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Current Research at Bartlett Tree Research Laboratories: Crapemyrtle Bark Scale Trial
Sean Henry
Research Arborist, Bartlett Tree Research Laboratories
The invasive crapemyrtle bark scale (CMBS), Acanthococcus lagerstroemiae, has become a major landscape pest deteriorating the aesthetic value of crapemyrtles across the southeastern US. The conventional treatment for this pest is a soil drench using a neonicotinoid product, however with restrictions on this class of products and client concerns due to potential pollinator issues, the Bartlett Tree Laboratories decided to trial some biological control methods using predatory insects.
This trial, designed by Dr. Kevin Chase and Ms. Amber Stiller, uses scale destroyer beetle (Rhyzobius lophanthae) and green lacewing (Chrysoperla rufilabris) against established populations of CMBS. The plants being used in this trial are the species L. indica x fauriei ‘Natchez’.
To determine if these predators reduce CMBS densities, a standardized number of either scale destroyer beetle, green lacewing, a combination of both, and neither (control) are released onto crapemyrtles infested with CMBS. These four treatments are then broken down further by either covering the plants in a net or without a net for a total of eight treatments. The purpose of the net is to exclude random predators as well as containing the released predators in the study. These treatments are replicated 12 times for a total of 96 plants in the study. Weekly checks are performed to determine scale density and predator retention throughout the duration of the trial.
When the trial period ends, the initial and final densities of scale will then be compared across the treatments and controls, to determine what degree of effect these predators have in reducing CMBS populations.
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