Expert Advice

Powdery Mildew (Erysiphe Graminis)


Powdery Mildew progresses from barely visible light spots on the individual blades of grass to entire patches of grass that have a white residue, which makes it look like flour has been sprinkled on the lawn. It is important to address the issues causing powdery mildew, if allowed to progress further the grass will eventually turn yellow and die off or become vulnerable to other fatal lawn diseases. This lawn disease thrives in heavily shaded areas with poor air circulation.


To correct the lawn conditions that cause powdery mildew it is important to reduce periods of leaf wetness by watering deeply but infrequently. One inch of water once a week between 4am to 7am will allow the grass leaves to fully dry during the day. Watering deeply once a week is crucial to maintain active growth and will also allow the roots of your grass to deepen and your lawn will be able to repair itself quickly from the disease. To reduce shade and improve air circulation we recommend pruning or removing trees and shrubs that shade the area. You will also want to keep your lawn around 3” long to make sure your grass doesn’t start using its food reserves, which will impact how quickly it recovers.