Fall Home Invaders
 | Author:
Allison Kosto, MSU Broadwater County Extension Agent
MSU Broadwater County Extension Agent |
Fall Home Invaders
Allison Kosto
MSU Broadwater County Extension Agent
What is it about insects and spiders that can cause a sense of panic?! There is a certain quality to these creepy crawlies that can do that! During the fall, it is common to see an increase in insects and spiders in the home. Most of the time they are harmless but can be a nuisance. Here are a few common fall home invaders.
Boxelder Bug
Most people are familiar with the classic black and red boxelder bug. They overwinter in protected places such as homes. Although they do not cause any major damage, they can stain draperies or light-colored surfaces and produce an odor when crushed. They have been reported to bite humans on rare occasions. Removing female boxelder trees close to your home is the best solution. If there are other boxelder trees in your neighborhood or area, you may still see some bugs, but it can reduce the population at your house. Sealing cracks into the home is also important. Most insecticides for the exterior of homes are not very effective against the boxelder bug.
Cluster Flies
These are the most common flies found indoors during the cool season. They resemble a house fly, only slightly larger with gold hairs on their abdomen. During the summer, cluster flies feed on earthworms. They use buildings for winter shelter but don’t reproduce there. You will often see them congregate or “cluster” on sun-warmed buildings from mid-August to October. In the fall, flies enter a dormant state and remain inactive until spring. However, if there is a warm spell during winter, you might see a fly temporarily come out of dormancy in the house. Check window and door seals, ventilation openings and siding to help prevent them from getting into your home. Insecticides can be sprayed in and around the cracks and crevices of your home. Custer flies are not attracted to most traditional fly traps.
Western Conifer Seed Bug
This insect is often mistaken for an assassin bug. They have a similar body shape to a boxelder bug, but with a brown body, a unique pattern and thick hind legs. They have a defensive odor when disturbed. Just like the other insects, they are seeking shelter for the winter. These bugs feed on trees and shrubs with a preference for pines. They do not bite people or harm homes or household items. They often die in a week or two if not allowed to drink water and can be vacuumed or swept up.
False Chinch Bugs
These insects are not as common. During the summer, false chinch bugs feed by sucking sap from plants. They favor plants in the mustard family such as radish, canola and mustard weeds. They are particularly fond of flixweed, a common mustard weed. Mass migrations happen in late summer during periods of hot, dry weather. They seek shelter and areas of higher humidity. They do not bite or damage anything indoors. They will eventually die if trapped inside. Irrigated yards may encourage false chinch bugs, so stop watering next to your home if you start to have a problem. Insecticides have little to no effect. Migrations usually only last a brief time.
Spiders
Just like insects, many spiders seek a protected place to spend winter. The only spider in Montana of medical concern is the black widow. The brown recluse is a concern in the southeastern United States but is not found in Montana where it cannot survive the winters. There is older literature that indicates the hobo spider is poisonous and can cause necrotic lesions, similar to the brown recluse. However, recent scientific evidence suggests this is not true. The hobo spider and other insects and spiders can bite, although rarely. Most do not inject venom. However, bites can cause irritation or soreness (like a mosquito) and are subject to infections. Even though spiders may be an unwanted guest in your home, they can reduce pests. If you are concerned about spiders, take caution working in crawl spaces, garages and undisturbed parts of your house. Keep habitats such as wood piles and debris away from the house. In your home, sweep or vacuum them up. You can also purchase spider traps.
Fall home invaders are certainly a nuisance but are typically a short-lived problem. Check your home and seal cracks to reduce their presence. If you need assistance with insect or spider identification or control, contact your local Extension Office at 406-266-9242. Photographs and physical samples are welcome!
