How do You Identify Bark Scale on Crape Myrtles?

Identifying crape myrtle bark scale (CMBS) involves looking for specific physical markers and secretions on the tree’s woody tissue. According to Miller Tree Service and the LSU AgCenter, you can identify an infestation by following these steps:

• Check for White Waxy Crusts: The most distinctive sign is the presence of white, waxy secretions or crusts clinging to the branches and trunks. This residue consists of clusters of adult female scales and their egg masses.
• Perform the Crush Test: To distinguish CMBS from harmless lichen, crush the white crust. If it produces a pinkish or reddish fluid, it confirms the presence of living scale insects.
• Examine for Black Sooty Mold: Look for a dark, sticky fungus coating the leaves and bark. This mold grows on honeydew, a sugary residue excreted by the insects. While many property owners notice the mold first, it is a secondary symptom of the scale infestation.
• Observe Insect Activity: The presence of ants and wasps can be a visual cue, as these insects are attracted to and feed on the sugary honeydew secretions.
• Differentiate from Mildew: Unlike powdery mildew, which appears as a white dusting on leaves, bark scale specifically targets the woody tissue (branches and trunks) of the tree.

Early identification is critical to preventing symptoms like twig dieback, stunted blooming, and reduced tree vitality.

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