Unwanted guests looking for winter homes

It is time for my annual reminder of unwanted guests coming to you soon. Insects that overwinter as adults will be looking for winter quarters with the colder temperatures. Many of these insects resided in the crop fields before the harvest and now they need a new place to live. Their movement is often noted after the first period of extended low temperatures in the thirties or after a fall warmup followed by chilly weather. Once a home has been targeted as desirable, a large number of these insects will try to move into a building 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 their invasion. The two most common insects that may invade homes are multicolored Asian lady beetles and marmorated stink bugs. Multicolored Asian lady beetle populations may be lower this year since soybean aphids, their favorite food, was not a problem in local soybean fields. These 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-shape), 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. Beetles can exude a foul-smelling substance that will stain fabric and material when threatened or crushed. They are not aggressive, but people have noted that their mandibles are large enough to feel a slight nip when handled, though it will not break the skin. Brown marmorated stink bugs populations have been increasing for the past several years and have become more of a nuisance than the Asian lady beetles. 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. The last nuisance invader is not an insect but an arthropod. Hundreds to a thousand millipedes can move into garages, ground level rooms and basements this time of year. People describe them as worms everywhere. They are about one inch long and pencil lead thick. Millipedes move slowly and often coil when touched. They don't bite but may stain fabric if crushed. Mulch near homes is often the source of millipedes. Millipedes move from areas heavily mulched looking for warming quarters once cold or wet fall weather moves into an area — managing the mulch depth near buildings is one method of limiting their numbers. Their populations may be reduced this year because of the extended dry spells this past summer and fall. The best defense against these invaders is to block entry points. Window screens will prevent entry even if many insects gather on them. However, worn-out exterior door sweeps and open garages allow easy passage. Exterior holes and cracks need to be sealed with caulk. Other insect exclusion methods include finding and sealing-off entry points such as cracks 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 inside the home, the best method to manage the offending invader is the vacuum or hand pick up, then deposit 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. Perimeter insecticides may be used, but may not be effective since the insects are not feeding and may not ingest the pesticide. In summary, invasive insects may be found around and in homes as temperatures drop the next several weeks. 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. Lentz is agriculture and natural resources educator with Ohio State Extension Office — Hancock County.