By Ed Lentz

We will see a change in the weather this week. With the drop in temperatures, some outdoor insects will be searching for warm areas to get through the winter.

Their movement is often noted after the first period of extended low temperatures in the 30s or after a fall warmup followed by cold weather.

Once a home has been targeted as desirable, large numbers of these insects may try to move in at one time.

These insects will not harm or damage the home, but their annoyance factor is certainly high enough to warrant control. Homes that are near crop fields are the most vulnerable, but even city residents are not immune from the invasion.

Now is the time for homeowners to block entry points to these insects. Window screens will prevent entry even if many insects gather on them. However, worn-out exterior door sweeps and open garages allow easy passage.

Insect exclusion methods include finding and sealing off entry points such as cracks and holes around windows, doors, or utility pipes.

Outside siding needs to be firmly attached, and rips in window screens should be repaired to prevent entry. All home vents need to be protected, such as bathroom and kitchen vents, or unscreened attic vents. Also, while in the attic, look for openings around soffits.

Once the bugs are inside the home, the best method to manage the offending invader is the vacuum or by picking them up by hand, and depositing them in the trash. Swatting or otherwise smashing the invader could cause more damage than leaving them alone since fluids inside their bodies can leave permanent stains on furniture, carpets, and walls.

The two most common insects that may invade homes from soybean fields are multicolored Asian lady beetles and marmorated stink bugs.

Asian lady beetle populations may be lower this year since soybean aphids, their favorite food, were not a problem in local fields. However, stink bug populations have been on the rise for the past several years.

Multicolored Asian lady beetles were introduced into the U.S. as a biological control agent for aphids and scale insects. They resemble other lady beetles (oval to dome-shaped) but are slightly larger than the native lady beetle. They may be different shades of yellow, orange or red, with or without spots.

These beetles invade homes looking for overwintering sites. Asian lady beetles can fly short distances, including within your house. They often congregate in warm spots of a home, such as corners of ceilings and walls.

Multicolored Asian lady beetles can exude a foul smelling substance that will stain fabric and material when they are threatened or crushed. They are not aggressive, but people have noted that their mandibles are large enough to cause a slight nip when handled, but it will not break the skin.

Brown marmorated stink bugs have been moving into Ohio for the past several years. They feed on a wide variety of plants with their piercing-sucking mouth parts, such as fruits and soybean plants.

Their numbers have been increasing in local soybean fields, where they can cause serious pod and bean damage.

The shield-shaped adults are about one-half inch in length and mottled brown to gray. The exposed edges of their abdomen have dark and light banding and the last two antennal segments have alternating broad light- and dark-colored bands.

Brown marmorated stink bugs have a nasty habit of entering homes and other heated structures in large numbers in the fall to overwinter. They do not bite or carry human diseases, but when threatened they will emit an unpleasant odor — thus the name stink bug.

Adults will not feed on wood or fabric or lay eggs in the home.

Other invasive insects include boxelder bugs and conifer seed bugs. They originate from trees in the area rather than farm fields.

Boxelder bugs generally reside in boxelder, silver maple, and other trees during the summer months. Adults will leave the trees in the fall and travel several miles to find the ideal overwintering site. They are attracted to taller homes or structures with a large southern or western exposure.

Boxelder bugs are about a half-inch long. They are dark colored and have a red “V” on their backs. They generally congregate in large numbers.

For the most part, boxelder bugs are polite house guests. They do not bite, and keep to themselves. However they do smell when crushed.

Western conifer seed bugs live in conifer trees and move from yard trees into homes. This bug is three-fourths inch long and brown on top. It has flattened, leaf-like rear legs. It makes a loud buzz when flying.

Adults feed on cones and seeds and the juveniles feed on needles. Adults overwinter by moving into warm shelters.

Conifer seed bugs do not damage the home. They are only looking for a warm place to get through the winter. The bugs do not bite or carry disease.

All four of these invasive insects may be found around and in homes as temperatures drop. Blocking home entry points is the best way to prevent these uninvited guests. If found in the home, they are not harmful and can be removed without using pesticides.

Additional information and images of these invaders may be found at the following website:

Lentz is extension educator for agriculture and natural resources for the Ohio State University Extension Service in Hancock County. He can be reached at 419-422-3851 or via email at

Lentz can be heard with Vaun Wickerham on weekdays at 6:35 a.m. on WFIN, at 5:43 a.m. on WKXA-FM, and at 5:28 a.m. at 106.3 The Fox.