Powdery Mildew Is Back in Burke

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The all too familiar powdery mildew calls are starting to come in. People always start off by stating that their plants have a white to gray powder all over the leaves. Sometimes it is also on the flowers and stem of the plant but not always. Eventually the leaves turn yellow and fall off or curl up. It is a common problem in Burke County as it it is in most places that have high humidity. Oddly enough it doesn’t require moisture but high humidity is a must.

Powdery mildew is a fungal disease that affects many fruits, vegetables and ornamentals. There are many different strains of the fungus and most are very specific to the variety of plant they will attack. For example, the powdery mildew that attacks rose bushes is probably not the same powdery mildew that attacks tomatoes.

It usually doesn’t grow on vegetable fruits but if the plant is severely infected it can result in reduced yields and shorter harvest times. Fruits can also lack flavor. Powdery mildew spores can over winter in weeds and crop debris. In the spring when temperatures are between 60 and 80 degrees, spores are spread by wind to susceptible plants.

Ornamentals are also affected by powdery mildew with roses and crape myrtles being some of the most likely plants to show up with the disease.

Whether your problems are with vegetables or ornamentals the best control is prevention. Resistant varieties of both ornamentals and edibles are available and should be used when the disease is a constant problem. Early applications of fungicides is also a key factor when powdery mildew is an on going issue. Apply fungicides early in the season before powdery mildew shows up and continue to spray throughout the growing season. Horticultural oils, neem oil and sulfur sprays are good non-toxic preventives while alternating applications of commercial fungicides such as Daconil and Immunox also do a good job. Always, ALWAYS read the label before applying any chemical to make sure that it is appropriate for the plant.

Planting in sunny areas with good air movement and sufficient space in between plants will also help to prevent powdery mildew. The best action against most pests is usually a combination of more than one technique. It is up to the gardener to educate himself about the possible pests that can affect the plants in his garden.

CucmberPowderyMildew

Powdery Mildew on Cucumbers

RosesPowderyMildew

Powdery Mildew on Roses

Written By

Photo of Donna TeasleyDonna TeasleyExtension Agent, Agriculture - Horticulture (828) 439-4460 Donna_Teasley@ncsu.eduBurke County, North Carolina
Posted on May 19, 2016
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