Downey Mildew problem for Impatiens
Starting in late 2011 the downey mildew disease of impatiens called Plasmopara obducens made its first appearance in Florida. This disease has been known in other parts of the US for many years. In Europe this disease has caused rapid destruction of impatiens. There have been reports of the disease in Costa Rica, Guatemala, and Central America. The potential for this disease to become widespread is enormous.
This disease likes cool moist conditions, so with summer here we may get a break until the cool weather returns. Water and wind easily disperse the sporangia (a single celled or many celled structure in which spores are produced, as in fungi, algae, mosses, and ferns. Also called spore case.) produced on infected plants with younger tissue being more susceptible.