The cleistothecia are dark brown,
globose, with many unbranched appendages. There are multiple asci within
each cleistothecium. This genera causes powdery mildew disease on plants
such as clover, cucurbits, beans, soybeans, delphinium, hydrangea, zinnia,
phlox, aster, crepe myrtle, and tulip poplar.
Representative Species
Erysiphe polygoni
causes powdery mildew disease of beans, soybeans, clovers, and other legumes, cabbage, beets, cucumber, cantaloupe, delphinium, and hydrangea.Erysiphe cichoracearum
causes powdery mildew disease on squash, aster, phlox, zinnia, verbena, and hellianthus