Identification and Morph-metric Characterization of Powdery Mildew Infecting Diverse Host Plants of Southern Gujarat, India

Powdery mildews are obligate biotrophic fungal pathogens that are responsible for disease on a wide range of host plants with white powdery patches on plant parts. An exhaustive survey in the Navsari region of south Gujarat was carried out to identify white powdery/floury circular to irregular spots, specks or patches either on the upper surface or lower surface or both the surface of the leaves. These powdery mildew symptoms were observed on leaves, stems and pods/fruits on 39 hosts of 22 families. For precise identification of the pathogen the morphological characteristics included mycelium, length and breadth of conidia, conidiophores, appressorium, conidial germ tubes foot cell and fibrosin bodies. Majorly the genera like Erysiphe, Golovinomyces, Leveillula, Oidium, Phyllactinia, Podosphaera, Micro-oidium and Sphaerotheca were found on different hosts in this region. The maximum number of hosts were infected by the genus Oidium followed by Erysiphe. The highest percent disease incidence was observed on the asthma plant, black gram, green gram and wild poinsettia between 75-100 per cent out of all the hosts.