Crape Myrtle Diseases & Insect Pests (2022)

Crape myrtles (Lagerstroemia indica) are essentially trouble-free small trees. The most common problems include powdery mildew, Cercospora leaf spot, aphids, Japanese beetles, and sooty mold. More information on successfully growing crape myrtles is available in HGIC 1008, Crape Myrtle, and HGIC 1009, Crape Myrtle Pruning.

Diseases

Crape Myrtle Diseases & Insect Pests (1)

Powdery mildew typically coats the flower buds (above) and foliage of crape myrtle.
James Blake, ©2007 HGIC, Clemson Extension

Powdery Mildew: Powdery mildew is one of the most common problems of crape myrtle, and it is caused by the fungus Erysiphe lagerstroemiae. Patches of white to grayish powdery growth occur on the surfaces of leaves, flowers, and new shoots. Heavily infected flowers may fail to open. Infected parts of the plant become distorted and stunted. The disease is most serious in shady, damp locations, especially where plants are crowded and air circulation is poor. Development of the fungus is favored by high humidity at night and dry, mild daytime conditions, as often occur during the spring and fall.

Prevention & Treatment: The most effective control measures include locating plants in full sun, removing sprouts from the base of the plant, and planting resistant varieties. Susceptible varieties of crape myrtle should be avoided. Removing diseased twigs and branches may be possible if only a few shoots are infected. Remove sprouts (suckers) at the base of the plant as they occur since they are very susceptible to powdery mildew. Once these sprouts become infected, the fungus easily spreads to the upper portions of the plant.

Plant Resistant Varieties: The extent of resistance to powdery mildew for a particular variety may vary from location to location and may depend on particular conditions occurring in the environment.

  • The Lagerstroemia indica x fauriei hybrids developed at the U. S. National Arboretum in Washington, D. C. are resistant to powdery mildew.
  • Varieties with very good resistance to powdery mildew and fairly good tolerance to Cercospora leaf spot include: ‘Apalachee,’ ‘Basham’s Party Pink,’ ‘Caddo,’ ‘Dodd #2’, ‘Fantasy,’ ‘Glendora White,’ ‘Hopi,’ ‘Lipan,’ ‘Miami,’ ‘Osage,’ ‘Pecos,’ ‘Regal Red,’ ‘Sarah’s Favorite,’ ‘Sioux,’ ‘Tonto,’ ‘Tuscarora,’ ‘Tuskegee,’ ‘Velma’s Royal Delight’, and ‘Wichita.’ ‘Apalachee’ and ‘Fantasy’ are totally resistant to powdery mildew.
  • ‘Catawba,’ ‘Cherokee,’ ‘Seminole’, and ‘Yuma’ have some resistance to powdery mildew.

Varieties to Avoid: ‘Gray’s Red,’ ‘Orbin’s Adkins, ‘ ‘Carolina Beauty,’ ‘Wonderful White,’ ‘Raspberry Sundae’, and ‘Potomac.’

(Video) Identifying Diseases of Crape Myrtles

If the disease is severe enough to warrant chemical control, select a fungicide containing one of the following: myclobutanil, propiconazole, thiophanate-methyl, or copper-based fungicides (see Table 1 for specific products). Multiple applications may be required. Apply all chemicals according to the directions indicated on the label.

Cercospora Leaf Spot: Leaf spots caused by Cercospora lythracearum may appear on crape myrtles and are caused by the fungus Cercospora species. This disease typically occurs during periods of warm, moist weather. Yellow spots (⅛ to ¼ inch diameter) appear on the upper leaf surface with white-grey sporulation of the fungus on the lower leaf surface. The disease can result in almost complete defoliation of the plant in late summer and fall in susceptible cultivars.

