Powdery mildew is a very common plant disease among the berry family. Damage from powdery mildew shows up on berry plants in the form of a whitish or greyish powder. This ashy like powder can be found on almost all parts of the plant, and especially on the leaves, fruit and younger cane tips. In addition, powdery mildew may cause the canes to grow in a distorted manner so that canes are dwarfed or crooked. Powdery mildew can also cause the berries themselves to wither and die off.
Powdery mildew is composed of fungal patches and spores.
When the wind blows, the spores are transplanted and spread to healthy plants. Splashing water or rain can also spread the spores and fungal strands. Once the fungi infect the berry plants, they begin to sap the energy and nutrients of the plants until they begin to die off. This may first appear in yellowing of the leaves and eventual leave death. Powdery mildew attacks many plant varieties and therefore can be spread to berry plants from unrelated species, just as berry plants which are infected with the fungi can spread spores to other plants in your garden.