Crepe Myrtle Bark Scale: Atlanta Diagnosis & Treatment Guide

What Is Crepe Myrtle Bark Scale?

Crepe myrtle bark scale (CMBS), Acanthococcus lagerstroemiae, is a relatively new invasive pest that has spread rapidly across the southeastern United States since its first detection in Texas in 2004. It arrived in Georgia around 2015 and has since been confirmed across metro Atlanta, affecting crepe myrtles in residential landscapes, commercial properties, and public spaces.

This scale insect feeds on the sap of crepe myrtles, extracting plant sugars and excreting sticky honeydew that coats bark, leaves, and surfaces beneath the tree. Black sooty mold fungi then colonize the honeydew, turning the once-beautiful bark into an unsightly black mess. While CMBS rarely kills crepe myrtles outright, it severely diminishes their signature ornamental appeal—the smooth, mottled bark and abundant summer flowers.

How to Identify Crepe Myrtle Bark Scale

• White, felt-like deposits: Look for small (1-2mm) white to grayish crusts on the bark, particularly in branch crotches, pruning wounds, and on the trunk. These are the scale insect colonies. When crushed, they release a pink blood-like fluid—a reliable identification test.
• Black sooty mold: Heavy sooty mold growth on bark, branches, and leaves gives the tree a blackened, dirty appearance. The mold grows on honeydew, not the plant tissue itself, but it blocks sunlight from reaching bark and leaves.
• Reduced flowering: Infested trees may produce fewer and smaller flower panicles than healthy specimens of the same cultivar.
• Honeydew drip: Cars, sidewalks, and patios beneath infested trees become sticky with honeydew, which also attracts ants and wasps.

Treatment Options

• Systemic insecticide: Soil drenches or trunk injections of dinotefuran (Safari) or imidacloprid provide effective systemic control. The insecticide is absorbed by the roots and moves through the vascular system to where scale insects are feeding. Dinotefuran is preferred for faster uptake.
• Horticultural oil: Winter applications of dormant oil smother overwintering scale. Summer applications of lightweight horticultural oil can reduce active populations.
• Bark washing: Scrubbing heavily encrusted bark with a soft brush and mild soapy water removes scale bodies and sooty mold, improving the tree's appearance while reducing the pest population.
• Encourage natural enemies: Lady beetles, particularly the twice-stabbed lady beetle (Chilocorus stigma), are effective predators of CMBS. Minimize broad-spectrum insecticide use that would harm these beneficial insects.

An integrated approach through a plant health care program combining systemic treatment, oil sprays, and natural enemy conservation provides the best long-term control.

Prevention Strategies

• Inspect before purchasing: CMBS spreads primarily through infested nursery stock. Carefully inspect crepe myrtles before buying—look for white scale on bark and sooty mold.
• Monitor existing trees: Check crepe myrtles in late winter and early spring for overwintering scale colonies before they begin reproducing.
• Avoid unnecessary pruning wounds: Scale insects often congregate on pruning wounds and damaged bark. Proper pruning that avoids leaving large wounds (and definitely avoiding "crepe murder" topping) reduces infestation sites.
• Report sightings: If you find CMBS, notify your county Extension office. Tracking the spread helps communities prepare and respond.

When to Call an Arborist

If you notice white bumps, sooty mold, or sticky honeydew on your crepe myrtles, contact an arborist for identification and treatment planning. CMBS can spread to neighboring trees, so early treatment protects your landscape and your neighbors'. EastLake Tree Services provides targeted CMBS management as part of our plant health care services.

Atlanta-Specific Considerations

CMBS has spread aggressively throughout metro Atlanta since its arrival. The city's warm climate supports year-round scale survival (unlike colder regions where winter may reduce populations), and Atlanta's enormous crepe myrtle population provides abundant hosts. The pest spreads through wind dispersal of tiny crawler-stage nymphs, bird transfer, and movement of infested plant material.

Given the ubiquity of crepe myrtles in Atlanta landscapes—from residential yards to commercial streetscapes—CMBS management has become a standard component of tree care in the region. EastLake Tree Services stays current on the latest CMBS research and treatment protocols. Call 404-850-1174 or request a consultation.