Recommendation for treating Crape Myrtle Bark Scale - Ask Extension
My Crape Myrtle trees have serious bark scale. What are you recommending for professional treathment?
Knowledgebase
Recommendation for treating Crape Myrtle Bark Scale #925354
Asked March 03, 2026, 12:44 PM EST
My Crape Myrtle trees have serious bark scale. What are you recommending for professional treathment?
Montgomery County Maryland
Expert Response
Crapemyrtle Bark Scale management, if insecticides are used, generally involves either systemic treatments or topical horticultural oil sprays. (Potentially IGRs, insect growth regulators, as another option alone or in combination with hort. oil.) You can find management options mentioned in our scale management page section online (see link).
Since this scale species produces multiple (at least 2, almost 3) overlapping generations per year in central Maryland, control using carefully-time smothering hort. oil sprays can be challenging, as such treatments need to target crawlers (the "hatchling" stage) to be most effective. Systemic options, which are absorbed by the plant and ingested by the scale, make the timing less critical, but their use is limited to certified pesticide applicators as per Maryland law (at least for the most widely-used category of systemics, neonicotinoids ingredients like imidacloprid and dinotefuran). Even effective systemic treatments might take a year or more to achieve good control of a well-established or high population of scale.
Systemic insecticides bear the greatest risk to pollinators and other beneficial insects or wildlife, so their use should be a last resort. We've found that, in some cases, even high populations of Crapemyrtle Bark Scale are reduced effectively by naturally-occurring populations of predators like certain species of ladybug, whose larvae look nearly identical to the scale as they roam about the plant eating them.
Miri
Since this scale species produces multiple (at least 2, almost 3) overlapping generations per year in central Maryland, control using carefully-time smothering hort. oil sprays can be challenging, as such treatments need to target crawlers (the "hatchling" stage) to be most effective. Systemic options, which are absorbed by the plant and ingested by the scale, make the timing less critical, but their use is limited to certified pesticide applicators as per Maryland law (at least for the most widely-used category of systemics, neonicotinoids ingredients like imidacloprid and dinotefuran). Even effective systemic treatments might take a year or more to achieve good control of a well-established or high population of scale.
Systemic insecticides bear the greatest risk to pollinators and other beneficial insects or wildlife, so their use should be a last resort. We've found that, in some cases, even high populations of Crapemyrtle Bark Scale are reduced effectively by naturally-occurring populations of predators like certain species of ladybug, whose larvae look nearly identical to the scale as they roam about the plant eating them.
Miri
