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Be on the Lookout for Crapemyrtle Bark Scale!

Be on the Lookout for Crapemyrtle Bark Scale!

Figure 1 Note the black sooty mold coating the layers of white and grey scale, believed to be crapemyrtle bark scale, Eriococcus lagerstroemiae. [Photo by Gary Knox]

Figure 1 Note the black sooty mold coating the layers of white and grey scale, believed to be crapemyrtle bark scale, Eriococcus lagerstroemiae. [Photo by Gary Knox]

Crapemyrtle bark scale, Eriococcus laqerstroemia, is a new pest of crapemyrtle and is emerging as a major threat to crapemyrtles throughout Florida and the Southeast U.S.  This pest was first discovered in the Dallas TX area in 2004 and in recent years has spread rapidly to areas such as Tulsa OK, Memphis TN, New Orleans and Shreveport LA and Mobile AL (very close to Florida). The expanding distribution of crapemyrtle bark scale and my personal observations of this pest on crapemyrtle in China suggest it could have a widespread and severe impact on crapemyrtle production, use and marketability. For more updated information on where this pest has been found, go to http://www.eddmaps.org/cmbs/distribution.cfm.

 

Symptoms and Appearance

An early symptom of crapemyrtle bark scale is black sooty mold covering extensive areas of leaves and stems as a result of honeydew exuded by the scale (Fig. 1). Individual scale insects are white to gray in color and ooze pink when crushed (Fig. 2). Large populations build up in branch crotches and extend up branches, appearing crusty white to gray. This scale usually is not present on new growth, leaves or slender stems unless infestations are heavy.

 

For more information and additional photos

Resources, up-to-date information and additional photos about crapemyrtle bark scale may be found at http://www.eddmaps.org/cmbs/. This website will be the major portal for information about this pest.

Figure 2. This white to grey colored scale oozes pink when crushed. [Photo by Gary Knox]

Figure 2. This white to grey colored scale oozes pink when crushed. [Photo by Gary Knox]

Research

Research on crapemyrtle bark scale is ongoing. Scientists from the University of Florida, LSU, University of Arkansas and Texas A&M are collaborating to develop Best Management Practices to manage crapemyrtle bark scale in the nursery and landscape.  Initial research is examining the biology of the host-insect interaction to better understand its life cycle and stages when it may be most susceptible for control. Additional research will evaluate pesticides and other IPM strategies for managing this pest.

 

The expanding distribution of this scale and my personal observations of crapemyrtle bark scale throughout China suggest this scale could have a widespread and severe impact on crapemyrtles in landscapes. Please be on the lookout for crapemyrtle bark scale, and report sightings to your local county extension agent and Florida Department of Agriculture and Consumer Services Division of Plant Industry.

 

 

PG

Author: Gary Knox – gwknox@ufl.edu

Gary Knox is an Extension Specialist and Professor of Environmental Horticulture with the University of Florida at the North Florida Research and Education Center in Quincy. Dr. Knox’s research interests focus on evaluating species and cultivars of woody plants for their invasive potential as well as for ornamental characteristics. In addition to research plantings, Dr. Knox is working with a nonprofit volunteer group to develop “Gardens of the Big Bend,” a series of botanical, teaching and evaluation gardens at the Center.

Gardening in the Panhandle

Permanent link to this article: http://liberty.ifas.ufl.edu/newsletters/2015/03/31/be-on-the-lookout-for-crapemyrtle-bark-scale/