Spray plants with malathion, horticultural oil, azadirachtin Neem , or acephate Orthene to control insects that secrete honeydew. The undigested portion is excreted as a sweet, sticky liquid called honeydew. If copious amounts of honeydew form on trees, sidewalks and other surfaces below may become coated with it and the sooty mold that follows.
Ants add to the problem by collecting and tending honeydew-excreting insects, such as aphids, scale, and mealybugs. They milk the insects for the honeydew, which they take back to other ants for food. Ants also transfer honeydew-excreting insects from plant to plant. The bizarrely cool, rainy summer we've experienced in the Southeast this year sorry, everybody out west means that if your crepe myrtle is susceptible to mildew, it probably has it.
Powdery mildew is a filmy, white fungus that grows on leaves and flower buds. It causes leaves to curl and shrivel. Flower buds drop without opening. Back in the day when we didn't have resistant selections, powdery mildew was the 1 complaint people had about crepe myrtles.
White powdery spots appear on leaves, stems, and flowers. The spots expand to completely cover leaves in only a few weeks. If the fungus spreads to flower buds, the buds may not open. There are many different powdery mildew fungi.
The fungus spores overwinter on fruit trees. In spring, the fungus begins to grow, and spores are released to travel on the wind to young leaves. Powdery mildew thrives where cool nights follow warm days. Insufficient sunlight and poor air circulation favor its development. Symptoms: A white or gray powdery fungus appears on foliage and flowers.
Round, white spots on upper leaf surfaces expand and merge, covering both sides of leaves. Infected leaves turn yellowish green to brown. New growth may be stunted, curled, and distorted. Infected blossoms may not set fruit; fruit may develop a rough skin or be covered with the powdery fungus. Fruit drops early or is dwarfed. Solutions: Plant a mildew-resistant crepe myrtle. If yours isn't resistant, spray the foliage according to label directions in early summer with neem oi l, horticultural oil , Natria Disease Control , Daconil, or Immunox.
The first three are natural products. You'll probably have to spray more than once. Powdery mildew usually strikes during periods of warm, humid weather. Apply horticultural oil, triadimefon Bayleton , or triforine Funginex at the first sign of the disease. Prevention: Plant resistant selections; see the "Southern Living Garden Book" under the "Practical Gardening Dictionary" or individual plant listings for suggestions.
Give plants sufficient light and air circulation. Water plants from underneath rather than above to keep leaves dry. Control: Reduce nitrogen fertilizer. Spray fruits and vegetables with wettable sulfur or horticultural oil.
Discard infected flowers of annuals and leftover produce in fall. Cercospora is a leaf spot fungus that used to be fairly uncommon, but isn't anymore.
Grumpy has a theory that the nearly universal planting of crepe myrtles in the South has made it easy for this fungus to spread.
What happens is that in mid- to late summer, angular, brown spots form on the oldest leaves. These leaves then develop fall color prematurely and drop.
Even without a natural resistance, powdery mildew can be managed or prevented by allowing crape myrtles to receive full sun, by proper pruning for light and air flow, and by following best practices for watering and fertilizing.
Growth that is affected by the powdery mildew fungus should be removed in the fall. Generally, systemic fungicides are not recommended for powdery mildew. However, a certified arborist can properly diagnose the extent of a powdery mildew infection, and provide appropriate treatment recommendations. Crape myrtles are a beautiful and important part of our North Texas urban forest. We hope this information will help our community better understand and care for their crape myrtles.
At Texas Tree Surgeons, we love trees and shrubs! As always, let us know if you have any questions about your crape myrtles, or any other trees. A Guide to Crape Myrtles. Basic Care for crape myrtles. Common crape myrtle Issues. Crape Myrtle Topping. Physical damage. Crape Myrtle Aphids. CraPe Myrtle Bark Scale. Sooty mold can ruin the natural beauty of crape myrtles and develop into a health risk.
In the winter after mowing the lawn is over, I run electricity to the tree and provide timed uplight for the trunks. There are three more in the back yard, but the front tree is the highlight of the winter garden. It just takes care. The tree still has a chance to become beautiful once again. It is such a shame what people do to them though they are such beautiful trees when not cut back like that, all cutting them back does is leave you with an eyesore in the winter time and incredibly floppy branches in the summertime.
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Facebook Twitter Instagram YouTube. Have a great spring!! Linda Gay. Angela Bailey on March 17, at pm. Annie on March 22, at pm. Chris on April 23, at am. Steve grgas on June 17, at am. Michael Frost on June 18, at pm.
Janrasco on June 21, at pm. These pests overwinter in the egg stage. And no, a cold winter will not diminish their numbers! They hatch in the spring, then give birth to live young all summer long. These live young are genetically identical to the adult, which is why they are somewhat difficult to kill. When you use a pesticide, it will kill all the aphids sensitive to that pesticide.
The ones left to produce more young are not sensitive to that pesticide, nor will their young be sensitive. A big word that means without sex!
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