🔧 HOW-TO

How to Stop Stink Bugs From Invading Your Home in Fall

September is the critical month for stink bug prevention. A perimeter spray before they aggregate stops thousands from entering.

⏱️ 2 hours 💪 Easy

🧰 What You'll Need

Bifenthrin sprayCaulk gunWindow screen patches

📋 Steps

1
Apply exterior perimeter spray in early September
Spray bifenthrin or lambda-cyhalothrin on all south and west-facing exterior walls from ground to 2nd-story eaves before stink bugs start aggregating. The spray must be applied before they arrive — not after they're already on the building.
2
Seal exterior gaps before spraying
Walk the exterior and caulk any visible gap — window frame perimeters, door frames, where siding meets foundation. Even gaps too small to see easily allow stink bugs. This exclusion work amplifies the spray effectiveness.
3
Repair damaged window screens
Stink bugs enter through damaged screens. Repair or replace any screen with holes before September. Pay attention to attic gable vents — these are major entry points.
4
Vacuum indoor stink bugs — never crush
If stink bugs make it inside, vacuum them up. Crushing releases the odor and can stain surfaces. Empty the vacuum immediately outside. A stink bug trapped inside a vacuum bag emits odor continuously.
5
Don't treat wall voids
Once stink bugs are in the wall, no spray treatment is effective or practical. Let them overwinter there and focus on sealing for next year.

💡 Pro Tips

  • A single September spray application provides 45-90 days of residual protection — timing is everything
  • South and west-facing walls receive maximum afternoon sun warmth that stink bugs seek — prioritize those walls
  • The same September spray also prevents Asian lady beetles, boxelder bugs, and cluster flies — it's the most cost-effective fall pest treatment

💰 Cost to Fix This Problem

ApproachTypical CostBest For
DIY materials only$25–$75Mild or early-stage infestations
Professional service (one-time)$150–$400Active infestations or when DIY has already failed
Ongoing service contract$400–$800/yrPrevention and long-term peace of mind

Costs vary by region, property size, and severity. Get at least two quotes before hiring.

✅ How to Know It's Working

Pest control success is measured in weeks, not days. Here's what to look for:

💡 Monitoring tip: Place sticky traps in corners and along walls before you start treatment. Counting catches weekly gives you objective data on whether the population is declining.

👷 When to Call a Professional

DIY is appropriate for small, contained infestations caught early. Call a licensed professional when:

⚠️ Rule of thumb: If you've spent more on DIY materials than a professional visit would cost, it's time to call.

❓ Frequently Asked Questions

Why are stink bugs invading my house in fall?
Brown marmorated stink bugs seek sheltered overwintering sites as temperatures drop below 50F. They are attracted to warm, sun-exposed walls and enter through gaps around windows and utility penetrations. They do not reproduce inside homes.
Should I vacuum stink bugs or spray them?
Vacuuming is best for those already inside. Use a dedicated vacuum or sealable bag since the odor persists. Spraying individual stink bugs is unnecessary. Do not crush them as the odor attracts more.
How do I prevent stink bugs from entering next fall?
Seal all entry points in late August: caulk windows and door frames, install door sweeps, repair screens. Apply residual bifenthrin to exterior south and west-facing walls in mid-September before bugs begin landing.
Do stink bugs cause damage inside?
Stink bugs do not cause structural damage, bite, reproduce, or feed indoors. The primary nuisances are odor when disturbed, their presence in large numbers, and staining from their defensive secretion. They leave naturally in spring.
📚 Sources: EPA Safe Pest Control · NPMA Pest Guide
Published: Jan 1, 2025 · Updated: Apr 7, 2026