While out and about I overheard a conversation, “Its Stinkbug time, another six months of Stinkbugs.”
I must admit that the conversation was correct. The Brown Marmorated Stinkbug (Halyomorpha halys) is
notorious for invading homes in the fall as they start appearing on our doorsteps in search of winter
quarters. Other unwelcomed guests may include Boxelder Bugs (Boisea trivittatus); Western Conifer Seed
Bugs (Leptoglossus occidentalis); and Multicolored Asian Lady Beetles (Harmonia axyridis).
It is very hard to predict whether home invasions across Ohio will be high or low this year, or in any
given year. When the stinkbugs started appearing in Ohio, we braced for the stink bug tsunami to
inundate Ohio; however, it arrived more as a ripple than a wave. This is not to say there were no Ohio
homes with high numbers of stinkers, but home invasions seemed to trend downward rather than upward once
the bugs arrived in our state.
The other major invader is the Multicolored Asian lady beetles. They first became a problem in Ohio in
October 1993 when some residents reported that thousands of lady beetles were congregating on homes and
buildings, with many of these insects finding their way indoors. Populations remained high in Ohio
throughout the 1990s and into the 2000s.
Some connections have been made between high populations of soybean aphids (Aphis glycines), another
Asian invader, and elevated Asian lady beetle invasions in nearby homes. Of course, lady beetles love to
chow down on aphids and high numbers of the multicolored Asian lady beetle adults and larvae are common
in heavily infested soybean fields. According to Ed Lentz Ohio State University Extension Hancock County
Agricultural Educator, the soybean aphid population in NW Ohio fields has been low to nonexistent.
However, using the aphids as a predictor of lady beetle home invasions has not been entirely reliable.
Insect fall home invaders do not intend to trespass inside homes and other structures. In fact, those
that make their way into the interior spaces of homes are doomed. As with all insects, the survival of
home invaders is governed by a “cold-blooded” physiology meaning the speed of their metabolism is mostly
governed by ambient temperature. The higher the temperature, the faster their metabolism, and the faster
they “burn” fat. Yes, insects have fat, but it is confined by their hard exoskeletons, so they do not
suffer embarrassing expanding waistlines!
The home invaders feed voraciously in late summer to accumulate fat. They then seek sheltered locations
in the fall where cool temperatures slow their metabolism during the winter so they will not exhaust
their stored fat reserves. This survival strategy keeps them alive since there is nothing for them to
eat throughout the winter.
The insects are attracted to the solar heat radiating from southern or western facing roofs and outside
walls of our homes as well as the warmth radiating from within. This can lead them into attics, exterior
wall voids, and spaces around door jams and window frames. These all make perfect overwintering sites
and they stand a good chance of surviving the winter if they remain in these cool, protected locations.
However, they sometimes make a terrible error, for both the insect and the homeowner. Instead of staying
put, they continue to follow the heat source and enter homes. This is accidental and disastrous for the
insects because the high indoor temperatures cause them to burn through their fat reserves and starve to
death.
The best defense against home invaders found inside a home is to prevent them from entering in the first
place. An ounce of calking is worth a pound of bugs. Large openings created by the loss of old caulking
around window frames or door jams provide easy access into homes. Such openings should be sealed using a
good quality flexible caulk or insulating foam sealant for larger openings.
Poorly attached home siding and rips in window screens also provide an open invitation. The same is true
of worn-out exterior door sweeps including doors leading into attached garages; they may as well have an
“enter here” sign hanging on them. Homeowners should also venture into the attic to look for unprotected
vents, such as bathroom and kitchen vents, or unscreened attic vents. While in the attic, look for
openings around soffits. Both lady beetles and stink bugs commonly crawl upwards when they land on
outside walls; gaps created by loose-fitting soffits are gateways into home attics.
Insects that find their way into a home should be dealt with carefully. Swatting or otherwise smashing
these insects can cause more damage than leaving them alone since fluids inside their bodies can leave
permanent stains on furniture, carpets, and walls. Also, mashing multicolored Asian lady beetles and
brown marmorated stink bugs can release a lingering eau de bug; lady beetles have stinky blood, and
stink bugs are called stink bugs for a reason.
The best way to remove these invaders is to use a dustpan and broom. Gently sweep up the insects and dump
outside preferably away from the home. Vacuum cleaners and shop vacs present their own sets of risks if
used on stink bugs and lady beetles because the insects will release their defense odor in response to
swirling around inside the vacuum tank creating again a lingering eau de bug.
