As the cold weather months approach, insect pests will begin looking for shelter from the winter weather, and many of them could very well end up in your home.
Overwintering pests have some things in common:
- If you see one or a few, there are typically more nearby.
- While adult overwintering bugs rarely eat indoors during the cold weather, they may frequently be found near houseplants in search of water.
- Once they are indoors, you can spot treat for them by vacuuming or sweeping them up, or by otherwise physically removing them. Insecticides can help for spot treatment. Be sure to empty your vacuum cleaner bag afterward, because in most cases, overwintering pests won’t die from being vacuumed up and will just crawl right back out.
- Their populations vary from year to year, depending on existing conditions, and they are not necessarily a big problem each year.
The most common overwintering insect pests include:
What do stink bugs look like?
Brown Marmorated Stink bugs are typically grayish-brown in color with white striping, have six legs, are around ½” long, and triangular or shield-shaped.
They are an invasive species from Asia, and like to spend most of their time outdoors.
Stink bugs are also distinguishable by the unpleasant odor they emit when threatened, comparable to strong herbs and spices like coriander or cilantro. They can emit this scent for up to several inches away from their bodies.
Adult Stink bugs are agile flyers and they are typically first noticed in the fall when they begin heading indoors (large numbers of dead stink bugs are an indication of an infestation problem).
Where can you find Stink bugs?
They can easily be found enjoying the warmth on the sunny side of structures and in other warm places indoors, so check your kitchen, furnace room, attic, other warm rooms, and rooms in your home that get a lot of sunshine.
What do Stink bugs eat?
They feed on crops typically but indoors are known to feed on ornamental plants, and fruits such as peaches and apples.
How to treat for Stink bugs:
Tips for preventing overwintering pests from coming in your home for the cold weather are below. You can spot-treat for Stink bugs with an indoor bug spray. You can also use a residual spray around your home’s perimeter as a preventive measure.
Asian Lady Beetles
What do Asian Lady Beetles look like?
Most people are familiar with Asian Lady beetles, and with their small half-hemisphere body shape, black-spotted red/orange shell, and dark heads with white spots that look like “eyes” (similar to Ladybugs). They typically measure about 1/3” - 3/8” in length and are found all over the U.S. and Canada and harmless for the most part, but can become a nuisance in large numbers.
As a defense, they exude a thick, dark liquid from their leg joints that has a foul odor and can stain. The multi-colored Asian lady beetle is also known to aggravate asthmatic symptoms and cause allergic reactions in some individuals.
Where can you find Asian Lady Beetles?
During warm weather months, Asian Lady beetle populations grow because of the green foliage and abundant aphids outdoors. In the fall, adults will seek out protected areas to spend the winter (overwinter). Favorite outdoor overwintering areas include underneath rocks, leaves, and landscaping timbers. Some Asian Lady beetle species are known to head indoors into homes and other buildings.
Indoors, check your kitchen, furnace room, attic, other warm rooms, and rooms in your home that get a lot of sunshine.
What do Asian Lady Beetles eat?
Asian Lady beetles are mostly considered beneficial, as they aggressively prey on plant-eating insects (e.g., aphids, mealybugs, mites, etc.) which can harm crops and garden plants. A few Asian Lady beetles are considered destructive, as they feed on plants (e.g., Mexican Bean beetle, squash beetle).
How to treat for Asian Lady Beetles:
Tips for preventing overwintering bugs from coming in your home for the cold weather are below. You can spot-treat for Asian Lady beetles with an indoor bug spray. You can also use a residual spray around your home’s perimeter as a preventive measure.
Boxelder Bugs (a.k.a. Firebugs)
What do Boxelder bugs look like?
Boxelder bugs are black with fiery red/orange striping on their backs. Adults are flat, oval-shaped, and measure about 1/2” long. Nymphs look very similar to their adult counterparts, but are bright red in color.
Boxelder bugs get their name from their most often being found on and near boxelder trees. Boxelder bugs can be found wherever boxelder trees grow, including the western U.S., as well as in the eastern states and eastern Canada. They are considered a nuisance pest and are the most common overwintering pest inside homes, sheds, garages, etc. Their waste can cause a red stain on curtains, upholstery, clothing, etc., and when crushed or frightened, boxelder bugs can emit a pungent, unpleasant odor. They occasionally bite when you pick them up, and the bite mark may get red and irritate your skin.
Where can you find Boxelder bugs?
Outdoors, in the spring through the fall, Boxelder bugs typically gather wherever they can find sunlight. Before heading indoors for the winter, they usually gather on warm spots on and around buildings. Indoors, they are known to hide in wall voids, cracks, and crevices to protect themselves from the cold. In late March to early April, they are more visible as they leave their winter hideouts to return to their favorite trees until the cold weather returns.
Indoors, also check your kitchen, furnace room, attic, other warm rooms, and rooms in your home that get a lot of sunshine.
What do Boxelder bugs eat?
Boxelder bugs mainly eat boxelder tree seeds as well as the new boxelder leaves. They also may feed on fruits like apples and plums.