Prevention & Treatment: Select resistant varieties for new plantings. The varieties ‘Fantasy,’ ‘Tonto,’ ‘Tuscarora,’ ‘Tuskegee,’ and ‘Velma’s Royal Delight’ have exhibited resistance to Cercospora leaf spot in field trials. The amount of resistance may vary from location to location and may depend on particular environmental conditions. Provide good air circulation and avoid overcrowding plants. If the disease is severe enough to warrant using chemicals for control, thiophanate-methyl or myclobutanil as used for powdery mildew will control Cercospora leaf spot (see Table 1 for specific products). Apply all chemicals according to directions on the label.

Insects & Other Pests

Very few insects are pests of crape myrtle. In South Carolina, the most common insect pest is the crape myrtle aphid (Sarucallis kahawaluokalani), found on the leaves and twigs of crape myrtle. Crape myrtle aphids feed only on crape myrtle trees.

Japanese beetle (Popillia japonica) is also a pest and feeds on both leaves and flowers. In addition to crape myrtle, it will feed on nearly three hundred different plant species.

Crape Myrtle Diseases & Insect Pests (2)

A heavy infestation of aphids on the underside of a leaf.
Image from John Herbert, University of Florida

(Video) Kill Aphids and Mold on Plants and Crepe Mrytles

Crape Myrtle Aphids: Crape myrtle aphids are pale yellowish-green in color with black spots on the abdomen. They vary in length from 1/16 to ⅛ inch long. They overwinter (survive the winter) as eggs, which hatch in the spring. During the growing season, females give birth to live young. Since it takes about 10 days to reach maturity, several generations are produced each growing season. At the end of the growing season, females produce eggs that overwinter.

Aphids feed by inserting their mouthparts into tender new leaves from which they suck plant sap. Plant sap has a high sugar content. When they feed, the aphids excrete large amounts of sugary liquid called honeydew. With a large aphid population, the honeydew can completely coat leaves. The honeydew serves as food for the sooty mold fungi (Capnodium species), as well as various insects, including ants, wasps, and flies.

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 leaf distortion. Buds, branch tips, and flowers can also be affected by feeding.

Control: The following crape myrtle hybrids (Lagerstroemia indica x fauriei) have moderate resistance to aphids: ‘Muskogee,’ ‘Natchez,’ ‘Tuscarora,’ ‘Acoma,’ ‘Tuskegee,’ ‘Hopi,’ ‘Pecos,’ ‘Zuni,’ ‘Biloxi,’ ‘Miami,’ ‘Wichita,’ ‘Apalache,’ ‘Comanche,’ ‘Lipan,’ ‘Osage,’ ‘Sioux,’ ‘Yuma,’ ‘Caddo,’ ‘Tonto,’ ‘Choctaw,’ and ‘Fantasy.’ Consider using these in new plantings.

Several predators feed on the crape myrtle aphid. These include ladybird beetles (ladybugs) and their larvae (immature forms), green lacewings and their larvae, hover fly maggots, parasitic wasps, and entomophagous (insect feeding) fungi. As much as possible, these natural predators should be allowed to reduce aphid populations. In addition, many aphids can 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. In addition, using insecticides means that beneficial predators will also be killed. If it is determined to be absolutely necessary, various insecticides are labeled for use by homeowners against aphids on crape myrtles. These include insecticidal soap, horticultural oil, pyrethrins, neem oil, permethrin, cyfluthrin, cyhalothrin, acephate, or malathion. Soil drenches of imidacloprid in the spring will control aphids and last longer within the plant to prevent future infestations by aphids and other insect pests (see Table 1 for specific products). As with all pesticides, read and follow all label instructions and precautions.

Japanese Beetles: Adult Japanese beetles are about ½ inch in length and coppery-brown in color with metallic green heads. They emerge from the soil and feed from May to August. They lay their eggs in the soil. Grubs hatch from the eggs and feed on grass roots. As the weather cools, the grubs move more deeply into the soil to overwinter.

Both adult beetles and their larvae (grubs) can seriously damage plants as a result of their feeding. Adult Japanese beetles eat flowers and skeletonize leaves (eat leaf tissue between the veins, resulting in a lacy skeleton remaining). The grubs feed on the roots of plants, especially on the roots of grasses.

