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The boxelder bug is a common red and black insect found on boxelder trees during the summer. Usually these bugs are a nuisance only during the early spring or late fall when they congregate in large numbers on the sides of buildings and other structures and subsequently enter homes.
Adult boxelder bugs are flat, bright-colored insects with three narrow red stripes on the prothorax (area behind head). The wings are thick and leathery at the base and membranous at the tips. Nymphs, or immatures, resemble adults in shape except they are smaller, wingless, and bright red or orange. Adults are approximately 1/2 inch long and 1/3 inch wide.
Small red eggs are laid by females in crevices of tree bark and on objects near host plants in the spring. Nymphs hatch from the eggs in approximately 14 days and feed on new leaves and tender twigs of their host. Nymphs pass through five instars, or growth stages, before becoming winged adults. Adults begin to appear in midsummer.
Host(s):
Boxelder bugs are found primarily on seed bearing boxelder trees although they may occasionally feed on maple, ash, plum, cherry, and apple.
Damage/Symptoms:
With the arrival of cold weather, winged adults seek shelter to pass the winter. These bugs move to hibernation sites and congregate in large numbers on the bark of host trees, in cracks and crevices in walls, in door and window casings, around foundations and in other protected places. Eventually many bugs get into homes, offices and other buildings. On mild days during early winter and spring, overwintering bugs sometimes appear again to warm in the sun on light colored surfaces of buildings which face south and west. They do not damage buildings, food or fiber products but may occasionally bite if handled carelessly. However, the bite is not painful and the insect does not transmit a disease. Indoors, they may stain fabrics and walls when crushed. They can also produce an unpleasant odor.
Comments:
The removal of suitable host plants will reduce boxelder bug populations. However, since trees are desirable for shade and aesthetic purposes, preventing the bugs from entering the home may be more practical. All openings where boxelder bugs can enter the building should be repaired or sealed, including areas around poorly fitting doors and windows, and openings through the foundation.
Young exposed nymphs and adults on the host trees may be treated with insecticides. Insecticides should be applied to the trunk, limbs and foliage of infested trees in the spring and early summer. Areas frequented by boxelder bugs in late summer and fall can also be sprayed. Several insecticides for outdoor use are available to homeowners. Older insecticides approved for use include products such as diazinon and carbaryl (Sevin). Some newer products contain active ingredients such as cyfluthrin, deltamethrin, tralomethrin, permethrin, and others. These products can be applied directly to the insects where they congregate on walls, tree trunks, fences, sidewalks, porches, etc. Some formulations of carbaryl should be applied with caution as staining of some surfaces may occur. Diazinon for residential uses will be phased out of the marketplace by December 2004. Careful adherence to the insecticide label should always precede any application; always read and follow the label directions. Treatments may be repeated if infestations persist.
Indoor control is difficult due to the scattered infestation of boxelder bugs throughout the house. Household contact aerosol sprays containing pyrethrum, permethrin, resmethrin and others may provide temporary control. When infestations affect large areas or occur in areas requiring specialized spray equipment, a professional pest control operator may be needed.
