**5.2 Genera:** *Erysiphe, Sphaerotheca*

Two genera (Erysiphe, Sphaerotheca) have been identified to cause powdery mildews which affect economically important crops, herbs and woody species [77, 78]. Members of the genera are obligate plant pathogenic fungi. *Erysiphe* is the largest in the family Erysiphaceae, comprising about 873 species. About 806 plant species are found in the genus *Sphaerotheca*.
