Downy mildew is the is one of the destructive foliar diseases of mainly many vegetables, mainly cucurbits and even other horticulture crops. Initially chlorotic pale green to yellow or brown spots appear on upper leaf surface, mainly on older crown leaves. Infection is more during damp humid conditions, where fungus sporulates on the lower surface of leaves as violet/gray/white downy fungal growth. It leads to stunted growth of plants, severely infected leaves wilt, wither, die and shed from plants. It affects stem, flowers and fruits, causing reduced fruit set and reduced yield and quality of fruits. It occurs at nursery, leading to wilting and collapse of seedlings. If not controlled effectively leads to major yield loss.