Crape Myrtle Bark Scale Insect

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Crape Myrtle Bark Scale Insect

Common Name

Crape Myrtle Bark Scale; CMBS

Scientific Name

Acanthococcus lagerstroemia

Host Plants

Crape Myrtle (preferred)
American Beauty berry
Kalm's St. John's Wort
Apple
Fig
Persimmon
Pomegranate

Figure 1: Jill Pollock, Diagnostician, University of Delaware

(Figure 2) Photo Credit: Tracy Wootten, CEA, University of Delaware

(Figure 3) Photo Credit: Jill Pollock, Diagnostician, University of Delaware

Signs

White, wooly adults (figure 1, 2) with pink to purple eggs underneath (Figure 3) can be seen in late spring.

The first generation was observed in late May through early June using a hand lens or viewing double-sided tape under a dissecting scope at 631 - 803 GDD and a 2nd in early August around 2,233 - 2357 GDD (Figure 4).

Symptoms

Honeydew, a sugary excrement, can be seen on bark and leaves

Sooty mold can follow honeydew and turn bark and leaves black and gray (Figure 2). It is not a pathogen but will discolor plants

Crape myrtle has reduced flower size and vigor under CMBS pressure compared to healthy crape myrtle

(Figure 4) Photo Credit: Jill Pollock, Diagnostician, University of Delaware

Management

When crawlers are active, contact insecticides and growth regulators are effective.

Soil-drench systemic insecticides are also effective. Applications should be applied early, generally mid-April.

For specific recommendations and questions regarding application timing, contact your local cooperative extension office.

Biology and Life Cycle

Crape myrtle bark scale begins its life cycle as tiny, pink to purple colored crawlers (<mm), which subsequently produce a fuzzy white waxy cover. Females remain sessile under the cover, whereas males pupate and leave their covers as a tiny, pink, gnat-like insect with wings (Figure 5) to mate before dying. Females oviposit 100-300 eggs underneath their waxy cover before dying. The first generation of eggs hatch from late May to early July (between 631-803 GDD in Georgetown, Delaware). We are studying this pest to determine how many generations there are and how it overwinters in the Mid-Atlantic.

(Figure 5) Seen in: Crapemyrtle Bark Scale: A New Threat for Crapemyrtles, a Popular Landscape Plant in the U.S. Wang and Díaz et al, Louisiana State University

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