by Wayne Ohnesorg

How do I keep box elder bugs from invading our farm home? The eastern boxelder bug (Boisea trivitattus) can be a source of consternation for many people.

Its habit of finding a way indoors seems to be one of the main reasons for the angst. The most common times for people to encounter large numbers are in the fall and spring. However, warm, sunny days in winter will get boxelder bugs stirring.

They will congregate on the south or west sides of buildings, where there is exposure to sun during spring and fall. This can lead to an invasion of the structure when the bugs move into it to escape the cold temperatures of winter. Now, don’t begrudge them as they are only trying to survive the winter and complete their life cycle.

To complete the life cycle, the boxelder bugs that survive the winter will emerge on warm spring days. They will feed on seeds they can find on the ground from last year. Despite their name, boxelder bugs will feed readily on the seeds from maples, ash and boxelder.

About two or three weeks after they start feeding, they will start to mate. They then move to trees, from those already mentioned, that bear seeds. It is in these trees that they will feed on seeds during the summer. So, in other words, male ash and boxelder trees are just about worthless to boxelder bugs. Eggs are laid on the trunks, branches and leaves of those trees.

Then in the fall, bugs will congregate again on the sides of structures with south and west exposures. There will be a mixture of adults and some nymphs in these aggregations, but only the fully grown boxelder bugs can survive through the winter.

There are a number of things one can do to reduce the population of boxelder bugs in the landscape. Tree selection can play a big role. Species other than maples and ashes, or the male trees of those species, will help to reduce the available summer habitat. This does not always work well when suitable trees occur in neighboring areas.

Insecticides may be used per label directions to keep boxelder bugs from entering structures. A foundation spray may be applied to the aggregation sites on structures. Another method would be to apply the insecticide directly to the aggregations of the bugs. In both cases, repeat applications may be needed.

However, you could always just enjoy the intricate design of nature and the behaviors of its creatures.

Just a reminder that when you are using any pesticide, be sure to read and comply with all label directions.

Ohnesorg is a Nebraska Extension educator.

Please email your farmstead landscaping, turf, forestry or gardening questions to [email protected].