Hello Lynda,

Below is a clear, Michigan‑specific, research‑based guide to where these insects get in, why they show up, and what actually works to prevent them, using only .edu sources you requested. I’ll also help you decode the mystery of “tiny black flying bugs” and talk about spiders.

Where They’re Getting In (General Principles)

Most Michigan home‑invading insects enter through:

Gaps around windows, siding, soffits, fascia, and rooflines

Cracks around utility penetrations (cables, dryer vents, AC lines)

Door sweeps that don’t fully seal

Gaps around attic vents or ridge vents

Double‑hung window pulley openings in older homes - More information at this link:

Boxelder Bug - Plant & Pest Diagnostics

Unsealed baseboards, outlet boxes, and light fixtures that connect to wall voids - More information at this link:

Boxelder Bug - Plant & Pest Diagnostics

Most fall‑invading insects don’t breed indoors—they overwinter in wall voids and accidentally wander into living spaces.

Boxelder Bugs (Year‑Round Sightings)

Why They’re in Your House

They invade in the fall to overwinter in walls and attics.

You keep seeing them year‑round because they’re already inside the structure and wander out on warm days.

How They Get In

Cracks around siding, windows, soffits, and attic areas.

Pulley openings in older double‑hung windows. How to Reduce Them

Seal exterior cracks with caulk (especially south & west walls).

Seal interior cracks around outlets, switches, and baseboards to keep them from being trapped in the walls.

Remove nearby female boxelder trees, if possible (a major attractant).

Vacuum them—don’t crush (they stain).

Exterior insecticide sprays in September can help, but are only moderately effective.

Stink Bugs (Summer → Fall, Invaders)

Why They’re in Your House

Brown marmorated stink bugs (BMSB) seek shelter in the fall and may appear indoors later.

How They Get In

Same entry points as boxelder bugs: siding gaps, soffits, window frames, attic vents.

How to Reduce Them

Seal exterior cracks (especially wooden siding).

For vinyl siding, sealing is less effective—bugs slip behind panels—so seal interior wall openings too.

Sweep or vacuum; avoid squishing (odor + staining).

Light traps do work indoors for stink bugs.

Grasshoppers in the Basement (Spring & Summer)

Why They’re in Your House

Grasshoppers don’t seek homes intentionally—they hop or crawl in through ground‑level gaps.

Entry Points

Gaps under basement doors

Cracks in foundation walls

Torn window screens

Gaps around crawlspace vents

What Helps 

Install tight door sweeps on basement/garage doors.

Seal foundation cracks.

Replace or repair screens.

Reduce tall grass or weeds near the foundation (they jump from vegetation).

(Grasshoppers aren’t typically covered in MSU home‑invasion articles, but these entry points are consistent with entomology extension guidance.)

Tiny Black Flying Bugs (Kitchen + Upstairs Windows)

You ruled out fruit flies and fungus gnats. Based on Michigan patterns, the most likely candidates are:

1. Dark-winged fungus gnats (but you said no plants)

Still possible if:

Moist organic matter exists in sink drains, garbage disposal, or damp areas.

2. Drain flies (moth flies)

Found near sinks, tubs, and floor drains.

It often appears even in clean homes if organic film builds up.

3. Black scavenger flies (Sepsidae)

Attracted to decaying organic matter, garbage bins, or even dead insects in window tracks.

4. Phorid flies

Can breed in hidden moisture, wall void leaks, or under appliances.

Where They Come From

Window tracks with dead insects (common with boxelder/stink bugs)

Sink drains (biofilm)

Moist wall voids (slow leaks)

Basement floor drains

What Helps

Clean drains with a brush + boiling water (not chemicals).

Remove debris from window tracks.

Check for moisture leaks under sinks or behind dishwashers.

A plug‑in light trap can help identify and reduce them, but won’t solve the source of the problem.

If you want, you can describe the bugs (size, behavior, shape), and I can help narrow it down.

️Spiders (Lots of Them)

Why do you have many

Michigan homes with lots of insects (boxelder bugs, stink bugs, flies) naturally attract spiders—they’re following the food.

Cleanliness doesn’t affect spider presence; insect availability does.

What Helps Reduce (Not Eliminate) Spiders

Reduce other insects (your main issue).

Seal gaps around windows and doors.

Vacuum webs and egg sacs regularly.

Reduce clutter in basements and storage areas.

Spiders are beneficial, but if you’re seeing many, it’s a sign that entry points for insects are still open.

How to Systematically Find Entry Points

Exterior Checklist

Walk around your home on a sunny afternoon:

Look for insects congregating on the south and west walls (common for boxelder & stink bugs).

Inspect:

Window/door frames

Siding gaps

Roofline, soffits, fascia

Utility penetrations

Foundation cracks

Attic vents (install fine mesh if needed)

Interior Checklist

Check for gaps around:

Outlets & switches

Baseboards

Light fixtures

Attic access points

Window pulley openings (older homes)

Use caulk, weatherstripping, and expanding foam (sparingly) to seal.

I hope this helps!

Thank you so much for such a complete reply! I have two more things...

1. Does the cooperative extension service ever have someone come out to the house to solve these kinds of things. I'm a 70 year old woman with health issues who lives alone and it feels a bit overwhelming to me.

2. Here are some pictures of the TINY black bugs flying around. Does that help identify them any further? Pics are of some caught on a blue light trap. Also, they have an eratic, jerky flight pattern.

Hello again, Lynda

Your Question #1 - The cooperative extension service (MSUE) would not have someone come out to the house to solve these kinds of things. You would have to hire an exterminator to handle this kind of thing.

Your Question #2 – I identified the bugs as 2 Midges and a March fly 

I recommend you email all your images to the MSU Plant & Pest Diagnostics Lab for confirmation of identification.

ALSO, include in your e-mail - Pics are of some caught on a blue light trap. Also, they have an erratic, jerky flight pattern.

Their email is <personal data hidden> - Please include your first and last name.

The experts there can also provide you with the best treatment options.

The lab will let you know if they need a sample sent.

The lab may also ask for additional images. So be prepared. 

Their website is at this link:

Plant & Pest Diagnostics (msu.edu)

Their Contact Information is at this link:

Contact Us - Plant & Pest Diagnostics (msu.edu)

This link will explain the details on submitting a sample to the MSU Plant & Pest Diagnostics Lab:

Submit Samples - Plant & Pest Diagnostics (msu.edu)

I hope this helps!