Downy Mildew

Downey mildew Common name Downey mildew Causal agent Downey mildew is caused by a type of water mold belonging to the family Peronosporaceae. Each species of water mold attacks a specific type of plant, including vegetables, fruits, and flowers. Scientific name Peronospora parasitica Peronospora effusa Pseudoperonospora cubensis Peronospora belbahrii Symptoms & Signs The symptoms vary depending on the plant species. The initial symptoms include yellow spots on the upper side of the leaves that soon turn brown. A few species also produce white or purple short hairs on the underside of the leaves. Since the dead leaf tissue is unable to photosynthesize, the leaf eventually dies and falls off. Transmission It can transfer to other healthy plants through wind, water, infected tools, and hands. Cool, humid conditions favor the spread of Downey mildew. Time of concern Early spring to late summer Common hosts Basil Squash Gourd Cucumber Spinach Sunflower