Saturday, May 25, 2024

How To Treat Black Mold On Crepe Myrtles

How To Spray Neem Oil On Crepe Myrtle Trees

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

To spray crepe myrtles trees, a pump-action sprayer that has a long reach wand will be needed.

You will need a neem oil concentrate diluted to the ratio explained in the instructions that come with the bottle.

When spraying, the spray should be directed to the underside of leaves as that is where aphids do most of their feeding. And why their excrements hit lower leaves and all the plants under them.

Use a diluted strength neem oil soak once weekly. Daily though, hit the plant with a forceful jet spray of water directed at the underside of leaves to knock as many aphids off the plant as possible.

For every aphid that remains, they can produce up to 5 wingless offspring daily. That is why a daily hosing down is essential.

Weekly treatments of neem oil are needed to hit the stray aphids that manage to survive your artificial rainstorm.

The combo approach will eventually get rid of aphids on crepe myrtle trees and save every plant under it from shutting down because of sooty mold.

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.

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

  • Honeydew
  • Ants on the Tree chasing the honeydew
  • Drooping Leaves
  • 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.

Care For A Crepe Myrtle Tree

Crepe myrtle is a popular, easy to grow tree in the right setting. These Southern favorites provide shade, and feature attractive, peeling bark and are easy to care for. They flourish in U.S. Department of Agriculture plant hardiness zones 7a through 9a. But if you live in a colder climate, there are many hybrid crepe mytles that can survive in zone 6, and some can survive in zone 5 if they’re planted in a protected area. Crepe myrtle needs to be watered regularly for the first two months. Wait a day or two to water if the soil feels cool and moist. Once the roots are established, the tree rarely requires supplemental water. However, crepe myrtle benefits from an occasional watering during hot, dry weather, especially while the tree is blooming. To determine the amount of fertilizer for an established tree, measure the ground under the widest part of the canopy, or top of the tree, then provide 1/2 pound of fertilizer for every 100 square feet. Healthy crepe myrtle is relatively disease-resistant. Pruning depends on the desired size and shape of the tree. Otherwise, prune sparingly to maintain the tree’s natural shape. Shorten excessively long outer branches.

  • Crepe myrtle is a popular, easy to grow tree in the right setting.
  • However, crepe myrtle benefits from an occasional watering during hot, dry weather, especially while the tree is blooming.

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Identification And Symptoms Of Sooty Mold Fungus

Identifying sooty mold fungus is fairly easy. If you notice a dark gray to black sooty coating on the foliage and fruit of a plant, shrub, or tree, chances are, sooty mold fungus is the culprit. If you notice the presence of honeydew on the leaves, branches, and twigs of one of your plants, you may have time to keep the fungus from forming. If you notice the presence of aphids, mealy bugs, or other tiny insects on your plant, you might even be able to prevent the spread of honeydew by treating the plant for pests before they have a chance to coat the leaves with their sugary-sweet substance.

The symptoms of sooty black mold are simple and easy to see. The affected plants become covered in a sooty layer of gray or black grime. The mold is powdery and sticky and the layer is relatively thick. The dark color and the thickness of the fungal growth blocks photosynthesis, which keeps the chlorophyll from functioning properly, which can eventually cause the leaves to wither and die. Though the leaves of affected plants are sometimes casualties of sooty mold fungus, the plants, shrubs, and trees live on long after the fungal growth has come and gone. Soot can be removed, leaves can be regrown, and plants that have been the victims of major infestations can make miraculous recoveries with proper treatment.

Sooty Mold On Crape Myrtle Trees

How to Get Rid of Black Mold on Crepe Myrtles

Crape myrtle trees are large shrubs or trees that are hardy in USDA hardiness zones 6 through 9 and flower in late summer, says the Missouri Botanical Garden. Aphids, scale insects, whiteflies and mealybugs commonly infest the trees and excrete the honeydew that feeds sooty mold fungi. Check for the pests on stems, stem tips, flower buds and the undersides of leaves. Aphids are tiny, soft-bodied insects that live in clusters scales look like small, flat, rounded shells whiteflies are tiny, white flies and mealybugs are small, white, segmented insects covered in a crumbly wax coating.

The sooty mold fungi can also grow on resin or sap that oozes from wounds in the stems or bark. If the black residue is coating only one area of your tree, check for a cut or gash, advises the University of California Integrated Pest Management Program. Sooty mold that has appeared due to a wound should stop growing when the wound heals.

