Armored Scales

Scale insects are divided into two groups, armored scales and soft scales, and if you need to control a scale problem, it helps to know which type of scale you are trying to control. The most important distinction is that armored scales do not produce honeydew, while soft scales produce large amounts of honeydew. Armored scales also tend to be smaller than soft scales and have more generations per year. As the group names suggest, armored scales also have a harder, more scale-like covering than soft scales. Some of the most common species of armored scale include: tea scale, which is common on camellias and hollies; false oleander scale, which occurs more in the southern part of the state on leaves of magnolia and oleander; and euonymus scale, which is a serious pest of euonymus, especially evergreen species (E. japonicas and E. fortunei). Because they are mobile and do not have covers, newly hatched scales, known as crawlers, are relatively more susceptible to contact insecticides. Older life stages are best controlled with systemic insecticides, but some systemic insecticides work better than others against armored scales.

Control Armored Scale: When attempting to control heavy armored scale infestations it is usually best to use a combination of treatment methods. Begin by pruning plants to remove dead or dying branches or heavily infested limbs and to remove suckers and other excessive growth. Soil-applied systemic treatments of products that contain dinotefuran (Greenlight Tree & Shrub Insect Control) are especially useful against most armored scales. This treatment is slow-acting, but can provide long-term control. Rate depends on the size of the tree or shrub being treated; sprinkle the specified amount of granules on the soil immediately around the plant and water in according to label directions. Sprays of contact insecticides, such as malathion or acephate (Bonide Systemic Insect Control), applied when crawlers are active, are also effective. Sprays of horticultural oil (such as Volck oil or Bonide All Seasons Horticultural & Dormant Spray Oil) are also especially useful against many armored scales, especially when applied a dormant sprays in late fall/early winter, or as delayed dormant sprays in early spring. Follow label directions carefully. In some cases, such as a planting of euonymus that suffers heavy, recurring infestations, replacing heavily infested plants with less scale-prone species may be the best long-term solution.

See Insect Pests of ornamental plants in the home landscape, pages 7-10 and pages 35-36 for more information on armored scale insects. See page 8 of this publication for information on how to determine when scale crawlers are active.

Printer Friendly and PDF

Publications

Publication Number: P2472
Publication Number: P2652

News

Crape myrtle bark scale were found in Mississippi in March. This invasive insect, photographed in Ocean Springs, Mississippi, on March 15, 2015, attacks beautiful and normally low-maintenance crape myrtles. (Photo by MSU Extension Service/Gary Bachman)
Filed Under: Lawn and Garden, Insects-Ornamental Plants, Insects-Pests, Landscape Architecture, Trees April 2, 2015

OCEAN SPRINGS, Miss. -- A new insect pest found in Mississippi on March 15 could take away the crape myrtle’s status as a beautiful and low-maintenance landscape tree.

Crape myrtle bark scale, or CMBS, is an invasive insect that came to the United States from China. It was first found in Texas in 2004 and has since spread east to Shreveport and Houma, Louisiana; Little Rock, Arkansas; and Germantown, Tennessee. Ocean Springs joined this list when the insect was found on the coast in Jackson County.

Contact Your County Office

Your Extension Experts

Extension Professor
Entomology; extension insect identification; fire ants; termites; insect pests in the home, lawn and