When nights cool off in September and October, mice, stink bugs and spiders look for a warm place to spend the winter. The gaps you seal now decide how many get in.
Why fall matters
Cooler nights send pests looking for shelter, and your house is the warmest option around. Mice come in from fields and woods, stink bugs gather on sunny walls, and spiders follow the insects indoors.
Delaware homes near farm fields and wooded lots often see the most pressure. Doing the work in early fall, before the first hard cold, gives you the best chance of keeping them out.
Spiders are not usually the main concern, but they follow other insects indoors. If you are seeing a lot of them, that is often a clue that something else is feeding them.
Seal the outside
Walk the house and look for gaps around pipes, cables, dryer vents and the AC line. Fill small gaps with caulk and larger ones with steel wool and sealant. A mouse fits through a hole the size of a dime.
Add door sweeps to exterior and garage doors. If you can see daylight under a door, pests can get in.
Look at the roofline and where utilities enter the house. Mice are good climbers, and gaps up high are just as useful to them as gaps at ground level.
Use materials that gnawing animals cannot chew through, such as steel wool or metal mesh, with sealant to hold them in place.
A flashlight helps. Check at night from inside a dark garage to see light coming in from outside.
Windows, screens and vents
Repair torn screens and re-caulk window frames, especially on south- and west-facing walls where stink bugs gather in the afternoon sun. Check weatherstripping on doors and windows while you’re there.
Make sure attic, soffit and crawl-space vents have intact screening. These are common entry points that are easy to overlook.
Do not forget the garage. A garage door that does not seal along the bottom or sides is one of the most common mouse entrances.
Around the foundation
Rake mulch back a few inches from the foundation, stack firewood away from the house and off the ground, and trim shrubs and branches that touch the siding. Branches can act as bridges for pests and squirrels.
Clean gutters so water drains away from the house. Damp soil near the foundation attracts insects and can cause wood problems over time.
Keep leaf litter and debris from piling up against the house. It holds moisture and offers shelter to many pests.
Look at the crawl space or basement after heavy rain. Standing water and damp soil attract insects and can lead to bigger problems.
Inside the house
Store pantry food, birdseed and pet food in sealed containers. Don’t leave pet bowls out overnight.
Set a few snap traps along garage and basement walls in October so you know early if mice are getting in. Place them against walls, where mice tend to travel.
Check the corners of the basement and storage areas. Cardboard boxes make cozy nests, and plastic bins with tight lids are a better choice.
Keep a small kit of caulk, steel wool and a caulk gun handy so you can fix gaps right when you spot them.
What to do about stink bugs
If stink bugs get inside, vacuum them up rather than crushing them, since they release an odor when disturbed. Empty the vacuum outdoors afterward.
Sealing gaps before they arrive is the best defense. A late-summer exterior treatment can also reduce the number that make it indoors.
If you find them in large numbers, a vacuum with a bag you can seal works best. Empty the vacuum outdoors afterward.
Signs you need help
Scratching in walls or the attic, droppings, gnawed packaging or a musty smell are signs of rodents. Large clusters of stink bugs on the siding mean more are probably trying to get in.
Do the walk-around once now and again in late winter. Seeing what changed is a good way to find new gaps.
- Scratching or scurrying sounds, especially at night
- Droppings in cabinets, garages or attics
- Dozens of stink bugs gathering on walls or windows
- Grease marks along baseboards
When to call a pro
If you notice any of the signs above, a fall exclusion visit from Mosquito & Pest Authority is cheaper than a winter of trapping. They serve all three Delaware counties and can find entry points you might miss, then recommend a plan using EPA-registered products applied according to the label where needed. Call 302-242-5254.
Common questions
When should I start fall pest-proofing?
Early fall is a good time, before nights turn consistently cold. Sealing gaps in September gives you a head start on mice, stink bugs and spiders.
Do I need traps if I have sealed my house?
A few snap traps along garage and basement walls are a useful early warning. If you catch nothing, that is a good sign your sealing is working.
Why do stink bugs gather on one side of my house?
They are drawn to warmth, so south- and west-facing walls that get afternoon sun are common gathering spots. Sealing gaps on those sides helps most.