Scale insects, found on stems, small branches, or the undersides of leaves bear little resemblance to typical insects. They appear as brownish crusty bumps; white, waxy bumps; or clusters of flat, scaly bumps. These bumps enclose the insects which are sucking sap from the plant.

Soft-bodied scales produce honeydew that may lead to a black sooty mold fungus, making the leaves appear black, and/or may attract ants. An uncontrolled infestation may kill the plant after several seasons.
SCALE INSECTS CONTROL OPTIONS
There are usually several management options for solving any pest or disease problem. Use the non-pesticide approach whenever possible, saving pesticide use as the last line of defense. If a pest is identified at a damaging level, select a control targeted to the problem. This is called “Integrated Pest Management ”or “IPM ”.

LIFE CYCLE AND TIMING OF CONTROLS
Adult scales lay eggs under their protective covering. The insects that hatch (called crawlers) have legs and are very mobile. The crawlers move about the plant and find a new area to feed. The protective covering is then formed and the mouthpart is inserted into the plant tissue.

Over 20 types of scale insects are found in SE Michigan - each with its own time of emergence of crawlers.

Hotline for specific recommendations:248/858-0902.

MECHANICAL REMOVAL
Remove adult scales from twigs, branches and leaves using a soft cloth containing insecticidal soap. Rinse well to prevent burning leaves. Scraping scales off with your fingernails is fine if you can avoid injuring the plant.

HORTICULTURAL OILS
Apply horticultural oils in late winter/early spring to control over-wintering eggs that are under the protective bumps. Highly refined oils can be applied when crawlers are present. Since timing is critical for effective control, contact the MSU Extension-Oakland County Garden Hotline for recommendations: 248/858-0902. Then follow label instructions.

CHEMICAL CONTROLS
If you have decided to use a chemical insecticide, read the precautionary statements on the label before making your selection.

READ THE LABEL BEFORE BUYING ANY PESTICIDE.
Re-read the label before using, storing or disposing of the pesticide - the label is the law. Following label instructions will help reduce risks to human health and the environment.
Sources of information:
Greg Patchan, Horticulture Agent, Oakland County MSU Extension.

Ellis and Bradley, Natural Insect and Disease Control, Rodale Press

Ellis Taylor ’s Weekend Gardening Guides:

Organic Pest & Disease Control, Houghton Mifflin

FOR ADDITIONAL INFORMATION:
Oakland County Garden Hotline:248/858-0902

National Pesticide Telecommunications Network (NPTN):1-800-858-7378
(Information about environmental and health effects of specific chemicals)

Household pesticide disposal: If you live in one of the SOCRRA communities, call for an appointment:248/288-5153
Download PDF of this Tip Sheet