What Are Fall Invaders?

 

"Fall invaders" is a term used by pest control professionals to describe certain types of insects and occasionally other small animals that try to get inside homes and buildings as the weather gets cooler in the autumn (fall) months. These pests are not trying to harm people, spread disease, or attack your property, but mainly are looking for a warm, sheltered place to survive the winter. Once they get inside, they can become a nuisance—even if they usually don’t reproduce or feed much indoors.

 

Which Pests Are Considered Fall Invaders?

 

Some of the most common fall invaders include:

• Boxelder Bugs: Black bugs with reddish-orange lines on their bodies, often found in large groups on sunny sides of buildings.
• Asian Lady Beetles: Often mistaken for ladybugs, these are orange to red beetles with or without spots.
• Stink Bugs: Brown, shield-shaped bugs that release a foul odor if crushed or disturbed.
• Cluster Flies: Large, slow-moving flies that gather in groups, often seen on windows or walls.
• Western Conifer Seed Bugs: Long-legged brown bugs, easily mistaken for stink bugs.

While these are the most common, other critters like spiders, ants, and even rodents may also use the same behavior—seeking shelter indoors in the fall.

 

Why Do Fall Invaders Enter Buildings?

 

These pests can’t survive cold temperatures well, so their natural instinct is to find a protected space as summer ends and temperatures start to drop. They are attracted to the warmth of buildings, especially sunny, south-facing walls, and will squeeze through cracks, gaps, holes, doors, and windows to get inside. Sometimes they hide within walls or attics and may remain mostly hidden until spring.

 

Are Fall Invaders Harmful?

 

Generally, fall invaders are not dangerous. They do not bite, sting, spread disease, or generally cause structural damage to your home. However, they can become a big nuisance due to their large numbers and their presence around windows, walls, or even emerging inside rooms during sunny winter days. Some, like stink bugs and lady beetles, may emit odors or leave stains if crushed.

 

Preventing Fall Invaders

 

The best way to manage fall invaders is to prevent them from entering your home in the first place. Effective prevention steps include:

• Sealing cracks and gaps around doors, windows, siding, utility pipes, and rooflines with caulk or weather-stripping.
• Repairing or replacing damaged screens on doors and windows.
• Adding door sweeps to all exterior doors.
• Inspecting and repairing attic and foundation vents, chimneys, and soffits.
• Keeping outdoor lights off or using yellow "bug" bulbs, as standard lights can attract these pests.

Most pesticides and sprays are not recommended indoors for these pests since they don’t reproduce inside and are best managed through exclusion (keeping them out).

 

Dealing with Fall Invaders Already Inside

 

If fall invaders have made it indoors, the best removal method is usually physical, such as:

• Vacuuming up insects (empty the vacuum bag or canister right away to prevent odors).
• Using a broom and dustpan to sweep them up and release them outside, if practical.

Avoid smashing insects like stink bugs and lady beetles, as they can leave smells or stains. Remember, these pests are mainly dormant inside, so once spring arrives, they typically try to leave the building.

 

When to Call a Professional

 

If you have significant infestations or recurring issues, a pest control professional can help identify entry points, advise on sealing your home, and use targeted treatments if needed. However, prevention is almost always more effective and safer than treating after the pests are inside. If you act before fall, you can stop most fall invaders before they become a problem.