Treat Mildew on Plants with Two Great Anti Fungal Rx Treat Mildew on Plants | We’ll show you two really great homemade spray recipes for treating powdery white mildew on plants. Mildew is a common plant disease that can affect various types of plants in the garden. If left untreated, it can inhibit plant growth and even cause death in severe cases. Fortunately, there are several methods you can use to effectively treat mildew on plants. PBS-TV’s Loren Nancarrow shows…