Scale insects can vary in color, size, host plant preference, and life cycle. Scale infestations commonly go undetected until there is a large population present. Scale insects are divided into two groups, soft scales and armored scales. Soft scale are sap-sucking insects and emit honeydew, similar to aphids. Therefore, black sooty mold is often coating the bark, leaves, and area beneath plants with scale infestations as the honeydew supports the growth of sooty mold. Armored scale do not produce honeydew.

Most scale are immobile for much of their lives. Newly hatched scale are referred to as crawlers as they crawl around actively feeding. Scale are more susceptible to contact insecticides in the crawler stage as they have yet to form a protective cover. Once the protective cover is produced, they continue to feed under their protective outer cover in one place on the plant. Older life stages are best controlled with systemic insecticide treatments.

The application of a dormant oil spray during late winter or early spring before bud break can aid in control. Remove heavily infested branches. The crawler stage is the easiest stage to control. Begin treatments using one of the recommended insecticides in late April or as soon as crawlers are seen on the new foliage.

For chemical control recommendations, consult the Insect and Plant Disease Control Manual, UT Extension Publication 1690, found here. Please contact your local Extension office for specific pesticide recommendations.