How to treat for Boxelder bugs:
Tips for preventing overwintering bugs from coming in your home for the cold weather are below. You can spot-treat for Boxelder bugs with an indoor bug spray. You can also use a residual spray around your home’s perimeter as a preventive measure.
What do Cluster flies look like?
Cluster flies are typically dark gray in color and around 3/8” in length. You’ll know you’re dealing with Cluster flies if you see flies indoors during the winter, as few flies are found indoors during the cold weather.
Where can you find Cluster flies?
Cluster flies are attracted to light, and you will typically find them indoors in upstairs rooms and attics, as they will continue heading upward until they can’t get any higher up. You will also typically find them in window sills.
What do Cluster flies eat?
Cluster fly larvae feed on earthworms outdoors in the summer, and adult Cluster flies do not eat indoors during the winter.
How to treat for Cluster flies:
Tips for preventing overwintering bugs from coming in your home for the cold weather are below. You can easily use a fly swatter and flypaper to manage Cluster flies, and also spot treat for them with an indoor fly spray or use a residual spray for preventive maintenance.
How To Prevent Overwintering Pests
The prevention steps below apply to all overwintering pests:
- Caulk and seal all holes, cracks, crevices in your foundation and around doors, and windows, etc.
- Make sure screens, weatherproofing and door/window seals are in good repair.
- Fill holes around utility lines.
- Install door sweeps on exterior doors.
- Seal up:
- Door/window frames
- Roof lines
- Soffits/attic vents
- Chimney flashing
- Reduce exterior lighting that attracts overwintering insects
- Cut back vegetation 1-2 feet from exterior
- Keep firewood at least 20 feet from house and elevate if possible
- Place mesh screens on foundation or attic vents
Perimeter insecticides can help throughout the summer and fall as a protective barrier. You can spot-treat indoors for overwintering pests with Maggie’s Farm Home Bug Spray, Maggie’s Farm Ant & Roach Killer, and Maggie’s Farm Flying Insect Spray (for Cluster flies).
Another valuable treatment involves applying an insecticide dust to potential pest entry points around your home (cracks, crevices, weep holes, utility entry points, etc.) for long-lasting repellency and control.
More things you should know about overwintering pests:
What are Boxelder bugs attracted to?
Boxelder bugs like Boxelder trees for its harborage, seeds, and leaves. They will also feed on maple and ash trees. They like areas with warmth and will be attracted to buildings with plenty of southern and/or western exposure.
How do you get rid of Boxelder bugs?
The best way to minimize Boxelder bugs is to prevent them from coming inside to begin with. You can make sure doors, windows, and screens are in good repair, and also make sure that cracks, crevices, and other possible entry points, etc. are sealed/covered to keep them and other bugs out. You can also spray a perimeter insecticide spray. Once inside, you can vacuum them up or otherwise physically remove them.
What causes Boxelder bugs in the house?
A combination of easy access into your home and the proximity of boxelder trees in your yard or neighborhood will make conditions ideal for them to get indoors. They also love to be warm and are drawn to structures with southern and/or western exposure, which create plenty of outdoor areas to sun themselves in the summer and fall.
How do you get rid of Boxelder bugs without chemicals?
Once boxelder bugs are indoors, the easiest way to get rid of them is to physically remove them or vacuum them up. To prevent them from getting in, make sure that all window and door screens and weatherproofing are all in good repair, and seal/cover up as many outdoor cracks/crevices as you can.
Why do I have so many Asian Lady beetles in my house?
Asian Lady beetles are attracted to light-colored homes (particularly older homes with plenty of cracks and crevices) and they are also attracted to the warmth that reflects off of lighter colors. They are also drawn to homes with natural wood siding, and homes in wooded areas. Asian Lady beetles are harmless but can become a nuisance when they show up in larger populations. They can also be difficult to get rid of. The best way to prevent them and other overwintering pests is to make sure your home is well screened/covered/sealed up to minimize ways that they might be able to get inside.
What causes Asian Lady beetle infestations?
Asian Lady beetles normally hibernate during the winter inside caves, underneath rocks, inside rocky crevices, etc. They are also known to find shelter inside our homes. They love the warm sun and other warm places, particularly light-colored homes, homes with natural wood siding, homes in wooded areas, and older homes with plenty of cracks and crevices for harboring themselves.
They are harmless and don’t cause structural damage, but an indoor infestation can definitely become a nuisance. Similar to ants, they leave behind them trails of pheromones, to help them come back and find the same places every year. Ease of access into your home through cracks, crevices, unscreened windows, etc. is the quickest way to spark an Asian Lady beetle infestation.
What do Asian Lady beetles eat inside the house?
Asian Lady beetles are beneficial insects and help reduce the populations of aphids and other insects/larvae that damage plants. They also eat pollen and nectar, as well as mealy bugs, scales, mites, leafhoppers, and other soft-bodied insects.
In the winter, they don’t eat anything. They’re only inside for protection from the winter weather elements, so they can hibernate.