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The Unwanted Guests

story and photograph by Steven Jakobi

The western conifer seed bug.

Autumn is a time for the arrival of a bunch of unwanted guests to the house. In reality, they are more like squatters, moving in for the winter. I am not talking about people but about insects, mammals, and other creatures. Field mice and shrews may inundate the basement and even an enterprising snake or two may set up shop in the dark corners of the cellar or porch of an old house.

Old or new, many homes are invaded by several kinds of insects looking for a place to ride out the cold months of winter. In my house, a large portion of which was built in the 1840s, we have to deal with cluster flies, Asian lady beetles, and western conifer seed bugs, the latter of which are often confused with the marmorated stink bug. Other folks I know also have occasional infestations by boxelder beetles.

All of these insects can be a nuisance if their numbers are big enough. Their populations may fluctuate from year to year, depending on a number of environmental and control factors, but in some years there may be hundreds or even thousands attempting to enter homes. Mind you, none come to eat or reproduce. They are simply searching for a suitable place to bide their time until the warmer months of next spring.

Of the insects I listed above, the most loathed species is the cluster fly. Slightly larger than house flies, they spend the summer months parasitizing earthworms during their larval development. In autumn, they enter homes through cracks or crevices and set up shop in any dark part of the house. These hiding places may be in walls, dark ceiling corners, base boards, or even behind curtains. If they are numerous enough, they may buzz around the house and occasionally fall into food, clothing, bedding, or even people’s hair. They can be quite a disgusting nuisance. Unlike the house fly, cluster flies do not eat or reproduce in the home and they don’t carry disease-causing germs. The best remedy is to keep them out in the first place by sealing any openings around doors or windows and caulking tiny crevices. However, this is easier said than done, especially in older dwellings. Once they are inside the house, the vacuum cleaner is the homeowner’s best friend. If there’s an annual influx a professional exterminator’s equipment and chemicals might be called upon to help prevent the entry of these flies. The use of over-the-counter insecticides is not recommended as an effective control measure.

Multicolored Asian lady beetles were brought to North America from Japan as biocontrol agents of aphids and scale insects in southern forests and fruit orchards. Another group of these beetles was accidentally introduced in shipping containers in the port of New Orleans, and they have since been spreading throughout the eastern part of the U.S. In New York, they were first recorded in Chemung County in 1994. Often mistaken for the common ladybug, this species invades homes in October or November and can congregate by the hundreds in ceiling corners, porches, or other structures. These lady beetles may range in color from pale yellow to dull red, and normally have numerous black spots on their bodies. Like cluster flies, the lady beetles do not eat or reproduce during the winter months. Many will die from the low humidity in our heated homes and litter carpets, floors, or tops of cabinets, but the majority simply leave the home when the weather turns warm. Control measures are pretty much the same as for the cluster fly: exclusion and the vacuum cleaner. The use of insecticides is not recommended by Cornell University entomologists.

For the past three or four years, I have had another group of unwanted guests: the western conifer seed bug. These insects are often misidentified as “stink bugs.” To be sure, they do produce a strong odor when handled improperly, but they are not related to the marmorated stink bug. A western North American native, the conifer seed bug has spread eastward and was first recorded in New York State in 1992. During the summer, they feed on the cones and seeds of pines, spruces, firs, and hemlocks. In the fall, they enter dwellings but they neither bite nor sting nor cause any damage. Because of the smell these beetles can give off when injured, some people prefer to handle them with paper towels or disposable gloves. Adults are about three-quarters of an inch long, slender with brown stripes and a darker abdomen. They have characteristic bumpy enlargements on their hind legs (see photograph), which easily distinguishes them from the shorter and wider marmorated stink bug. I don’t mind these beetles too much in the house, although they occasionally startle one of us in the bathroom or in the kitchen. For folks who do not care to have them at all in the house, exclusion is once again the best practice. The same goes for the boxelder beetle, a similarly shaped bug with handsome red-and-black coloring that is frequently encountered in areas where boxelder trees (a kind of maple) are common.

Living in the suburbs or in the country, we have to contend with all kinds of wildlife—from mammals, like deer and skunks, to a variety of birds, insects, reptiles and amphibians. It is a constant “battle,” although we might remember that these creatures need pretty much the same things we do: food, water, and shelter to protect them from the bitter cold months of western New York’s harsh winter climate.


Steven Jakobi is a Master Gardener volunteer for the Allegany County Cornell Cooperative Extension.

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