Crape Myrtle Scale Infestation: Honeydew, Ants, and Systemic Control

Diagnosing the Infestation

10-year-old crape myrtle with attached insects on branches/trunk, sidewalk sap (honeydew), and ladybug-like black/red beetles has scale insects—the beetles are ladybugs (predators) eating scales. Scales suck sap, excrete honeydew → sooty mold → black sidewalk stain.

Comprehensive Control Options

Foliar sprays (crawler-targeted):

• Monitor from late April & mid-August for white "star-like" settled crawlers.
• Spray 7–10 day intervals with insecticidal soap, horticultural oil, or acephate (Orthene).

Soil-applied systemic (preferred for large trees):

• Imidacloprid (Merit, Bayer Advanced) applied pre-hatch.
• Moves to leaves/trunk via sap; kills feeding scales.
• Dead scales persist but eventually fall.

Local Action

Buy systemic scale product at nursery; follow label precisely. Systemic is most practical for 10-ft+ trees.