Downy mildew is a pathogen of both vegetative and seed-produced Impatiens walleriana (the garden impatiens) throughout the world and has been reported in the United States, Canada, Asia, Europe and India. In the United States, Downy Mildew on Impatiens walleriana was first reported in 1942. Since that time, Downy Mildew on Impatiens walleriana has occurred sporadically throughout the United States.