Control of Aphids and Sooty Mold on Crape Myrtles

Search for aphids on new crape myrtle growth. Aphids are easy to identify because they typically form large colonies. Aphids thrive on newly bloomed plants because they contain high nitrogen levels. When they start infesting the plant, you will see the leaves underneath turn a yellowish color. If not treated, over time the leaves become black with sooty mold.

Kill individual aphids, if you see them, by squashing them with your gloved fingers. Be sure to wear gardening gloves. These will protect your hands from fungi and other contaminants.

Spray water directly on contaminated sections of the crape myrtle. For best results, use a nozzle attachment with your garden hose or a high-pressure sprayer. Do this repeatedly until the insects lose their grip on the plant.

Make a soap-based insecticide to control the more resistant aphids. Combine 1 tablespoon of horticulture oil, 1 tablespoon of insecticidal soap and a pint of water. Pour the mixture into a plant spray bottle and apply to the infected areas. Some alternatives to insecticidal soap include botanical insecticides such as pyrethrums or neems. Certain household products such as laundry soap and chlorine bleach will also kill aphids. Use these sparingly and with extreme caution.

Monitor the crape myrtle plants closely, especially during the summer months when aphids will appear in large numbers as the temperature rises.