What Is This Black Mold On My Crepe Myrtle?

The black mold on a crepe myrtle is attributed to aphids.  Here in Macon / Warner Robins crepe myrtle aphids reproduce quickly. This makes it easy for them to rapidly grow into a large population that will damage your crepe myrtle.  Found throughout April through September, these tiny insects do damage by feeding on the soft tissues and plant sap of crepe myrtle leaves.

This type of aphid is species-specific meaning it only feeds on crepe myrtles. As a homeowner you only need to worry about this type of aphid if you own a Crepe Myrtle; however, there are other types of aphids that prey on other tree species and show similar signs of damage.

black mold on crepe myrtle

How do I know if I have aphids on my crepe myrtles?

  • Honeydew
  • Sooty Mold
  • Ants on the Tree chasing the “honeydew”
  • Drooping Leaves
  • Yellow Spots
  • Black small dots on the underside of the leaves


Honeydew is the excrement of plant-sucking insects such as aphids. Many homeowners confuse honeydew with sap.   Trees do not drip sap. If you have “sap” dripping from your tree it is honeydew and is a telltale sign of an insect infestation.

Sooty Mold:

The black mold on a crepe myrtle is a fungus that grows on top of honeydew and coats the leaves of your trees to the point where they can no longer absorb sunlight. This interrupts photosynthesis and the tree will not be able to produce the nutrients they need for survival. If your trees and shrubs are turning black you most likely have a sooty mold problem caused by an insect infestation.

We see clients with serious problems with Honeydew and Sooty Mold staining their sidewalks, fences, and house siding black. If you are having staining issues from Honeydew and Sooty Mold our arborist will be able to determine if it’s being caused by aphids, scale, or other plants sucking insects and recommend the appropriate treatment.

black mold on crepe myrtle

How do I get rid of aphids?

Organic Control through Beneficial Insects

Aphids have many natural enemies, including lacewing larvae and ladybugs. Some companies can release these predators on your property in order to control the population of these aphids, but this is not a realistic option to control aphids.

Foliar Spray

foliar sprays will kill aphids on contact. When not correctly applied these sprays can hurt beneficial insects; however; our lawn care specialists abide by Integrated Pest Management Protocol. This protocol utilizes techniques that help target the intended pest while leaving the majority of the beneficial insect population unharmed.

Systemic Root Injection

we inject systemic insecticides into the root system that will be translocated throughout the plant.  When the aphids attack the foliage they ingest the insecticide that has moved from the root system to the foliage.

If you have aphids on crepe myrtles sign up for our plant health care program with a lawn care specialist or by calling 478-318-7644. Find out more about damaged insects here or read about good lawn bugs.