Boxelder Bug

Pest Identification & Damage

Adult Boxelder Bug

Common Name(s):

Boxelder Bug, Democrat Bug

Scientific Name:

Boisea (=Leptocoris trivittata (Say), Hemiptera: Family Lygaeidae.

Another species, the western boxelder bug, B. rubrolineata Barber occurs in CA and OR. Both attack pistillate (female, seed-producing), but not staminate (male) trees of ash, maple and boxelder.

Identifying Characteristics for Damaging Stage(s):

Adult bugs are about 1/2 inch long, dark brownish grey to black with red markings, with three bright red lines running lengthwise on the thorax and reddish veins on the wings. Boxelder bugs are flattened insects, and the forewings overlap on the back. The immature bugs are referred to as nymphs and are wingless, solid red in the earlier stages, but later stages have black markings. The skin is shed a total of five times during the developmental period.

Damage/Nature and Symptoms:

The boxelder bug is a sap-sucking insect with piercing-sucking mouthparts. Normally the insects cause little or no damage to host trees or to plants in homes, which they often enter. While the bugs can and do bite people, this is very unusual. Rarely the insect may kill twigs or leaves of boxelder and ash trees and they can occasionally cause deformed fruit (apples, cherry, strawberry, pear, peach, plum, grape).

In homes, the insects are common nuisance pests which can sometimes stain draperies, clothes, furniture, or paper with fecal spots.

Distribution and Life Cycle

Distribution:

This common insect is generally distributed throughout most urban and rural areas of the eastern U.S. and westward to Nevada.

Summary of Life Cycle:

Adult bugs winter as adults in protected places, often in home attics and wall voids, other protected places, hollow trees, barns and outbuildings, leaf piles and walls. The insects often emerge to sun themselves on warm, light-colored vertical surfaces during the winter months. In the spring, the insects move to their preferred hosts, female boxelder, maple and sometimes ash trees. The insects prefer to feed pistillate trees, and on dropped seeds which often collect in windrows adjacent to home foundations. Thousands of nymphs, which may develop from reddish eggs laid in cracks and crevices in bark, can feed on leaves, stems and tender twigs as well. Eggs laid in spring hatch two weeks after laying, and a second batch is produced in late summer, resulting in two generations per year in the southern U.S. and one in north. Adults fly to south sides of homes in autumn, persisting outdoors until weather cools, then entering home foundation and exterior walls through cracks and crevices.

Management Methods:

Inspection/Survey Methods:

Periodically examine maple, boxelder and ash trees and seeds accumulated along foundations for the presence of nymphs and adults.

Non-Chemical Management Strategies:

The best control strategy is one of prevention -- avoid planting BE bug susceptible trees such as boxelder, maple and ash. Otherwise, plant male trees (staminate) that are propagated from cuttings. Pick up and dispose of seeds that accumulate around home foundations. Seal and caulk around windows, chimneys, and door frames. Use pyrethrins or a simple fly swatter inside homes to kill bugs or a vacuum cleaner to remove them.

Chemical Management Strategies:

Chemical management is not often practical to control this nuisance pest, particularly on host trees. Sprays may be used, however, to treat vertical exterior walls, foundations, around doors and windows, shrubbery, accumulated seeds on the soil surface, mulches around the foundation and soil.

For the latest information on available chemical controls, consult the Pesticide Selection Guide.

References:

Baker, W. L., 1972. Eastern Forest Insects. USDA Forest Service Misc. Pub. No. 1175, US Forest Service, 642 pp.

Metcalf, C. L., W. P. Flint and R. L. Metcalf, 1962. Destructive and Useful Insects. 4th Ed. McGraw-Hill Book Co., New York NY. 1087 p.

White, Stephan C. and Glenn A. Salsbury, 2000. Insects in Kansas. Kansas Department of Agriculture, Topeka KS. 521 pp.