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Honeydew Sets The Stage For Black Sooty Mold

In the case of the crepe myrtle aphid, that can be in the tree feeding on the leaves, but the excrements can be dropping onto a hibiscus under it.

As the crepe myrtle aphid is species-specific, the colony will not migrate to the hibiscus plant, but the hibiscus will still show the symptoms of an infestation.

Ant trails and the fungal growth of black sooty mold.

White Substance On Crepe Myrtles

Sometimes, a fine white powdery substance may appear on parts of a crepe myrtle tree especially at the base. Often, this substance is a fungus or mold. You may also notice damage caused by insects like aphids. These substances arent just unpleasant to look at they also pose danger to the crepe myrtles. Like many other fungi, the mildew that forms on crepe myrtles trees thrives in damp, humid, shady and dark conditions. If it becomes too thick, the tree can become distorted or stunted and fail to flower.

Thats why treatment and prevention are so crucial. If you notice a fungus on a crepe myrtle, first remove dead and severely damaged branches, twigs and leaves. In addition, remove any sprouts from the base of the tree before they grow.

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Hosing And Spraying Organic Insecticides

Neem oil and insecticidal soaps are considered safe to use, however, they are not selective and can be harmful to beneficial bees.

When spraying organic insecticides, do it before the garden gets busy with beneficial bugs visiting. Either early morning and late evening when it is dry.

Soaps and oils should not be sprayed in hot temperatures anyway because oils magnify heat and that risks leaf burn.

The all-natural solution is a garden hose with a long reach wand to spray them off with water only.

Aphids are asexual that give birth to live young that are wingless. A strong enough blast of water to knock them into the soil is enough. They are too weak to get back onto the plant.

Given the tremendous amount of foliage on crepe myrtle trees though, it is inevitable that some will remain.

For those that do linger around, hit those with an organic insecticide.

Neem oil is effective as a contact insecticide, fungicide, and miticide.

In other words, if it does not kill on contact, it will affect the reproduction rate. Repeat applications are needed, however, with each treatment, breeding is slowed. That buys you time to get on top of the infestation.

How To Grow And Cultivate Cilantro

Q& A How do you remove black sooty mold from crape myrtle bark?

Cilantro needs full sun or light shade in southern zones since it bolts quickly in hot weather. It grows best in a well-drained, moist soil. Cilantro plants should be spaced about 6 to 8 inches apart. To harvest fresh cilantro all season, make successive sowings every 2 to 3 weeks starting in late spring.

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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 damage insects here or read about good lawn bugs.

About Sooty Mold Fungus

Sooty mold appears on plants and any objects or structures in the near vicinity of affected plants as a dark gray to black soot-like powdery coating that forms on the outer layer of plants, specifically on the branches, leaves, fruit, and anything else in the general area of the plant or plants in question. Sooty mold forms when fungal spores from ascomycete, capnodium and saprophytic fungi land on plants that are coated in a sugary, sticky substance that is excreted by common garden pests like aphids , mealybugs, white flies, and scale. The fungal spores stick to the honeydew left behind by these parasites, and sooty mold grows on the honeydew itself.

Though sooty mold doesnt grow directly on the plants, that doesnt mean that affected plants do not suffer from the growth of the fungus as it can quickly cover every branch and leaf on the entire plant with a thick, black, sooty layer. The growth doesnt hurt the plant directly, but the dark layer of sooty mold decreases photosynthesis, blocking the suns rays from the leaves, which subsequently start to wilt, wither, and eventually die if the growth isnt treated.

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How To Force Crepe Myrtles Bloom

If you have an older crepe myrtle that doesnt bloom the way you think it should, wait until after crepe myrtle bloom time and encourage the crepe myrtle bloom by pruning it carefully. If you trim away any of the dead branches that are inside the tree, this allows more sunshine and air to reach the tree.

Causes Of Crepe Myrtle Leaves Turning Black

How To Remove Black Sooty Mold ~ Garden Down South

Are your Crepe myrtles leaves turning black and unattractive?

This is a gardeners nightmare. The crepe myrtles bloom only once in spring so when the leaves start turning black its normal to get anxious. But this problem can be prevented and cured if you work on them tactically.

Sooty black mold, Adverse weather conditions, and Excess fertilization are the main three reasons why your crepe myrtle leaves are turning black.

No need to worry about this because this article will guide you through the easy solutions and preventions on how to treat the crepe myrtles black leaf.

