Overwintering Pests in Camden County: What's Hiding in Your Walls This Winter

What Overwintering Pests Are Doing in Camden County Homes

Every fall in Camden County, as temperatures drop below 50 degrees F, a specific group of insects seeks protected shelter to survive the winter. Your home's wall voids, attic spaces, and crawl areas provide exactly the insulated, stable environment they need. These overwintering pests — stink bugs, cluster flies, boxelder bugs, and multicolored Asian lady beetles — do not reproduce indoors, do not damage your home's structure, and are not dangerous. But they arrive in enormous numbers, create significant nuisance, and emerge again as indoor pests in late winter and early spring as they try to exit. Understanding what is inside your walls helps you manage the situation more effectively than reaching for a spray can.

Brown Marmorated Stink Bugs

Brown marmorated stink bugs are the most numerous overwintering pest in Camden County. They release aggregation pheromones that guide hundreds of additional bugs to the same entry points, which is why the same homes in Cherry Hill, Voorhees, Haddon Township, and Collingswood get hit year after year. Stink bugs enter through any gap larger than 1/8 inch — siding overlaps, window frame gaps, pipe penetrations, soffit intersections, and attic vents. Inside your wall voids and attic, they remain dormant through the coldest months, then become active again when warm days arrive in late February and March. Most homeowners discover the extent of their stink bug infestation when bugs begin emerging on warm winter days through light fixtures, window frames, and baseboards as they attempt to exit.

Cluster Flies

Cluster flies (Pollenia rudis) are a common but often unidentified overwintering pest in older Camden County homes, particularly in Haddonfield, Collingswood, and Audubon. They are larger and slower than house flies, with a distinctive golden sheen on their thorax. Cluster flies are parasites of earthworms during summer months and enter homes in fall in large numbers, congregating in attic spaces and upper wall voids. They become active on warm winter days and often cluster at south-facing windows inside attic spaces. Finding groups of lethargic, slow-moving flies at windows in December or January is a reliable cluster fly indicator.

Boxelder Bugs and Asian Lady Beetles

Boxelder bugs (black with red markings) and multicolored Asian lady beetles are common overwintering pests in South Jersey neighborhoods with mature boxelder, maple, and ash trees — including throughout Cherry Hill, Voorhees, and Gloucester Township's established suburban areas. Like stink bugs, they aggregate on south- and west-facing exterior walls on warm fall days before seeking wall void entry points. Inside, they cause the same pattern of dormancy through winter followed by emergence in late winter. Asian lady beetles can bite when handled and release a foul-smelling defensive secretion, making them more genuinely unpleasant to deal with than stink bugs or cluster flies.

Why Mice Enter at the Same Time

Fall is when overwintering pests compete for the same real estate as mice. The entry points that stink bugs and cluster flies exploit in October are the same gaps that house mice use to enter Camden County homes from November onward. If you are seeing overwintering pest activity around your windows, soffits, and foundation, you are seeing the same vulnerability that mice will use. Sealing those entry points in late summer — before the fall invasion begins — addresses both problems simultaneously.

What to Do About Overwintering Pests Already Inside

Professional exterior treatment applied in early September, before overwintering pests begin massing on south-facing walls, provides the most effective prevention. Residual products applied to entry-point areas intercept bugs before they enter. For pests already inside wall voids, a vacuum with a bag or filter that can be immediately sealed and discarded is more appropriate than spraying — killing stink bugs with aerosol releases their defensive odor indoors. For large populations already established in attic spaces, professional void treatment with dust formulations in late fall reduces the number emerging in late winter.

Call Camden County Pest Control at (856) 600-0812 to schedule fall overwintering pest prevention treatment for your Cherry Hill, Voorhees, Collingswood, or Haddon Township home before the fall invasion begins.