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Tree and Shrub Diseases: Powdery Mildew

powdery mildew treesPowdery Mildew is a relatively easy disease to spot when it infects trees and shrubs in the landscape. Although the disease will not kill the plant outright, it will compromise the vigor of the tree or shrub and leave it more susceptible to other diseases, insects or stresses.

The first signs of powdery mildew are light green or yellow spots on the leaf of the plant. As the disease matures, a white film covers portions or the entire leaf (the appearance of flour sprinkled over the leaf). The disease tends to target plants in spring and fall when weather is cool and humid, though it may show up anytime during the growing season if ideal conditions are met.

 

 

Disease Development Favored by:

  • Cool, humid weather
  • Shaded areas
  • Areas with little air circulation

Corrective Measures:

  • Prune susceptible plants to promote air flow
  • Water in the morning or early evening
  • Remove infected leaves and discard
  • Dormant Oil may help prevent powdery mildew from occurring

Image By: Haruta Ovidiu, University of Oradea, Bugwood.org

If you believe your trees or shrubs have been affected with disease or fungus activity, call Grounds Services today for a no-obligations visit at 419-536-4344.