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September/october 1999

Insects that Overwinter in Our Homes
by Rose Hiskes

Fall is the time to seal your home against some of the nuisance insects that will be looking for warm winter quarters. For the most part, these insects are preparing for cold weather just like you are. They find small openings into your home and don't wait for an invitation.

The multicolored Asian ladybeetle, Western conifer seedbug and boxelder bug can all be problems in Connecticut homes. Multicolored Asian ladybeetles and boxelder bugs release an aggregation pheromone, or chemical message that says "Come together," prior to hibernation. They can be a bigger problem because they come in and bring a thousand friends with them.

The multicolored Asian ladybeetle occurs in many shades of orange and red, with or without black spots. The convex adults are around 1/4 inch long and 3/16 inches wide. The 3/4 inch long Western conifer seedbug is a dull brown true bug with small white markings on its back. Antennae have a dark base and top, while the hind legs have an enlarged flattened area that is leaf-like. Also a true bug, the boxelder bug is smaller, 1/2 inch long, black with small red areas along the margins of the wings.

The above bugs, though nuisances, do no real damage to your home or person. They are simply seeking a place to hibernate for the winter. They will not eat your food or reproduce. Handling the multicolored Asian ladybeetle or the Western conifer seed bug may cause them to give off a defensive chemical that may smell bad and stain fabrics or painted surfaces.

Outdoors, the multicolored Asian ladybeetle is very beneficial, eating many softbodied pest insects, including the hemlock woolly adelgid. The Western conifer seedbug eats the seeds of many pines, spruces and hemlock. The boxelder bug eats the seeds of the boxelder tree, a type of maple.

Control
If any of these bugs are a problem in your area, prevention is the best strategy. Carefully look over the exterior of your home. Caulk any cracks around windows, doors and utility pipes. Foam insulation strips will seal triple track storm windows. Where possible, screen vents, fireplaces and chimneys.

There are no pesticides registered for use against these pests in houses. The ladybeetle is beneficial so gently sweeping them into a dustpan and putting them outside will benefit you next summer. Remove large numbers of bugs with a dustbuster or large vacuum using on of the attachments. Using the beater bar or power head on a vacuum will kill insects. Leaving the vacuum outside for a time will allow the bugs to "escape" and find a winter home in your yard.

Western conifer seedbugs don't aggregate so they frequently occur in lower numbers that are easily removed by hand. There is a fly that parasitizes adult Western conifer seedbugs. Make sure you conserve this natural enemy by not killing any of the Western conifer seedbugs that have the white eggs of the parasite attached to their head.

The boxelder bug is less common than the previous bugs. Removing any of the host trees of these bugs that are near your home may also cut down on the number of pests entering your home, but is usually too drastic a step to take for most landscapes.

As the weather warms in the spring these insects will again begin moving about. Open your windows and let them go.

Rose Hiskes is a Research Assistant at The Connecticut Agricultural Experiment Station.

Connecticut Gardener
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