Many years, right around Halloween people are invaded by bugs that look like they are dressed for the season. Strikingly marked black and orange or black and red insect about 1/2” - 1/3” long. These may be boxelder bugs.

Boxelder bugs are true bugs, belonging to the order hemiptera. All bugs are insects, but not all insects are bugs. Boxelder bugs have piercing-sucking mouthparts and feed buy sucking the juice out of their host plants. According to some authors, boxelder bugs can feed on a wide variety of plants, but we see them feeding most often on the seeds and young shoots of boxelder and certain maple trees. Occasionally they damage trees and plantings. Their eggs are laid either under leaf litter or in cracks in the tree bark.

The nymphs that hatch from these eggs are wingless and bright red. There are usually 5 nymphal instars, the last on having dark patches where the adult wings will appear. Boxelder nymphs occasionally appear in such numbers that it appears as if the ground or tree has been painted red. All through the spring and summer the bugs will remain on the trees and can often be seen flying from seed cluster to seed cluster in the manner of honey bees visiting flower blossoms. Problems start either when the weather turns colder or the tree begins to drop its leaves and the seeds. The adult bugs will seek places to spend the winter. They are attracted to bright colored surfaces, and at times the sunny sides of houses will be literally covered with them. Some invariably find their way in.

Control at this stage is very difficult and consists of removing the individual insects inside, possibly with the help of a vacuum cleaner to avoid stains caused by crushing them. Outdoors chemical control will probably be called for. Ideally trees should be sprayed while the insects are feeding actively; towards the end of the summer. If this opportunity is missed, spraying the wide of the house will result in some control. One word of caution: boxelder bugs are strong fliers and may arrive at your house from an infested tree more than a mile away. Boxelder bug populations appear to be cyclical. They are extremely abundant in some years, and very rare other years.