So, without making any delay lets get started-

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Is Sooty Mold Harmful To Humans

Although it looks unsightly, sooty mold isn’t harmful to human health. If you touch or rub leaves, stems or bark that has that characteristic black coating, you’re left with dark smudges on your fingers. You’ll probably also feel the sticky honeydew that the mold is growing on. But there’s nothing to worry about. Just wash your hands with warm water and soap to remove the black marks.


The Effects Of Honeydew On All Plant Leaves

Aphids and similar sap-sucking pests pierce the leaves to feed on the sugary sap. The sap inside leaves is just like sugary water. It is a rich source of carbs for soft-bodied insects.

As Newtons law taught us: what goes in, must come out. Sap goes in, honeydew is the excrement.

This is a sticky substance that coats the leaves. Aphids do not poop where they feed. They drop their droppings to lower leaves away from their feeding ground.

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How Neem Oil Works

The neem oil disrupts the hormones of the insects preventingthem from molting and growing through their various stages. It also disruptstheir ability to lay eggs, therefore reproducing. I have also read that itmesses with their digestion, so they are sucking less on your plants.

Keep it mind it takes time, but only a few days depending onthe size of the infestation.

Ants Are A Garden Alarm

Black Sooty Mold on Crape Myrtles

A colony of aphids will leave loads of excrement on the leaves. Ants seek out that as their food source. Ants cannot and do not pierce into the leaves of plants. They eat the honeydew.

The relationship between ants and aphids is symbiotic. They rely on each other for survival.

Ants need the honeydew for food. Aphids benefit from their protection.

If the colony of aphids is big enough for an ant colony to warrant protecting them, they will fight off ladybugs and even lacewings to secure their food supply.

As the ants do not eat aphids, and the honeydew gets dropped, it lands on any plants under the tree canopy.

A trail of ants can signal that there are aphids or another sap-sucking insect nearby.

Since ants feed on the honeydew and not the sap, there will be ant trails beneath aphid colonies.

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What Causes Black Sooty Mold

Black sooty mold is actually an airborne fungi spore thatlatches on to the sweet sticky honeydew secreted by leaf and bark feedinginsects.

On Crepe Myrtles and most other plants the culprit here iseither sap sucking Aphids or Bark sucking Scale.

When they suck the sap, they excrete a thick gooey sugarysubstance called honeydew. The spores attach to this and grow, forming athickening black sticky surface which resembles soot from the result ofsomething burning. Hence the name: Sooty Mold.

If youve ever been under a crepe myrtle tree, and you fellsomething dripping on you like its raining, this is the aphids excretion.Nice, huh?

Aphids are not a welcome insect by any means, but there aregoing to be a few tolerable amounts on any crepe myrtle. The appearance ofsooty mold can sometimes be an indication that you have an over population ofaphids or Scale on your plant.

What To Do For Crepe Myrtle Sooty Mold

I had what I thought was sooty mold that formed late this past summer on one of my crepe myrtles, and was starting to spread to another one until fall arrived. It was a black substance that coated the leaves and trunks. The trees are small, and I am going to trim and shape them here in a few days for the desired shape I want them to grow into. Would right after this trimming be a good time to spray them for this mold? What should I use? Is dormant spray that I use on my peach trees ok?

Any and all non-condecending help will be greatly appreciated.

  • 16 years ago

    sooty mold along with aphids.

    I posted the query at the La/Miss forum, and got a response suggesting an organophosphate. Oh no, I’ll let ’em get eaten, I’m right on the water…

    But y’all are suggesting oils and soaps. So, can I get some advice regarding application and types?

    thanks in advance

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    Watch: What’s Wrong With My Crepe Myrtle 4 Common Problems

    Crepe myrtles come in all different colors and heights, so find the one that’s right for you. For vibrant summer color, few flowering plants can compete with the crepe myrtle. Just look around your neighborhood. Nearly every street in the South is lined with these blooming trees from mid-June to mid- August. There’s plenty to love about them: They grow almost anywhere, are easy to maintain, and are available in all shapes, sizes, and shades. When picking one for your yard, ask yourself: What color flowers do I want? Choose from red, white, purple, or pink. Is it cold hardy enough? This is key if you live in the Upper South. Is there plenty of sunlight? The more sun, the more flowers you’ll get. How big will it grow? Crepe myrtles have a reputation for growing fast. A larger one can overwhelm your landscape, which could result in the ill-advised pruning practice known as “crepe murder.” At right are four of our favorite selections.

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