Morphological characterization of <em>Plasmopara viticola</em>, the inciting agent of grapes downy mildew

Abstract

Grapes downy mildew is incited by the most destructive pathogen called P. viticola is a major bottleneck for grapevine production. The morphological and ultra structural analysis of the pathogen plays a significant role in order to take precautionary management strategies. For morphometric analysis the downy mildew infected leaf samples were collected from eight different locations in Coimbatore and Theni districts. The collected samples were subjected to morphoplogical analysis under light microscope at 40 X magnification. The length and breadth of the sporangia vary from 19.94 -22.73 µm and 14.58-17.69 µm. The scanning electron microscopic analysis of P. viticola shows the developmental stages of the pathogen on the host leaf surface. The Pathogenicity of the pathogen was confirmed through detached leaf assay. The characteristic sporulation of the fungus was observed at 7 th day after post inoculation.