The white bugs on your crepe myrtle are almost certainly crapemyrtle bark scale, an invasive pest that has spread rapidly across the southern and mid-Atlantic United States since first appearing in Texas around 2004. These insects cluster on branches and trunks as small white or grayish felt-like masses, and if you crush one, it produces a distinctive pink or lavender fluid. That pink smear is the simplest way to confirm what you’re dealing with.
What Crapemyrtle Bark Scale Looks Like
The white coating you see is actually a waxy covering the female insects build around themselves and their eggs. Underneath that white shell, adult females are dark red with short legs and threadlike mouthparts they use to pierce bark and feed on sap. The egg sacs contain pink to reddish-purple eggs. Male nymphs tend to feed on leaves rather than bark, and adult males are tiny, gnat-like winged insects you probably won’t notice.
The pests favor twig crotches and the undersides of branches, but heavy infestations spread across the trunk and can make the entire tree look white or crusted. You’ll often spot them first on the smooth bark that crepe myrtles are known for.
Signs Your Tree Is Infested
Beyond the visible white masses, the most obvious symptom is black sooty mold. As the scales feed on sap, they excrete a sticky, sugar-rich waste called honeydew. A dark fungus grows on this honeydew, coating branches, trunks, and even nearby surfaces in a black film. The sooty mold itself doesn’t directly harm the tree, but it blocks sunlight from reaching bark and leaves.
Crapemyrtle bark scale won’t kill your tree. It does, however, reduce both the number and size of blooms, which is the whole reason most people planted the tree in the first place. Heavily infested trees look noticeably less vigorous, with sparse flowering and that characteristic blackened appearance.
Life Cycle and Timing
Understanding the life cycle helps you time your treatment. The insects overwinter as nymphs feeding through the bark. In spring, eggs are laid in late April and hatch about three weeks later in early May. The tiny pink crawlers that emerge are the most vulnerable life stage. They crawl out of the egg sac and settle onto bark, especially near twig crotches, where they begin feeding and building their waxy covering.
This first generation matures during summer and produces a second round of eggs that hatch in September. So you’re dealing with two waves of crawlers per year: one in May and one in early fall. Late spring and late summer are the two best windows for spraying.
Manual Removal and Cleaning
Start with physical removal. Scrub infested areas with warm, soapy water and a stiff-bristled brush. This won’t eliminate an infestation on its own, but it reduces the population and strips away the waxy coating that protects the insects from sprays and oils. Scrubbing also removes the black sooty mold, which improves the tree’s appearance immediately.
Heavily infested branches can be pruned out and destroyed. If you live in a colder area where crepe myrtles die back to the ground each winter, cutting them to the roots may be enough to solve the problem entirely, since the scales don’t overwinter on roots or in the soil.
Sprays for Crawlers
Horticultural oil and insecticidal soap are effective against crawlers and young nymphs, the small mobile stages that haven’t yet built up their protective coating. Because the two generations overlap and timing varies by region, spraying throughout the warm months is the practical approach. Plan on multiple applications rather than a single treatment. Scrubbing off the mature scales first makes these sprays significantly more effective on whatever insects remain.
A dormant oil application after all the leaves have fallen in late autumn can also kill many overwintering crawlers and adults, though it won’t get them all. Think of dormant oil as one layer in a broader strategy rather than a standalone solution.
Soil-Applied Systemic Treatments
The most effective option for moderate to heavy infestations is a soil-applied systemic insecticide. You mix the product with water and pour it around the base of the tree as a drench (rake mulch away first so the solution reaches the soil). The tree’s roots absorb the chemical and distribute it through the entire vascular system. When the scales feed on sap, they ingest the insecticide.
For best results, apply during the early growing season, late March through May, to target the first generation of nymphs. You can treat any time the tree is actively leafed out, but earlier applications give the product time to move through the tree before peak crawler activity. Apply only one treatment per year.
The active ingredients that have proven most effective all belong to the neonicotinoid class. Products sold for homeowner use are widely available at garden centers, typically labeled for tree and shrub insect control. Professional applicators can inject treatments directly into the soil, which avoids the need to clear mulch.
Pollinator Concerns With Systemics
Neonicotinoid soil drenches come with an important tradeoff. Research has shown that soil-applied treatments can persist in plant nectar for up to 230 days after application. Crepe myrtles bloom heavily in summer and are visited by bees, butterflies, and other pollinators. If you apply a systemic in spring, the active ingredient will be present in the flowers when pollinators arrive.
To reduce this risk, some extension programs recommend applying systemic treatments in late summer or fall, after bloom has finished, rather than in spring. The product will still be taken up by the tree and will target overwintering nymphs and early crawlers the following spring. This timing won’t protect the current season’s blooms as effectively, so it’s a judgment call between faster scale control and pollinator safety.
What to Expect After Treatment
One detail that catches people off guard: dead scale insects stay on the tree. Even after a successful treatment, the white waxy masses and the dark bodies underneath remain attached to the bark. They’re no longer feeding or spreading, but your tree won’t look “clean” right away. You can scrub them off with soapy water and a brush for cosmetic improvement.
The sooty mold will gradually weather away on its own once the honeydew source is gone, though washing it off speeds the process. Bloom size and quantity should improve the following season as the tree recovers from the feeding pressure. In areas with ongoing infestations nearby, reinfestation is possible, so check your trees each spring for new white masses near twig crotches.
Natural Predators
Several beneficial insects feed on crapemyrtle bark scale. Twice-stabbed lady beetles (small black ladybugs with two red spots) have been observed eating the scales in the United States, and at least 16 species of parasitoid wasp attack the pest worldwide. The limitation is that these predators typically arrive too late in the season to keep populations in check on their own. They’re helpful allies, but not a reliable standalone control. Avoiding broad-spectrum insecticide sprays on the tree canopy helps preserve whatever natural enemies are present.