir, India from two nut fruits crops namely almond (Prunus amygdalus) and walnut (Juglans regia L.). These samples were analyzed to identify the associated fungi. The fungi were first characterized morphologically followed by molecular characterization using the ribosomal DNA internal transcribed spacer (ITS) region. The study identified three species belonging to three different genera within the Erysiphaceae family viz., Podosphaera pannosa on almond, Phyllactinia juglandis under field and Erysiphe juglandis under greenhouse conditions on walnut. Notably, Podosphaera pannosa on almond, Erysiphe juglandis (in greenhouse) and Phyllactinia juglandis (in field conditions) on walnut represent the first reports from Jammu and Kashmir, India. This research highlights the diversity of powdery mildew pathogens affecting nut crops in the region and underscores the importance of accurate disease or pathogen identification for the effective management of the disease.