![]() ![]() They are most effectively applied in spring as new plant growth begins. These systemic insecticides will move up into the plants and give control for at least a year. This systemic insecticide is available in a number of brands as concentrates for use as a soil drench, and in a few brands as granular products to scatter around the plants and water into the soil. If alive, scraping will result in “bleeding” of their reddish body fluids.Ĭhemical Control: The most effective chemical control is a soil drench in the spring with dinotefuran. Scraping the soft crapemyrtle bark scales can reveal if the scales are alive or dead. Natural predators may take a while to build up in numbers, but both lady beetles and mealybug destroyers are very effective in controlling CMBS. These plants should be closely inspected for the CMBS, especially if crapemyrtles are planted nearby. These include pomegranate, persimmon, edible fig, boxwood, American beautyberry, cleyera, privet, and raspberries. Several other common landscape plants are susceptible to CMBS infestation. So, always plant crapemyrtles in the full sun areas of the landscape. Crapemyrtles in sunnier sites often have smaller infestations than plants growing in more shade, and plants grown in shade typically have more crawlers (immatures) than in full sun. Please see HGIC 1009, Crapemyrtle Pruning for best pruning practices. ManagementĬultural Control: Keep crapemyrtles healthy by properly mulching, irrigating, fertilizing (based on soil test recommendations), and proper pruning. Often there will be more female adults congregated on the lower (and shadier) sides of branches. ![]() With a scale heavy infestation, there may be premature bark peeling. Aphids are small insect pests that feed on new tender growth on the ends of branches. However, do not confuse the honeydew and resulting black sooty mold caused by an aphid infestation with that caused by the crapemyrtle bark scale. Another striking symptom is the extensive amount of black sooty mold that may completely cover the foliage, branches, and trunks. Branches and trunks can be covered in the white scale infestation. ![]() Infested plants typically leaf out later than healthy plants. These bark scales may not kill the plants, but there may likely be a reduction in plant vigor, number of flowers, and flower cluster size. Jim Robbins, University of Arkansas CES, Ĭrapemyrtles suffer aesthetic damage because of the CMBS infestations. A closer inspection of infested crapemyrtles will show copious sooty mold on leaves, branches, and trunks. The tree on the right is infested and shows reduced flowering. The crapemyrtle on the left was treated to control crapemyrtle bark scale. These mobile crawlers move out to new twigs and branches to settle down and begin feeding on the sugary phloem layer beneath the bark. Double-sided sticky tape wrapped around small branches can be used to trap the crawlers to see when they hatch and to base the timing of additional contact insecticide applications. A second peak in crawler activity occurs in late summer. The crawlers are pink, very small, and may not be noticed without a hand lens. Each female lays about 60 to 250 eggs, which may over-winter within their ovisacs, and then hatch during mid- to late April to May. The eggs remain protected within the white colored ovisacs until the crawlers (immatures) hatch and disperse onto the branches. Once the mated females produce their ovisacs (egg-containing capsules) and lay eggs, they die. The small CMBS males are winged and will fly to find females and to mate. As a result, the leaves, branches, and trunk become covered with black sooty mold, which grows on the honeydew. These bark scales produce copious amounts of honeydew, the sugary waste the scale produces as it feeds on the plant’s phloem. This scale will settle to feed under loose, exfoliating bark of the crapemyrtle, which makes control by both predators and pesticides more difficult. They especially congregate in branch crotches and at pruning sites. The CMBS infestations appear as white or gray, waxy crustations on stems, large twigs, and trunks, but rarely on foliage. Bark scales are in a different scale insect family (Eriococcidae) than soft scales (Coccidae), and they look very similar to mealybugs. However, they have a waxy coating and exude honeydew, as do soft scales. The CMBS is a bark or felt scale, which is slightly different from soft scales. Mengmeng Gu, Texas A&M AgriLife Extension Service, The spent crapemyrtle flower clusters may also be covered with crapemyrtle bark scale and sooty mold. ![]()
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