As the aphid feeds, it injects saliva into the leaf. The saliva causes yellow spots to develop on the leaf. Their feeding on young leaves often causes distortion of leaves. Buds, branch tips and flowers can also be affected by feeding. Consider using these in new plantings.
Several predators feed on the crape myrtle aphid.
As much as possible, these natural predators should be allowed to reduce aphid populations. In addition, aphids can sometimes be removed from plants by spraying with a strong stream of water. Spraying with water may have to be repeated regularly, as needed. As a result of their phenomenal reproductive rate, aphids are very difficult to control with insecticides. If a single aphid survives, a new colony can be produced in a short period of time.