The past season was very favorable for the development of the Powdery Mildews. During the month of September Mr. G. W. Carver, a special student in the botanical laboratory, brought in a fine lot of The Apple Powdery Mildew. An Erysiphe and the common Powdery Mildew of the cherry, Podosphaora oxyacanthae, have been reported on Pyrus malus. But our fungus does not belong to either of these genera. It agrees with the descriptions given for Spherotheca mali (Duby) Burrill. It is easily recognized by its persistent perithecia, two kinds of appendages. The long appendages come from the upper end; they are straight or curved, rigid, usually septate, and occasionally forked at the end. The base is deeply colored. The rudimentary appendages are floccose and attached to the smaller end of the pyriform perithecium. Prof. Burrill records this species abundant at times in the Mississippi Valley, and first referred it correctly to Duby's Erysiphe mali. Bot Gall, p. 869.
Proceedings of the Iowa Academy of Sciences
©1893 Iowa Academy of Science, Inc.
Pammel, L. H.
"Powdery Mildew of the Apple,"
Proceedings of the Iowa Academy of Science, 1(Pt. 4), 92-92.
Available at: https://scholarworks.uni.edu/pias/vol1/iss4/27