Aphids on Crepe Myrtle: How To Identify & Treat the Problem

Gardeners favor crepe myrtles for their stunning blooms and enduring charm all year round.

However, like any plant, they can fall victim to pests, one of the most common being aphids. These tiny insects can cause significant damage if left unchecked.

There are several effective approaches for combating aphids on crepe myrtle trees. You can blast them off with water, use an insecticide, introduce natural enemies, control the ant population, or spray them with soapy water. Repeated applications may be needed.

If you’re noticing signs of aphids on your crepe myrtle, don’t worry. This comprehensive guide will help you identify, understand, and effectively treat the problem.

Key Takeaways

  • Aphids are small, sap-sucking insects that can cause leaf curling, yellowing, defoliation, and stunted growth. They also produce honeydew, which can lead to sooty mold and attract other pests.
  • Preventing aphids involves regular monitoring, promoting natural predators, and maintaining the overall health of your tree.
  • Treatment options for aphid infestations include spraying with water, insecticides, homemade aphid sprays, and controlling ants.
  • Aphids do not bite humans, and while some species can live in soil, most are found on the leaves and stems of plants.

Want to learn about the various diseases and pests that affect crepe myrtle trees? Find all the information you need in my detailed article, Crepe Myrtle Diseases and Pests.

Understanding Aphids

Aphids, also known as plant lice, are small, soft-bodied insects that feed on plant sap. There are many different species of aphids, but they all share certain characteristics and behaviors that can help you identify them.

How To Identify Aphids

Aphids are typically less than 1/8 inch long and can be green, yellow, brown, red, white, or black, depending on the species.

They have pear-shaped bodies with long antennae and two tube-like structures, called cornicles, protruding from their rear end. Aphids are usually found in clusters on the underside of new leaves or stems.

What Causes Aphids?

Aphids are attracted to plants with new growth because they prefer to feed on young, tender plant tissue.

They are often brought into gardens by ants, which farm them for their honeydew, a sweet substance that aphids excrete as they feed.

Aphid Life Cycle

The aphid life cycle is complex and varies between species. However, most aphids reproduce asexually with females giving birth to live young without mating.

In warm weather, a female aphid can produce up to 80 offspring in a week. Some species also produce winged forms that can fly to new plants when the population becomes too large or the plant becomes overcrowded.

Signs and Symptoms of Aphid Infestation

Signs of an aphid infestation include curled or yellowed leaves, stunted growth, and a sticky substance on the leaves or ground beneath the plant (this is the honeydew).

You may also see a black, sooty mold growing on the honeydew or ants traveling up and down the plant.

Ants farming aphids on a plant stem.

Impact of Aphids on Crepe Myrtle Trees

Aphids can have a significant impact on crepe myrtle trees. While a small number of aphids may not cause noticeable damage, a large infestation can lead to a range of problems.

Damage to Tree

Aphids feed by piercing plant tissues and sucking out the sap. This can cause leaves to curl, yellow, or drop prematurely. In severe cases, aphids can cause significant defoliation and dieback.

Effects on Tree Health and Growth

By draining the sap, aphids can weaken the tree and stunt its growth. Additionally, as they feed, aphids inject saliva into the plant, which can cause further damage or even transmit plant diseases.

Honeydew Production

Aphids excrete a sugary substance called honeydew as they feed. This sticky residue can coat leaves, branches, and the ground beneath the tree, attracting ants and promoting the growth of sooty mold.

Secondary Issues

The honeydew produced by aphids can lead to the growth of a black sooty mold. While this mold doesn’t directly harm the tree, it can block sunlight, affecting photosynthesis.

Additionally, the presence of aphids can attract other pests, like ants and wasps.

How To Prevent Aphids

Preventing aphids involves regular monitoring, promoting the presence of natural predators, and maintaining the overall health of your tree. Healthy trees are less likely to suffer severe damage from aphids.

Crepe Myrtle Aphids Treatment

If you’ve detected an aphid infestation on your crepe myrtle, there are several methods you can use to control it.

1. Spray Off With Water

A strong spray of water from a garden hose can dislodge aphids from your tree. This is a simple and eco-friendly method, but it may need to be repeated regularly for heavy infestations.

2. Insecticide for Aphids

Insecticides can be effective against aphids. Choose a product labeled for use against aphids, and follow the manufacturer’s instructions. I recommend this one.

Remember that it’s important to spray the underside of leaves where aphids often congregate.

3. Natural Enemies of Aphids

Beneficial insects, like ladybugs, lacewings, and certain types of wasps, are natural predators of aphids. Encouraging these beneficial insects in your garden can help control aphid populations.

4. Homemade Aphid Spray

A homemade spray made from dish soap and water can also be effective against aphids. The soap dissolves the aphids’ protective waxy coating, causing them to dehydrate and die.

5. Get Rid of Ants on Tree

Ants farm aphids for their honeydew and will protect them from predators. Therefore, controlling ants can help reduce aphid populations.

Related Questions: 

Do Aphids Bite Humans?

No, aphids do not bite humans. They feed on plant sap, not blood. They will not hurt you in any way, but they can damage the plants on which they feed.

Do Aphids Live in Soil?

Some species of aphids can live in the soil during part of their life cycle, but most are found on the leaves and stems of plants.

Closing Thoughts 

Aphids can pose a significant threat to crepe myrtle trees, causing damage and potentially leading to secondary issues.

However, with regular monitoring, preventative measures, and effective treatment strategies, you can protect your crepe myrtle from these pesky pests.

Remember that a healthy tree is the best defense against any pest or disease.

Pests and diseases love Crepe Myrtle trees. Here are some other things to look out for: