downy mildew of grape

agriculture and berries biology blight closeup control danger disease diseased downy farming flower fungi fungicide fungual fungus garden gardening grape green grow home infection infest infestation leaf macro microorganism mildew mold mould nature parasite pathogen pathology pest pesticide photo phytopathology plague plant plasmopara problem protection pustules repellent science shows spores spot summer symptoms terrace vine vinifera viticola vitis