(Video) How do I control black mold and aphids on my Crape Myrtles?

Control: Multiple approaches are necessary for controlling Japanese beetles. Adults can be handpicked and drowned in a pail of soapy water. Japanese beetle traps are available commercially or can be homemade. They may be effective at reducing adult populations.

Keep traps at least 50 feet from the crape myrtle tree, or you may create more of a problem by attracting them to the area. Milky spore, Paenibacillus popilliae, is a disease-causing bacterium that is effective against grubs of Japanese beetles that live in the soil and feed on turfgrass roots, but not the adults. It is commercially available for homeowner use. Many products containing neem oil, cyfluthrin, permethrin, cyhalothrin, or acephate are labeled for use by homeowners against Japanese beetles on crape myrtles. Soil drenches of imidacloprid in the spring will greatly reduce damage by Japanese beetles and last longer within the plant to prevent future infestations by additional pests (see Table 1 for specific products). As with all pesticides, read and follow all label instructions and precautions.

Crapemyrtle Bark Scale: This crape myrtle pest is a more recent arrival. For information on this insect pest and control measures, please see HGIC 2015, Crapemyrtle Bark Scale.

Crape Myrtle Diseases & Insect Pests (3)

Sooty mold completely covers these crape myrtle leaves.
Image from John Herbert, University of Florida

Other Problems

Sooty Mold: Leaf and stem surfaces are covered with a black sooty substance, causing them to appear black and dirty. Sooty mold indicates that there is an insect problem on the plant. These common molds are caused by fungi that grow on the sugary substance called honeydew, produced by various insects that suck sap from the plant. Aphids, scales, mealybugs, and whiteflies most commonly cause this problem.

Prevention & Treatment: Sooty molds are unsightly but are relatively harmless since they do not directly attack the plant. Controlling the insect problem can reduce excessive amounts of sooty mold. Reduce aphid numbers by allowing beneficial insects, such as lady beetles, to inhabit the plant. Aphids can be removed from the plant with a strong spray of water.

(Video) Insects on Crape Myrtles | Aphids on Crape Myrtles | Black Mold on Crape Myrtles

Although not necessary, sooty mold can be washed from the leaves by spraying foliage with a dish soap solution (4 ounces per gallon of water), waiting three to four minutes, and then rinsing the foliage with a strong stream of water.

Crape Myrtle Diseases & Insect Pests (4)

These harmless lichens are growing on an older crape myrtle.
Karen Russ, ©2007 HGIC, Clemson Extension

Lichens: A lichen is an unusual organism composed of a fungus and a green alga and/or a cyanobacterium living together in the same body. Lichens often appear as green to gray-green leafy or crusty growths on the trunks or branches of plants. Typically, they occur in abundance on plants that are declining in health or vigor. They are harmless to the plant and are in no way responsible for the poor health of the plant. Less vigorous plants tend to be more open with less foliage, which increases sunlight penetration and subsequent lichen growth.

Prevention & Treatment: Controls are not necessary. Lichens will gradually disappear if the health of the plant is restored. However, there are a few consumer products with lichen control listed on their labels. They are:

  • Bonide Moss Max RTS
  • Bayer BioAdvanced 2-in-1 Moss & Algae Killer & Cleaner RTS
  • Scott’s MOSS-EX 3-in-1 RTS

All products say to apply only to the hardened bark of trees. They should be applied only to the bark and with no foliar contact. These products do not say for use on shrubs. All three are identical and contain 22.11% potassium salts of fatty acids. RTS means they are in a hose-end sprayer bottle.

Table 1. Insecticides & Fungicides for Crape Myrtle Insect Pest & Disease Control.

