An aphid infestation can be quite distressing when you find leaf spots, discoloration, and black sooty mold on your lush green leaves. Before you panic, rest assured that aphids are very common pests for Crape Myrtles, and they can be controlled with a little extra attention.
If you spot aphids or aphid damage on your Crape Myrtle, give nature a chance to run its course first. Ladybugs and other natural predator insects can typically control aphid populations. For severe infestations, there are natural and chemical treatments you can use to finish the job.
This article will tell you everything you need to know about Crape Myrtle aphids and what you can do about them. We’ll share the most common chemical treatments you can use and share some of our favorite natural remedies for aphid problems. We’ll also let you know what you shouldn’t do about aphids.
Will Aphids Kill a Crape Myrtle?
Aphids alone will not typically kill a mature Crape Myrtle. Small numbers of these tiny insects will only do minor damage, but major infestations can cause bigger problems. Still, aphids usually only cause cosmetic damage to Crape Myrtles, as their feeding results in holes in leaves and a sticky residue that can lead to other problems.
The good news is that aphids haven’t been shown to cause significant or long-term damage to Crape Myrtles or impact their overall health or vigor in most cases. However, aphids can reproduce quickly, and a small number can quickly become a larger infestation if they’re not controlled. Heavy infestations can cause leaf yellowing, leaf drop, and black sooty mold on the leaves.
When aphids feed, they also secrete a sugary substance known as honeydew, ejecting it away from their bodies, so they don’t get stuck in it themselves. The result is heavy accumulation on leaves and stems below the aphids’ feeding sites. So, when you notice a shiny layer of sticky “sap” on your Crape Myrtle leaves, check the foliage above for signs of aphids.
The honeydew is harmless, but various molds and other microorganisms may develop in those areas, using the sugary secretion as a food source. Ants also enjoy eating the honeydew, so if you notice a trail of ants going up the side of your tree, it’s another signal that you may have aphids or another honeydew-producing pest.
What Are Crape Myrtle Aphids?
Crape Myrtle aphids (Tinocallis kahawaluokalani) are the most common pests affecting Crape Myrtles. These tiny insects only feed on Crapes, so you don’t have to worry about them jumping onto other plants in your landscape. These aphids are tiny, making them difficult to spot with the naked eye. They’re only about 1/16 to ⅛ inch long, and they’re usually a light green to yellow color, making them even harder to spot on leaves. A very up-close look would reveal black spots on their abdomens.
Adult aphids lay eggs in the fall or winter, which hatch in the spring when the weather starts to warm. Then, they give birth to live young during the spring and summer months. So, at any given time, there may be many, many generations of aphids feeding on your plant. Still, the mere presence of aphids is no reason to panic.
These minuscule insects don’t damage the plant beyond cosmetic issues, and any problems typically resolve themselves within a single growing season. Aphids eat mainly new leaves by inserting their mouthparts into the leaf and sucking out the phloem (leaf sap). As they feed, the Crape Myrtle aphids inject their saliva into the leaf and excrete a sugary liquid known as honeydew. Aphid saliva can cause yellow spots and leaf discoloration, and very young leaves may curl and fall off.
Why Aphids Are Attracted to Your Crape Myrtle
If you don’t have a widespread aphid problem in your yard or garden, you may wonder why these little bugs are so attached to your Crape Myrtles. There’s a very simple explanation – these insects are monophagous, meaning they feed exclusively on Crape Myrtle and don’t have an appetite for anything else in your landscape.
Since Crape Myrtle aphids only eat Crapes, they will search for the plants and make themselves at home. In fact, adults lay eggs that overwinter with the Crape Myrtle, then they’ll hatch come springtime when the tree starts leafing out again.
However, Crape Myrtle aphids aren’t the only type of aphid to affect Crape Myrtles. Cotton aphids, melon aphids, and black citrus aphids have all been reported to feast on Crape Myrtles. Still, the most common is the one that shares its namesake.
In many cases, aphid infestations are most severe on trees that are already dealing with some other issue. If your Crape Myrtle is drought stressed, has poor air circulation, doesn’t get enough sunlight, or is root bound, it may be more susceptible to an infestation.
How to Control Aphids
There are a few different ways to control aphids on your Crape Myrtles. First, you can go the chemical route and use an appropriate pesticide or other treatment to rid your tree of aphids. However, that might be difficult if you have a huge tree or don’t want to impact other beneficial insects. There are also natural solutions to combat these tiny pests. It’s always a good idea to try a less-extreme measure first, then move on to something stronger if needed.
In any case, the best defense against aphids includes the solutions that nature has already put into place. Aphids have several natural predators that will keep the population under control as long as the conditions are right for them. Ladybird beetles (ladybugs), ladybug larvae, green lacewings, hoverfly maggots, and parasitic wasps are all known natural predators. These insects will naturally reduce aphid populations on your Crape Myrtle.
Best Chemical Sprays and Treatments
If natural predators aren’t doing the job of ridding your Crape Myrtle of aphids, you can turn to various chemical sprays and treatments to supplement their work. In all cases, you should look for products that are selective in what they kill as not to harm beneficial insects. Chemical treatments can be spray applications that you apply to the leaves and foliage, or you can use a soil drench method that works through root absorption.
