Powdery Mildew

Erysiphe graminis

Disease description
A gray or white coating of mycelium and spores develops on leaves, especially on some cultivars of Kentucky blue grass. Leaves may turn yellow, orange or brown. All regions. Rarely severe on mature turf in Prairies until fall.

Predisposing factors

shaded situations under trees or north sides of buildings, from May to November
first-year seedlings of some Kentucky blue grass cultivars in open situations may be severely damaged
excessive or deficient nitrogen favors disease
cultivars of Kentucky blue grass vary greatly in resistance in different regions, depending on physiologic form of pathogen present.

Cultural control
Use creeping red fescue for lawn turf in shaded situations rather than Kentucky blue grass. Cultivars of the latter vary in resistance according to prevalence of physiological races but Dormie, Sydsport, and Nugget often show little disease. Flyking, and Merion are moderately resistant and Park susceptible. Raise height of cut, avoid excessive nitrogen.

For information about other diseases that affect turf grasses, go to Major Diseases of Turf Grasses in Western Canada.

For more information about the content of this document, contact Ron Howard.
This document is maintained by Shelley Barkley.
This information published to the web on November 20, 2001.
Last Reviewed/Revised on November 7, 2007.