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Blow Fly — species photo
Daniel Brady · NH-Licensed Pesticide Applicator · License #782664

How to Get Rid of Blow Flies

Doable with care
To get rid of blow flies, find and remove the dead animal they're breeding on — this is almost always the cause of a sudden indoor burst of shiny blue or green flies. Follow the odor and the flies themselves to locate the carcass, which is often a rodent in a wall void, attic, chimney, or crawlspace. Double-bag and dispose of it, then disinfect the area and vacuum up any remaining maggots or dead flies. Spraying the adult flies you see does nothing about the ones still developing on the carcass, so it's not a fix by itself. If the carcass is somewhere you can't safely reach — deep in a wall or on a high roofline — that's when a pest professional becomes the practical choice, not because the flies are dangerous, but because the source is out of DIY reach.

At a glance

  • Difficulty: Intermediate
  • Time: A few hours to locate and remove the source, longer if access is limited
  • Cost: Low — gloves, bags, disinfectant
  • Success: High once the carcass is found and removed; low from spraying alone
The honest answer

Can you DIY Blow Fly?

The verdict on Blow Fly DIY

Doable with careIntermediate

Solvable DIY if you can find the carcass — a wall void or high roofline is where it gets hard.

Blow flies — the shiny metallic blue or green flies that suddenly appear indoors in numbers — almost always mean a dead animal, often a rodent, is decomposing somewhere in the house. "Follow your nose" is the actual method: locate and remove the carcass, double-bag it, and disinfect the area. A homeowner who can access the source (an attic, a crawlspace, an accessible wall panel) can usually handle this. When the carcass is in a wall void or a high roofline you can't safely reach, that's a practical reason to call a pro, not a health emergency.

The playbook

The 5 DIY methods — honestly graded

Every approach graded for this species, in IPM order — prevention first, chemistry late. Pick a method to see how it works, the steps, and what it actually takes.

Prevention / Exclusion

Works well

Removing the carcass is the entire fix — everything else is cleanup.

Blow flies are drawn to and breed on decomposing animal tissue. Finding and removing that carcass eliminates the food and egg-laying site the flies depend on.

Best for: Every case — this is the method that actually solves it

  1. Follow the flies and the odor

    Track where flies cluster and where the smell is strongest — attics, chimneys, crawlspaces, and wall voids near where rodents commonly enter are the usual spots.

    Caution
    Wear gloves and an N95 mask before handling a carcass; some diseases can spread from rodent remains.

  2. Remove, bag, and disinfect

    Double-bag the carcass and dispose of it in outdoor trash. Disinfect the area where it was found.

  3. Exclude and screen

    Once the carcass is gone, seal the rodent entry point that let the animal in, and screen windows and doors to keep new adult flies out.

Tools & materials

GlovesN95 maskHeavy-duty trash bagsDisinfectant
Before you start
If the carcass is in a wall void or high roofline you can't safely access, don't force it — call a pro instead.
Reality check

Why DIY falls short here

Not scare tactics — the specific, proportionate reasons a home attempt can stall for this species.

Can't find or reach the carcass

A wall void or a high roofline can make source removal impractical for a homeowner — that's a practicality reason to call a pro, not a health emergency.

Spraying without removing the source

Adults keep emerging from the carcass until it's gone; a spray only knocks down what's already flying.

Straight talk

How risky is it, really?

An honest read — most nuisance species are genuinely low risk, and we say so.

Low risk

Blow flies and their maggots are essentially harmless to people. Like houseflies, they can mechanically carry bacteria from the carcass to nearby surfaces, but the main issue is the odor and nuisance of a decomposing animal, not disease.

  • Odor and nuisance from the carcassCommon

    The primary complaint — resolves once the carcass is removed

    Iowa State University Extension

  • Mechanical pathogen transfer from filth to surfacesOccasional

    Contamination risk, not a biting or feeding risk

    Bug Out Service (pest industry)

When to call a pro

A Dead-Animal Fly Problem You Can't Reach?

When the carcass is behind a wall or high on a roofline, DIY access runs out. Anchor Pest Services locates hidden sources and handles rodent exclusion across southern and central New Hampshire. Family-owned since 2017, NH license #782664.

Call a pro when…

  • The carcass appears to be in a wall void, attic space, or roofline you can't access
  • The odor persists after a thorough search and you can't locate the source
  • Repeated rodent entry keeps bringing new carcasses into the structure

General Pest Control

Call a pro when the carcass is somewhere you can't safely or practically reach — deep in a wall void, a high roofline, or a chimney. It's about access, not danger: blow flies themselves pose low risk.

Get a Free inspection(603) 785-0118

Keep them out

  • Seal rodent entry points to prevent animals from dying inside walls or attics
  • Screen windows and doors to keep adult flies from entering
  • Address any dead-animal odor promptly before flies establish
New Hampshire context

Blow flies in New Hampshire homes

In NH, blow fly bursts indoors are most common in fall and winter, when mice and other rodents move into wall voids and attics seeking warmth and sometimes die there. A sudden cluster of shiny flies at a window in an otherwise fly-free house is the classic sign of a hidden carcass, not an open-door problem.

Peak season

Fall through winter, tied to rodent activity indoors

Before you treat

Make sure it's a Blow Fly

Two quick detours worth taking — confirm the ID, then learn what drew it in so it doesn't come back.

Not sure it's this?

Identify Blow Fly in the Pest Library

Why is it here?

What actually attracts Blow Fly

Common questions

Frequently asked

Sources & further reading(3)
  1. [1]
    Iowa State University Extension — Blow and Flesh Flies

    Carcass-source biology, risk, and control

    extensionverified 2026-07-13
  2. [2]
    Colonial Pest Control — Blow Flies and Carcasses

    Practical carcass-location and access guidance

    industryverified 2026-07-13
  3. [3]
    Bug Out Service — Blow Flies

    Mechanical pathogen transfer, nuisance framing

    industryverified 2026-07-13

Written & reviewed by

Verified

Daniel Brady

NH-Licensed Pesticide Applicator · License #782664 (NHDAMF, RSA 430)

Daniel Brady is the New Hampshire–licensed applicator behind Anchor Pest Services, a family-owned pest control company serving the Manchester area since 2017.

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Last updated July 2026

More in Flies & Gnats

Other species you can tackle

Same category — the dot shows each one's DIY verdict at a glance (green = friendly, amber = doable with care, red = call a pro).

Professional Pest Control

A Dead-Animal Fly Problem You Can't Reach?

When the carcass is behind a wall or high on a roofline, DIY access runs out. Anchor Pest Services locates hidden sources and handles rodent exclusion across southern and central New Hampshire. Family-owned since 2017, NH license #782664.

Get a Free inspection(603) 785-0118
  • NH-licensed applicators (#782664)
  • Free inspection — same-day service across southern NH

NH License #782664 · No obligation · We answer in person

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