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Powdery Mildew

powdery mildew

What is Powdery Mildew?

Powdery mildew is a common disease that affects many species of trees and other types of plants. (See Susceptible Plants below). You can identify powdery mildew on your plants by the white, spore growth that forms on leaves, flowers and fruits. “This disease can be serious on woody species such as roses, crape myrtles, and sycamore trees where it attacks new growth including buds, shoots, flowers and leaves.” (Gubler)

How does Powdery Mildew spread?

Powdery mildew is spread by wind to new hosts. In some plants such as roses, powdery mildew can survive season to season. The most susceptible places for plants to develop this disease are shaded areas and temperatures of 60 to 80 degrees.

Treatment Options:

  • Fungicide Treatment

    Tree DoctoRx offers a fungicide treatment to control the powdery mildew disease. The best time to treat your trees and shrubs are during the spring season. Multiple applications may be needed for control on this disease. Contact us for more information.

For more information on Sycamore Scale, go to the following link:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7493.html


Susceptible Plants to Powdery Mildew
Aster Crape Myrtle Oak
Azalea (deciduous) Dahlia Pansy
Begonia (tuberous) Delphinium Phlox
Calendula Euonymus Ranunculus
California poppy Forget-me-not Rose
China aster (Callistephus) Gaillardia Rhododendron
Chrysanthemum Hydrangea Rudbeckia
Clarkia Lilac Snapdragons
Columbine London plane tree Sweet pea
Coral bells (Heuchera) Lupine Verbena
Corn flower Mint Vinca
Cosmos Monarda Zinnia

 

Reference: Gubler, W. D. 'Powdery Mildew On Ornamentals'. UC IPM. N.p., 2009. Web. 15 July 2015.

UC Statewide IPM Program, University of California, Davis, CA 95616,. Table 2. Common Ornamentals Susceptible To Powdery Mildew. 2009. Web. 15 July 2015.

UC Statewide IPM Project,. Powdery Mildew, Microsphaera Alni, On Sycamore Leaves.. 2000. Web. 15 July 2015.