Does Mildew Attract Flies?

Symptoms

• Plants affected by mildew fungi start to display a light white or gray, powdery growth on the foliage, stems, flowers or fruit. With disease progression, this growth gets dense and covers more areas. New foliage and shoots are stunted in growth. Leaves are twisted and curled. Mildew does not invite flies or other damaging pests. The disease is not fatal to plants, but affected leaves start to fall and flowering is affected.

Susceptible Plants

• The disease-causing fungi affect nearly all ornamental plants including shrubs, trees and herbaceous plants. Evergreen and deciduous, woody plants such as cherry, dogwood, azaleas, honeysuckle, roses, wintercreeper and viburnum frequently display symptoms of the disorder. The fungus causing the disease is usually host specific. The mildew fungus on roses will not affect lilac or viburnum growing next to it.

Favorable Conditions

• Mildew-causing fungi thrive under warm and humid conditions with optimal weather temperatures of 60 to 80 degrees Fahrenheit. Very hot weather retards fungal growth. Plants growing in poorly ventilated and shaded landscape areas or that are crowded are more prone to infection.

Management

• Inspect new plants carefully and make sure there are no disease symptoms. Do not crowd plants in the landscape and choose a sunny, airy location rather than damp shade. Minimize the use of overhead sprinklers as wet foliage promotes fungal growth. Fungicidal control options include use of products containing triadimefon, thiophanate-methyl or triforine.