(Video) Treating Crape Myrtle Bark Scale – Family Plot

Insecticides & FungicidesExamples of Brand Names & Products
AcephateBonide Systemic Insect Control Concentrate
Copper-based FungicidesBonide Liquid Copper Concentrate
Bonide Copper Fungicide
Camelot O Fungicide/ Bactericide Concentrate
Monterey Liqui-Cop Fungicide Concentrate
Natural Guard Copper Soap Liquid Fungicide Conc.
Southern Ag Liquid Copper Fungicide Concentrate
CyfluthrinBayer BioAdvanced 24 Hour Lawn Insect Killer RTS1
Bayer BioAdvanced Complete Insect Killer for Soil &Turf I RTS1
Bayer BioAdvanced Insect Killer for Lawns RTS1
Horticultural OilBonide All Seasons Spray Oil Concentrate
Ferti-lome Horticultural Oil Spray Concentrate
Monterey Horticultural Oil Concentrate
Safer Brand Horticultural & Dormant Spray Oil Conc.
Southern Ag Parafine Horticultural Oil
Summit Year Round Spray Oil Concentrate
ImidaclopridBayer BioAdvanced 12 Month Tree & Shrub Insect
Control Landscape Formula (soil drench)
Bonide Annual Tree & Shrub Insect Control with
Systemaxx (soil drench)
Ferti-lome Tree & Shrub Systemic Insect Drench
Martin’s Dominion Tree & Shrub Insecticide (soil drench)
Monterey Once A Year Insect Control II (soil drench)
Insecticidal SoapNatural Guard Insecticidal Soap Concentrate
Safer Brand Insect Killing Soap Concentrate
Cyhalothrin, Lambda or GammaMartin’s Cyonara Lawn & Garden Concentrate; & RTS1
Spectracide Triazicide Insect Killer for Lawns &Landscapes Conc.; & RTS1
MalathionBonide Malathion 50% Insect Control Concentrate
Gordon’s Malathion 50% Spray Concentrate
Hi-Yield 55% Malathion Insect Spray
Martin’s Malathion 57% Concentrate
Ortho MAX Malathion Insect Spray Concentrate
Southern Ag Malathion 50% EC
Spectracide Malathion Insect Spray Concentrate
Tiger Brand 50% Malathion Spray
Milky SporeSt. Gabriel Organics Milky Spore Granular Grub Control
MyclobutanilSpectracide Immunox Multi-Purpose Fungicide Conc.
Ferti-lome F-Stop Lawn & Garden Fungicide Concentrate
Monterey Fungi-Max (Concentrate)
Neem OilBonide Rose Rx 3-in-1 Concentrate
Bonide Neem Oil Concentrate
Concern Garden Defense Multi-Purpose Spray Conc. Ferti-lome Rose, Flower & Vegetable Spray Concentrate
Garden Safe Fungicide 3 Concentrate
Garden Safe Neem Oil Extract Concentrate
Monterey 70% Neem Oil Fungicide/Insecticide/Miticide
Natria Neem Oil Concentrate
Natural Guard Neem Concentrate
Safer Brand Neem Oil Concentrate
Southern Ag Triple Action Neem Oil Concentrate
PermethrinBonide Eight Insect Control Vegetable Fruit & Flower
Concentrate
Bonide Total Pest Control – Outdoor Concentrate
Bonide Eight Yard & Garden Ready To Spray (RTS1)
Hi-Yield Indoor/Outdoor Broad Use Insecticide Conc.
Southern Ag Permetrol Lawn & Garden Insecticide Conc.
Tiger Brand Super 10 Concentrate
PropiconazoleBanner Maxx Fungicide
Bonide Infuse Systemic Disease Control Conc.; & RTS1
Ferti-lome Liquid Systemic Fungicide II Concentrate
Martin’s Honor Guard PPZ
Quali-Pro Propiconazole
PyrethrinBonide Pyrethrin Garden Insect Spray Concentrate
Monterey Bug Blaster-O
PyGanic Crop Protection EC 1.4
Southern Ag Natural Pyrethrin Concentrate
Thiophanate-methylCleary’s 3336-WP Turf & Ornamental Fungicide
Southern Ag Thiomyl Systemic Fungicide
Note: Control of diseases and insects on large trees is usually not feasible since adequate spray coverage of the foliage with a pesticide cannot be achieved.
1RTS = Ready to Spray (a hose-end sprayer)

Pesticides are updated annually. Last updates were done on 2/21 by Joey Williamson.

