Fungus Attacks Impatiens 

Downy Mildew is a fairly new fungal disease attacking Florida's top landscape flower, Impatiens (Walleriana). Younger plants or new growth will show the first symptoms of leaves looking yellowish or spotted, as if they've experienced extreme cold or a nutritional deficiency. As the disease progresses there will be a whitish growth (spores) on the undersides of the leaves. Then leaves and flowers will drop, leaving mostly stems. 

The scarest part is that this entire process can happen within a few days time!  The below pictured plants went  from looking thirsty, to dropping all blooms within days. 

Before Downy Mildew         

There is really no known cure. Once the white spores are seen with the above symptoms, it is best to just remove the plants.  Experts warn that chemical treatments are expensive and do not really cure. So your best strategy is to quickly remove and dispose of plants that are affected to save any other susceptible plants near by.

Sadly, most local nuseries have decided they will not be carying the Impatiens next year, although the hybrids, New Guinea and sunPatiens do not seem to be susceptible to the disease.  The main seed producers and growers are researching ways to prevent it in the future.