Introduction Powdery mildew is a late season disease of many crops.
Some species attack a limited range of plant hosts, other have a broad host range.
Powdery mildew has been present in ginseng gardens for many years. It appears to come from surrounding weed hosts and affects ginseng just before senescence. As a result it goes largely unnoticed by growers. Afffected berries will shrivel and the seed may not develop fully. The disease spreads rapidly through a garden.