Originally published 05/99

If this document didn’t answer your questions, please contact HGIC at hgic@clemson.edu or 1-888-656-9988.

FAQs

What can I spray on my crepe myrtle? ›

Horticultural or neem oil are excellent options for Crape Myrtle. Both will control pests but won't harm other beneficial insects. Aphids, scale insects, and beetles have natural predators that can help control their populations, too. Chemicals are an option for severe infestations but should be used with care.

What is the white stuff on the branches of my crepe myrtle? ›

The weird, white stuff is a fungus called powdery mildew. Its spores are everywhere, but they don't germinate unless the conditions are right. And that's what crepe murderers have helped to do this year.

How do you get rid of black spots on crepe myrtles? ›

Treatment: Although not necessary, sooty mold can be washed from the leaves by spraying foliage with a dish soap solution (4 ounces per gallon of water), waiting three to four minutes, and then rinsing the foliage with a strong stream of water.

What is the black stuff on my crepe myrtle leaves? ›

Most likely, the strange black film on your crepe myrtle is due to a plant condition called sooty mold. It's caused by certain types of fungi growing on sugary secretions (called honeydew) left behind by garden insects. This leaves a dark gray or blackened powdery texture over the affected area of the plant.

How do I get rid of spider mites on my crepe myrtle? ›

Heavy spider mite populations damage myrtle foliage and spread to nearby plants. Insecticidal soap or horticultural oil, sprayed on the pests and over the plant, kills the pests on contact. They can be used through the growing season and are also effective on other crape myrtle pests such as thrips and aphids.

What do aphids on crepe myrtles look like? ›

Crapemyrtle aphids are small, fragile insects around 116 inch long. They are pale yellowish-green with black spots on the abdomen. Crapemyrtle aphids are easy to distinguish from other aphids that occasionally infest crapemyrtle. Winged adults have dark tipped antennae and two double-pronged humps on the back.

Is Epsom salt good for crepe myrtles? ›

Epsom salt is often used with plants that like magnesium, like tomatoes and roses. It can be beneficial for Crape Myrtles in some cases. However, if your soil already has enough magnesium, the added Epsom salt may do more harm than good.

How do I get rid of aphids on my crepe myrtle? ›

How do I control black mold and aphids on my Crape Myrtles?

How do I get rid of whiteflies on my crepe myrtle? ›

A simple solution made from liquid dish soap and water will kill adult whiteflies without harming plants. Add 1 tablespoon of liquid dish soap to 1 gallon of water and mix well. Pour the solution into a plastic spray bottle and spray it on all infested plants, saturating the leaves' upper and undersides and the stems.

What is the black stuff on the trunk of my crepe myrtle? ›

The black is caused by a saprophytic fungus called black sooty mold that grows on the sugary exudate that is excreted from the scale insects. While the black mold is not harmful to the tree, it sure makes it look unsightly.

What is a natural way to get rid of sooty mold? ›

Home remedies that work include baking soda sprays (1 tablespoon of baking soda and 1 teaspoon of insecticidal or dish soap-do not use detergent-in a gallon of water. Spray every 7 to 14 days) and solutions of milk (one part milk to two parts water, sprayed every 7 to 14 days).

How do you treat Cercospora leaf spots on crepe myrtles? ›

Use a fungicide made specifically for ornamental plants and alter the type used to avoid building up a resistance. For effective control of Cercospora leaf spot with a fungicide, begin applications when leaves begin to appear in the spring and continue applying a fungicide as needed.

How do you apply neem oil to crepe myrtle? ›

Treating Crepe Myrtles with Neem Oil Extract #CrepeMyrtles ... - YouTube

What causes aphids on Crepe Myrtles? ›

Aphids tend to be more problematic when trees have excessive nitrogen, so avoid overfertilizing. Predatory insects such as lady beetles and green lacewings often help keep aphid populations smaller than they otherwise would be.

