Erysiphe platani

Erysiphe platani, also known as sycamore powdery mildew, is a fungus native to North America that now infects sycamore tree species worldwide.^[2] Infections may spread rapidly in urban settings with large groups of young trees or in plant nurseries.^[3] This mildew thrives when there are high humidity conditions during the growing season.^[4]

Erysiphe platani
Sycamore powdery mildew, Western Cape, South Africa
Scientific classification
Kingdom:	Fungi
Division:	Ascomycota
Class:	Leotiomycetes
Order:	Helotiales
Family:	Erysiphaceae
Genus:	Erysiphe
Species:	E. platani
Binomial name
Erysiphe platani (Howe) U.Braun & S.Takam. (2000)
Synonyms[1]
Microsphaera platani Howe (1874)

Symptomatic trees show leaf discoloration and puckering as the mildew spreads across buds and leaf surfaces.^[5] The most visible effects, which include "leaf curling, stunting, and distortion,"^[6] appear on vulnerable newly emerged leaves.^[4] This infection only appears on leaves, it has no obvious effect on stems and branches.^[5] Fertilization and pollarding increase the number of young shoots, which are the parts of the trees most vulnerable to infection.^[6]