Here are some of the most common options that aren’t as harmful to other insects like natural aphid predators:
Chemical Treatment | Brand Name | Treatment Type |
Acetamiprid | TriStar | Leaf Spray or Soil Drench |
Dinotefuran | Safari | Leaf Spray |
Imidacloprid | Marathon II, Merit, Bayer Advanced Tree & Shrub | Leaf Spray or Soil Drench |
Pyriproxyfen | DIstance | Leaf Spray or Soil Drench |
Imidacloprid is a popular choice for soil drench applications because it can absorb into the root system and move up through the stems and leaves. Not only is it an obvious choice for big and tall trees, but there’s also the benefit of applying the chemical to the soil versus spraying it into the air and onto foliage to affect other insects.
Then, when the aphids and other bugs munch on the Crape Myrtle leaves, they will ingest the pesticide. However, you should use caution with this chemical and avoid applying it to the soil while your Crape Myrtle is in bloom. Otherwise, it could expose bees and other pollinators to the pesticide through the pollen and nectar.
That means the best time to apply a soil drench containing imidacloprid is right after your Crape Myrtles have finished blooming for the summer or just before they begin leafing out in early spring. That will give the plant time to absorb the chemicals without impacting the blooms too much.
Avoid pesticides containing permethrin, bifenthrin, organophosphate, or carbamate (brands like Orthene or Sevin). These are non-selective pesticides that will kill almost anything they come into contact with.
Best Natural Alternatives
If you want to go with something more natural, there are other options to help control Crape Myrtle aphid infestations that don’t involve dangerous chemicals. Horticultural Oil and Neem Oil are both effective natural alternatives to traditional pesticides. It’s a topical remedy that you simply spray on the leaves and foliage. Apply a full, even coverage to both sides of the leaves and allow the spray to dry. Since these products require direct contact with the pests, you may have to do multiple applications to fully contain the infestation.
Insecticidal soap is another good option for controlling aphids. Like the oils we mentioned, insecticidal soap kills through contact, so you may have to do multiple applications to kill the whole brood. These natural alternatives are good choices for households with kids or pets, or if you want to protect pollinators and other beneficial insects.
When using oils or soaps, follow the instructions on the label carefully! There are usually temperature considerations to prevent leaf damage. It’s best to apply these sprays in the evening when the sun is starting to go down, and temperatures are cooler so that you don’t burn the leaves of your Crape.
If you don’t want to apply any chemical substances to your Crape Myrtle, you can go with manual removal using a stream of water. Spraying leaves with a strong burst of water from your garden hose can be enough to knock the aphids off the leaves. You may have to do this a few times to get the job done.
The best defense is a good offense when it comes to pest infestations. You can prevent aphid problems (and help control any that are present) by introducing more live ladybugs into your garden or encouraging them to stick around. Providing water sources, places for them to have a habitat, and avoiding the use of insecticides can all help your ladybug (and other natural predators) population thrive.
Which Crape Myrtles are Resistant to Aphids?
Several Crape Myrtle cultivars and hybrids are highly resistant to Crape Myrtle aphids. If you have a severe aphid problem and want to avoid the trouble of dealing with an infestation, you can plant one of these varieties to keep the aphids away.
These are Crape Myrtle hybrids (Lagerstroemia indica x fauriei) that have moderate aphid resistance:
- Muskogee
- Natchez
- Tuscarora
- Acoma
- Tuskegee
- Hopi
- Pecos
- Zuni
- Biloxi
- Miami
- Wichita
- Apalache
- Comanche
- Lipan
- Osage
- Sioux
- Yuma
- Caddo
- Tonto
- Choctaw
- Fantasy
Consider one of these when you’re in the market for a new Crape Myrtle to prevent aphid issues in the future.
Putting It All Together
Aphids can be pesky pests, especially when they result in large infestations on your plants. Crape Myrtles are most susceptible to Crape Myrtle aphids, which are a specific type of aphid that only eat Crape Myrtles. The good thing is that you won’t find these hungry critters munching on your other plants once you remove them from your Crape Myrtles.
Still, having an infestation can be very distressing, especially when it causes visible cosmetic damage. Since Crape Myrtle aphids result in honeydew coating on leaves and often cause black sooty mold, it can be a very concerning problem. However, you should remember that these issues are purely cosmetic, and they shouldn’t kill your Crape Myrtle or cause any long-term damage to the plant’s health or vigor.
Remember, the best defense against aphids and other pests is to keep your Crape Myrtle healthy. Ensuring it gets enough sunlight, good air circulation, and the right amount of water are all key to maintaining its health. Proper pruning is also vital to maintaining your Crape Myrtle so that it doesn’t get too congested and air can still flow through. To learn everything you need to know about pruning your Crape Myrtle, check out this article.
When the bugs start bugging you, let natural predators and the “good guys” in your garden do their job to control aphid populations naturally. Then, if they need a little help, you can try a natural alternative like Neem oil or insecticidal soap first. Stronger chemicals and pesticides should be a last resort in most cases.
As always, be sure to read the labels carefully and follow the directions whenever you use any store-bought products for your lawn or garden and use them sparingly. Always investigate whether or not the chemicals you use will harm other beneficial insects and stay away from the ones that do so!