What kills spider mites instantly? ›

Use Rubbing Alcohol. Kill spider mites by combining a mixture of 1 cup of rubbing alcohol and 4 cups of water, then spray the solution on your plants. Cover the stems, flowers, and foliage thoroughly. Rubbing alcohol kills spider mites by dehydrating them.

How do I know if I have spider mites? ›

There are three key signs of a spider mite infestation: Tiny white or yellow spots on the top of tree leaves or needles. Silky webs woven around tree leaves and stems. A yellow or bronze appearance in one or many areas of the tree (this happens with a heavy infestation)

How do you get rid of spider mites once and for all? ›

Rubbing alcohol: The rubbing alcohol you have around the house also can kill spider mites. Soak cotton balls in rubbing alcohol and wipe across the foliage of infested houseplants. Let either the dish soap or rubbing alcohol sit on the plants for a few hours, and then rinse the leaves thoroughly with water.

What insecticide kills aphids? ›

The following pesticides all control aphids, and may help kill aphids on plants in your garden: Bonide Insect Control Systemic Granules. Bonide Systemic Houseplant Insect Control. BioAdvanced Systemic Plant Fertilizer and Insecticide with Imidacloprid.

How do you treat crepe myrtle scales? ›

How do I treat for crapemyrtle bark scale? Systemic insecticides work very well to control the bark scale, but the timing is most effective when applied in late winter/early spring. If you are just now spotting the problem, you can clean off the trunk with warm, soapy water to remove the black sooty mold.

Is neem oil safe for crepe myrtles? ›

Crape myrtle have many overwintering insects and diseases that can be controlled by spraying thoroughly until runoff with Neem Oil. This product is a safe, non-toxic pesticide for your garden and landscape that is also friendly to the environment and still effective.

Is Miracle Grow good for crape myrtles? ›

Using these types of fertilizers will cover your bases if the soil in your area is deficient in a certain element or trace mineral. The easiest to use and most well known fertilizer is Miracle Gro. However, if you have many Crape Myrtles you wish to fertilize, using Miracle Gro can become expensive.

Is coffee grounds good for crepe myrtles? ›

The answer is yes! Coffee grounds make an excellent ground mulch, especially for acid-loving plants.

How do I bring my crepe myrtle back to life? ›

How To Fix Crepe Murder | Southern Living - YouTube

What do aphids look like on a plant? ›

Quick Facts About Aphids

Aphids may be black, red, green, brown, or yellow. Their color is also affected by what they eat. Aphids produce a sticky residue called “honeydew,” which drips off of plants and attracts ants. Honeydew can also produce a mold around the base of the plant that may kill the plant.

How do you make insecticidal soap? ›

Can I make my own insecticidal soap? Certainly! By mixing 2.5 tablespoons of vegetable oil and 2.5 tablespoons of pure liquid soap with 1 gallon of distilled water, you'll have a whole gallon of insecticidal soap for safely spraying plants in flowerbeds or the vegetable garden.

How do you get rid of a white fly infestation? ›

Always start with blasting whiteflies (as with aphids and many other insect pests) with your watering hose or a spray bottle. This will cause them to scatter and will dislodge nymphs and eggs to some extent. Consider spraying your plants' leaves with an insecticidal soap, following the directions on the packaging.

What causes white fly infestation? ›

As much as your plants like nitrogen-rich fertilizers, whiteflies like your nitrogen-rich plants, as well. Excessive nitrogen fertilization can cause frequent infestations. While nitrogen can boost the vitality of your plants, over-fertilizing your garden can attract whiteflies, leading to more frequent infestations.

What does whitefly look like? ›

Whiteflies are tiny (about 1/12th of an inch) triangular-shaped flying insects with a pale yellow or white body and white wings. Some varieties may look a bit different, like the bandedwinged whitefly, that has subtle stripes on its wings.

What causes bark scale on crepe myrtle? ›

The most likely culprit is a scale insect found in China, Japan, and Korea. In its na- tive range, this scale, tentatively identified as crape myrtle bark scale (CMBS, Eriococ- cus lagerstroemia), feeds on crape myrtles and pomegranates.

