Those pesky boxelder bugs are coming to a home near you. Randy Meier spotted a large gathering of the black and orange bugs on his trees, as seen in the video above.
In Minnesota, boxelder bugs emerge during the spring warmup to feed on the ground and start mating. By mid-summer, the bugs move to boxelder, maple and ash trees to lay their eggs on trunks, branches and leaves. During late summer and early fall, boxelder bugs leave the trees to find protection from the cold of winter.
Some homes are especially attractive to boxelder bugs, usually depending on the amount of sun exposure. Boxelder bugs like warm areas and are typically attracted to buildings with a large southern or western exposure.
As cool autumn air moves in, boxelder bugs push into the cracks and spaces around homes, and can often be found around the windows of homes and apartments. Boxelder bugs do not bite people and don’t cause significant property damage, but they can stain walls, furniture and other surfaces with their yellowish excrement.
The best management of boxelder bugs is prevention. If you don't want them in your home, seal any cracks or openings before the end of August.For all homes
Repair or replace damaged window and door screens.
Repair or replace damaged screens in roof and soffit vents, and in bathroom and kitchen fans.
Seal areas where cable TV wires, phone lines, and other utility wires and pipes, outdoor facets, dryer vents and similar objects enter buildings.
Seal with caulk or for larger spaces use polyurethane expandable spray foam, copper mesh, or other appropriate sealant.
Install door sweeps or thresholds to all exterior entry doors. Install a rubber seal along the bottom of garage doors.
For homes constructed of stucco, plaster, stone or brick veneer
Check the outside surfaces for spaces and cracks that may allow insects easy entry, sealing any openings 1/8th inch in size or larger. This will not eliminate all boxelder bugs but it can significantly reduce the number entering buildings.
Seal cracks and spaces around doors, windows, roof lines, and fascia boards and other areas where vertical surfaces meet horizontal ones.
Also check for gaps and cracks where different materials meet, such as brick and wood siding. Seal cracks with caulk, such as silicone, elastomeric latex, or silicone/acrylic.
For stone or brick veneer, the bottom of the walls will have ‘weep holes’ and these must not be sealed up. Instead, visit a local hardware store and request ventilation plugs that can be installed in these weep holes.
For homes constructed of vinyl siding
Unfortunately, houses with vinyl siding provide too many gaps to effectively exclude these insects. These houses are designed for aesthetics, durability, and energy efficiency. Relative to excluding insects, the benefit of these houses is that they are often effectively sealed with a ‘house wrap’ placed underneath the siding.
For these types of houses, concentrate on the recommendations provided for all houses and use an insecticide on areas where these bugs have congregated in the past. In our experience, large numbers collecting around the doors and other entryways are often the most prevalent means of entry during the fall.
Once boxelder bugs are found the best option is to physically remove them with a vacuum or a broom and dust pan. If this occurs during fall, check around the building exterior because they can often be found congregating in sunny or warm areas. If they are close to entrances, an insecticide may be required to prevent their entrance into a home.
Inside homes, insecticides have limited value and are not usually suggested. Remember that when boxelder bugs are active, they do not live indoors much more than a few days and do not reproduce inside. When they are emerging from the walls and other sites where they have been dormant during the winter, spraying insecticides does not prevent more from returning.