Crape myrtle bark scale is a serious pest of crape myrtle, or crepe myrtle, trees. As the pests feed on new growth, tree branches begin to die. Flowering is reduced and, if left unchecked, an infestation will eventually kill the tree. Multiple generations can occur in a single growing season with populations, and the resulting damage, continuing to increase.
Crape Myrtle Species and Cultivars
There are many species and cultivars of crepe myrtle (Lagerstoemia spp). These are popular trees in USDA hardiness zones 6-9 because they tolerate hot weather and a variety of soil conditions. Of course, the real draw is their showy, long-lasting flowers. Dwarf varieties like ‘Pocomoke‘ and ‘Enduring Summer’ are good for small spaces and even containers. Though these only grow to about 3-4 feet, other options are available in nearly any height up to 25 feet. Choices such as ‘Catawba,’ ‘Tuscarora,’ ‘Dynamite’ are popular mid-size trees. Beyond their beautiful flowers, most crape myrtles also have shedding bark with interesting and beautiful patterns that stand out in a winter landscape. You’ll notice these trees as screens and privacy borders as well as specimens in a landscape.
Signs of Crape Myrtle Bark Scale
When these pests feed on plant tissue, they produce a substance called honeydew. This residue makes a sticky mess on the tree itself as well as nearby surfaces, and is often the first sign of infestation. Soon after honeydew often comes sooty mold fungus. The fungus grows on plant surfaces where honeydew has accumulated. Like its name implies, sooty mold fungus appears as a black coating on leaves and twigs. Though honeydew and sooty mold are associated with crape myrtle bark scale, infestation by other pests like aphids can result in the same symptoms. Proper identification of the underlying issue is key to ensuring treatments are effective.
When crepe myrtle bark scale is present, the pest itself can also be visible. They are small, fuzzy, white insects. When populations are low, the insects may look like little, white dots on the tree. In a heavy infestation, pests can mostly cover entire branches.
Management and Treatment Options
Timely management can help mitigate the development of severe symptoms. Topical treatments have proven very effective. Further, many natural enemies feed on this pest including biological control species. As part of an integrated pest management program, some predatory species, including certain lady beetles and green lacewings, can be released to supplement the natural enemies already present in the landscape for better control.