Why does my crepe myrtle look burnt? ›

Burned foliage, a result of adverse growing conditions. A: Burned edges of leaves can be caused by several things including too much fertilizer, lack of water, root diseases or too much water. I suspect the problem is directly related to the amount of water your crape myrtle is receiving.

How do you know when a crepe myrtle is dying? ›

Signs that your Crepe Myrtle is dying or dead

Crepe Myrtles have thin bark, which you can scratch with your fingernail. You can do this to check the health of your tree. Tree care professionals call this the “scratch test.” If the bark underneath is green, your tree is still alive.

What kills mold instantly? ›

Hydrogen peroxide kills mold effectively on materials such as clothing, floors, bathroom fixtures, walls and items such as kitchen appliances. Pour 3% concentration hydrogen peroxide into a spray bottle. Spray the moldy surface completely to saturate the area with hydrogen peroxide.

Can I leave vinegar on mold overnight? ›

To safely and effectively clean a small area of mold, ServiceMaster advises the following: Add full-strength white distilled vinegar to a spray bottle and spray it on the mold. Let it sit for at least an hour before wiping away mold.

What insects cause black sooty mold? ›

A number of insects can produce the honeydew sooty mold needs for growth. These insects include aphids, leafhoppers, mealybugs, psyllids (including eucalyptus redgum lerp psyllid), soft scales, and whiteflies (Table 1). Both the immature and adult stages of these insects produce honeydew while feeding.

Why are the leaves on my crepe myrtle turning yellow and falling off? ›

Impurities in water. Crepe myrtles are extremely sensitive to impurities in the water they are growing in. The leaves will turn yellow, then brown and fall off. The problem is that these impurities can be hard to identify.

What causes Cercospora leaf spot on crape myrtles? ›

The Cercospora leaf spots form on crape myrtle and other types of plants due to water drops from rain or irrigation that sit on leaves during hot and humid conditions. This is especially true in large plant nurseries and residential or commercial landscapes that use overhead irrigation frequently.

Do you spray neem oil on soil or leaves? ›

When spraying a plant with neem oil—either as a bug treatment or preventive measure—it's important to coat both the tops and bottoms of leaves since bugs love to hang out on the underside of foliage. You should also lightly coat the stems and soil, just in case any critters have made their way to those areas.

How long does it take for neem oil to work? ›

You are, on the other hand, making your plant very unattractive for insects and pests. Keep in mind that Neem Oil doesn't work right away. It takes a few days, usually about 3 to 4 days, and a few treatments before you start to see the results you're looking for.

Can neem oil burn plants? ›

Regardless of the type of plant being treated, neem oil can damage plants by burning their foliage. Do not use on recent transplants or otherwise stressed plants. Though plants must be completely covered with neem oil for the pesticide to be effective, it is a good idea to test the product on a small area first.

What can I spray on my crepe myrtle for bugs? ›

If it is determined to be absolutely necessary, various insecticides are labeled for use by homeowners against aphids on crape myrtles. These include insecticidal soap, horticultural oil, pyrethrins, neem oil, permethrin, cyfluthrin, cyhalothrin, acephate, or malathion.

When should I use neem oil? ›

Neem oil works as a preventative method as well as pest control for an existing infestation. Use neem oil during the morning or evening hours. Avoid using neem oil during the middle of the day, as the combination of neem oil and direct sunlight can burn the plants.

What is insecticidal soap for plants? ›

Insecticidal soap is made with potassium salts of fatty acids, and it's commonly used by gardeners to curb infestations of insects and pests on their plants. Soap sprays are effective for soft-bodied insects such as mealybugs and aphids. Insecticidal soap does not harm the plants.

How do you get rid of mildew on crepe myrtles? ›

The best way to manage powdery mildew on crapemyrtles is to plant resistant cultivars. You should plant them in full sun and in open areas with good air circulation. If established crapemyrtles are infected, prune them to increase air circulation. Remove the small, twiggy growth below and within the canopy.

