Podosphaera minor

Podosphaera minor is a species of powdery mildew in the family Erysiphaceae. It is found in the Americas and Eurasia, where it affects plants in the genus Spiraea.^[1][2]

Podosphaera minor
Podosphaera minor on Spiraea in Canada.
Scientific classification
Kingdom:	Fungi
Division:	Ascomycota
Class:	Leotiomycetes
Order:	Helotiales
Family:	Erysiphaceae
Genus:	Podosphaera
Species:	P. minor
Binomial name
Podosphaera minor Howe, 1874
Synonyms
Microsphaera fulvofulcra Cooke, 1877 Podosphaera oxycanthae f. spiraeae Jacz., 1927

Description

The fungus forms greyish, thin mycelium on host leaves. Podosphaera minor, like most Erysiphaceae, is highly host-specific and infects only Spiraea.^[1] Other species also infect the same genus, including Podosphaera spiraeae which is common on cultivated Spiraea in the same regions as P. minor, but rather causes dense, whitish, shoot-distorting growth. Podosphaera spiraeae-douglasii can be found on Spiraea douglasii. Podosphaera spiraeicola is found in East Asia.

Taxonomy

The fungus was formally described in 1874 by Howe. The species comprises two varieties: var. minor and var. longissima. The former has shorter chasmothecial appendages than the latter, which is found in North America.^[1]