Question
What is the best methods for controlling Apple powdery mildew?

Answer
Control

Apple varieties vary greatly in their susceptibility to powdery mildew. Jonathan, Granny Smith, Mutsu (Crispin), Rome, Cortland, Baldwin, Monroe and Idared are very susceptible and should be avoided if powdery mildew is a problem. Most other varieties may also be infected if inoculum is present and conditions are favorable for infection.

Plant trees in sunny locations with good air drainage. This reduces the humidity around trees and reduces the chances of disease.

Where powdery mildew is a problem, a good fungicide spray program is generally required for control.



Sprays are not necessary in many backyard situations. However, if you have had serious powdery mildew damage in past years, treat at 2-week intervals, beginning when buds just start to open (green tip stage), until small, green fruit are present.  Sulfur, horticultural oils, neem oil, potassium bicarbonate, AQ10, and Serenade are all registered for powdery mildew in these crops. Best control of powdery mildew is obtained when the first fungicide spray is applied when the flower buds are just beginning to turn pink. Sprays should be continued every 10- to 14-days until terminal growth has stopped.

Check with your local nursery/garden type store for a fungicide for apple powdery mildew.