leaf spot symptoms caused by downy mildew.

wildflower vegetable deciduous produce flower garden autumn plant green shrub fruit petal leaf tree herb food soil background texture nature spring leaf leaves agriculture plant science environment vegetable organic gardening ecology botany disease infection biology cucumber health care horticulture fungus microbiology cultivation fungi pathogen macro pathology fungal fungicide powdery mildew cucumber diseased downy downy false fungal plasmopara mildew pseudoperonospora pseudoperonospora cubensis single spread target spot