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powdery mildewMy peas have Powdery Mildew

With the rainy, humid, and cool weather we’ve been experiencing this May in Charlotte aqnd Asheville, fungus diseases both in turf and ornamentals are out in full force. Powdery Mildew is one disease that is host-specific to trees, shrubs, and some flowers and vegetables in the garden. Common susceptible plants are, euonymous, sprirea, crepe myrtle, oak, rose, azalea, crabapple and certain flowers and vegetables. I have a good case of Powdery Mildew in my little pea patch at home, but since we’ve just harvested them, it’s not an issue now. And yes, they were very yummy!

Powdery Mildew shows signs of a white, powdery substance forming over the surface of leaves. The powdery fungal growth can usually be found on the upper surface of the leaves, and often tends to begin on lower leaves. As the disease progresses, leaves can become dwarfed, curled and somewhat distorted. In severe cases, leaves can turn yellow and even dried and brown. As powdery mildew fungi grow over the surface of the plant, they develop structures that are inserted into plant cells and extract nutrients necessary for growth and spore production. This results in a general decline in plant growth and vigor of the plant, as well as the common visible symptoms.

Powdery Milder thrives in moderate temperatures and high humidities, which is exactly what we have now. As it becomes hotter and things dry out some, the disease pressure tends to go away. In the meantime, consider pruning to allow better air circulation and allow more sun exposure to dry things out. If you don’t want to use fungicides, application of a horticulture oil may help. Control can be provided with timely applications of fungicides such as propiconazole (Banner), myclobutanil (Eagle), and thiophante-methyl (Danonil). Eagle would probably be your best bet for good control. Spraying at the first onset of symptoms is best, and as always, follow label instructions.

If Powdery Milder occurs in fescue turf, it’s really not a concern. Just remove clippings if so, and as the weather becomes hotter and drier, the problem tends to go away.


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