Boxelder Bug Invasion: What Michigan Homeowners Need to Know This Fall

If you live in Metro Detroit, Ann Arbor, or anywhere in Southeast Michigan, you’ve probably seen them: clusters of black-and-red bugs lounging on your siding, windows, or porch this fall, congratulations—you’ve met the boxelder bug. These are boxelder bugs, and thanks to warmer-than-average fall weather, they’re still active in November 2025—and they’re looking for a cozy place to overwinter. 

"Boxelder Bug on Siding" – Source: Pest Pros of Michigan

What Are Boxelder Bugs, Anyway?

These almond-shaped insects, formally known as Boisea trivittata, are native to North America and especially fond of Southeast Michigan’s boxelder, maple, and ash trees. They’re about ½ inch long, black with red-orange markings, and they don’t bite, sting, or damage your home’s structure. But that doesn’t mean they’re welcome guests.

Why They’re Invading Southeast Michigan Homes This Fall

Boxelder bugs are sun-seekers. As temperatures drop, they gather on warm, sunny surfaces—especially the south and west sides of homes. From there, they slip through tiny cracks, vents, and gaps to overwinter in attics, basements, and wall voids. Once inside,they stick around until spring, occasionally popping out on warm winter days.

Fun Fact: Boxelder bugs can fly up to 2 miles to find shelter. Now, that’s dedication!

Current Situation 

• Boxelder bugs usually show up in late September through November, with their peak activity in October. Normally, they start disappearing as temperatures drop—but this year is different. Record-breaking warmth across Michigan has kept them active longer than usual, and now they’re still swarming homes well into November.
  
  

Are Boxelder Bugs Dangerous? 

Nope! They don’t bite or sting. But they can be annoying. When crushed, they release a foul odor and leave behind reddish stains—especially on light-colored walls, curtains, and furniture. 

What Happens If Pets Eat Them?

• Most pets will spit them out because they taste extremely foul.
• If your pet does swallow a boxelder bug, they can cause mild gastrointestinal upset like:
  • Vomiting
  • Diarrhea
  • Drooling
• These symptoms are usually short-lived and not dangerous.
  
  

What Should Pet Owners Do?

• If your pet eats one or two bugs, monitor for symptoms.
• If vomiting or diarrhea persists, or if you notice signs of distress, contact your veterinarian.

Why You Shouldn’t Just Ignore Them

Even though they’re not dangerous, boxelder bugs are a nuisance—and here’s why:

1. They Invade in Huge Numbers

Boxelder bugs don’t come solo—they come in swarms. Homeowners across Southeast Michigan are seeing hundreds to thousands of these bugs clustering on sunny walls, windows, and siding (especially the south and west sides of homes). Once inside, they can hide in attics, wall voids, basements, and crawl spaces, making them hard to fully remove.

2. They Stain Everything

Boxelder bugs may not bite, but they definitely leave their mark—literally. When crushed or even disturbed, they release a rust-colored excrement that can stain just about anything it touches.

You might find these stubborn stains on:

• Walls
• Curtains
• Upholstery
• Carpets
• Clothing

These marks are especially noticeable on light-colored fabrics and surfaces, and they’re tough to clean. 

3. And Yes—They Smell, Too

As if the stains weren’t enough, boxelder bugs also come with a musty, foul odor. When squished, they release a scent similar to stink bugs. If you vacuum them without a sealed bag, that smell can linger in your vacuum and spread throughout your home.

So not only do they stain your stuff—they stink up your space. The best way to deal with them? Vacuum carefully, empty the contents outside, and clean your vacuum filter with warm, soapy water. 

4. They Can Attract Other Pests

The entry points they use—the tiny cracks, gaps, and vents—can become open doors for other pests. Once these bugs find a way in, they unintentionally highlight weak spots in your home’s exterior. And guess what? Other pests are watching. These same entry points can attract:

• Stink bugs
• Spiders
• Rodents
• Ants
• Cockroaches
  

5. They Can Cause Allergic Reactions

In large numbers, their droppings and body parts can cause respiratory irritation or allergic reactions. 

6. They’re Persistent

Even if you remove them, they come back year after year unless you take preventive action. They overwinter in homes and reappear on warm winter days, crawling out of vents, light fixtures, and window frames.

How To Keep Boxelder Bugs Out of Your Home

Here’s your fall checklist to stop these freeloaders from moving in:

Vacuum Them Up

• Use a vacuum to remove bugs indoors—avoid squishing them to prevent stains and smells.

• Empty vacuum outside immediately then  Clean filters with warm, soapy water.  
  

Keep It Clean

• Wash exterior walls with soapy water to remove bug-attracting residue.

Seal Entry Points

• Caulk cracks around your windows, doors, and siding.

• Install weather stripping and door sweeps.

• Repair screens on your doors and windows. 

• Screen off vents and utility openings.
  

DIY Bug Spray

• Mix water with a few drops of dish soap in a spray bottle. 

• Spray directly on bugs outside—this dehydrates them safely.

How to Remove Boxelder Bug Stains

If these little critters have already left their mark, don’t panic—here’s how to tackle stains on different surfaces:

• Walls & Hard Surfaces: Start with warm water and mild dish soap. For stubborn spots, apply a baking soda paste and gently scrub.
• Upholstery & Curtains: Blot the stain using a mix of white vinegar and water, then rinse with clean water. Avoid rubbing, as it can spread the stain.
• Carpet: Use a carpet-safe enzyme cleaner or a solution of hydrogen peroxide and dish soap. Always spot test first to prevent discoloration.

Quick tip: Act fast! The sooner you treat the stain, the easier it is to remove.

Time to Call Safari Tree

If your home looks like a boxelder bug convention, it’s time to call in the pros. Safari Tree offers:

• Targeted treatments
• Barrier sprays
• Entry point sealing
• Eco-friendly options

We service Southeast Michigan and can help you reclaim your home from these persistent pests.

 Need Help? Contact Safari Tree Today!

Let’s kick those bugs to the curb. Call us or visit safaritree.com to schedule your fall pest control service.