How do I keep aphids off my crepe myrtles? ›

Treat crepe myrtles and all plants under its canopy weekly with neem oil. This kills aphids on contact, and protects against sooty mold, which is more damaging.

What causes powdery mildew on crepe myrtles? ›

Powdery mildew spores are disseminated by wind. Under favorable conditions, infection may occur as few as 3 to 5 days after the spore lands on the crape myrtle. Powdery mildew spores can germinate and infect crape myrtle in the absence on free water on the plant tissue, as long as there is adequate humidity in the air.

Is Epsom salt good for crape myrtles? ›

So as long as the plant is producing healthy branches and buds each spring, it will bloom. The most common culprits for a crepe myrtle not blooming are improper pruning, lack of sunlight, or a nutritional imbalance in the soil. Epsom salt is often recommended as a magnesium supplement.

Which fungicide is best for powdery mildew? ›

Chlorothalonil has been the primary protectant fungicide used for powdery mildew. Copper fungicides and sulfur have also been used.

How do I get rid of powdery mildew? ›

Baking soda has been proved by many gardeners to be effective in treating powdery mildew. Mix 1 teaspoon baking soda in 1 quart of water. Spray plants thoroughly, as the solution will only kill fungus that it comes into contact with. Milk spray is another effective home remedy.

What causes black bark on crepe myrtles? ›

CMBS might be found anywhere on crapemyrtles, and often appears near pruning sites and branch crotches of more mature wood. Often times, the first sign of CMBS is the black sooty mold on the tree bark. This may be misleading since a more common and easy to control pest, aphids, can also cause sooty mold.

What insecticide kills aphids? ›

The following pesticides all control aphids, and may help kill aphids on plants in your garden: Bonide Insect Control Systemic Granules. Bonide Systemic Houseplant Insect Control. BioAdvanced Systemic Plant Fertilizer and Insecticide with Imidacloprid.

Is neem oil safe for crepe myrtles? ›

Crape myrtle have many overwintering insects and diseases that can be controlled by spraying thoroughly until runoff with Neem Oil. This product is a safe, non-toxic pesticide for your garden and landscape that is also friendly to the environment and still effective.

What do aphids look like on a plant? ›

Look for misshapen, curling, stunted, or yellowing leaves. Be sure to check the undersides of leaves; aphids love to hide there. If the leaves or stems are covered with a sticky substance, that is a sign that aphids may have been sipping sap.

Will powdery mildew go away on its own? ›

The Basics of Powdery Mildew

They need the plant's nutrients to survive. And unlike most types of fungi, they cause more severe cases of disease in warm, dry weather. A mild case may go away on its own.

What causes aphids on crepe myrtles? ›

Aphids tend to be more problematic when trees have excessive nitrogen, so avoid overfertilizing. Predatory insects such as lady beetles and green lacewings often help keep aphid populations smaller than they otherwise would be.

How do you apply neem oil to crepe myrtle? ›

Treating Crepe Myrtles with Neem Oil Extract #CrepeMyrtles ... - YouTube

Is Miracle Grow good for crape myrtles? ›

Using these types of fertilizers will cover your bases if the soil in your area is deficient in a certain element or trace mineral. The easiest to use and most well known fertilizer is Miracle Gro. However, if you have many Crape Myrtles you wish to fertilize, using Miracle Gro can become expensive.

Is coffee grounds good for crepe myrtles? ›

The answer is yes! Coffee grounds make an excellent ground mulch, especially for acid-loving plants.

How do I bring my crepe myrtle back to life? ›

How To Fix Crepe Murder | Southern Living - YouTube

Videos

1. How to treat for crapemyrtle bark scale
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2. 2016 07 20 11 06 Crapemyrtle pests disease disorders
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4. Crape Myrtle Bark Scale | Volunteer Gardener
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5. How to treat Crape Myrtle Scale
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6. Crape Myrtles – Family Plot
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