What is Impatiens Downy Mildew?
Since 2011, Impatiens downy mildew has decimated Impatiens beds across the globe. IDM is caused by a host-specific water mold, Plasmopara destructor. When present, and environmental conditions are met (high humidity and cool night temperatures), the disease can spread rapidly, resulting in flower drop and eventually plant collapse. Both airborne and overwintering spores can affect susceptible I. walleriana varieties.