Fly

Black Blow Fly

Phormia regina

Moderate Risk

Biology

Phormia regina is a robust 8–11 mm fly with a dark metallic blue-black body and orange setae at the base of the wings. It develops on carrion and completes a generation in one to three weeks in cool weather.

Behaviour

Adults are strong fliers drawn to carrion, garbage, and wound tissue, and are active earlier and later in the season than other blow flies. Larvae feed in dense masses in decaying animal matter.

Habits

Sudden indoor swarms of sluggish shiny flies at windows usually mean a dead rodent or bird in a wall void, attic, or chimney. Adults mechanically carry bacteria onto food surfaces.

Control methods

1Locate and remove the carcass causing the breeding source
2Disinfect and deodorize the affected void after removal
3Screen chimneys, vents, and soffits to prevent animal entry
4Clean and seal refuse bins and dumpster pads
5Use a vacuum and light traps to clear remaining adults
6Seal wall and attic gaps used by rodents and birds

Tailored to Black Blow Fly

IPM Procedure Checklist

View full procedure

Step 1

Inspection

Locate breeding sites: drains, decaying matter, moist organics
Use tape-over-drain tests and UV/light traps to confirm
Map dumpster, grease and floor-drain hot-spots

Step 2

Identification

Confirm Black Blow Fly (Phormia regina) — not a look-alike
Note life stage and risk level: Moderate
Capture clear photos and samples for the record

Step 3

Action Thresholds

Trigger action when monitor counts trend up
Re-evaluate weekly during active season
Document trigger criteria in the IPM plan

Step 4

Prevention

Clean drains with enzymatic foam to remove biofilm
Manage trash, recycling and grease daily
Screen windows, doors and air curtains at entries

Step 5

Control Methods

Locate and remove the carcass causing the breeding source
Disinfect and deodorize the affected void after removal
Screen chimneys, vents, and soffits to prevent animal entry
Clean and seal refuse bins and dumpster pads

Step 6

Monitoring & Evaluation

Service monitors on schedule and trend captures
Re-inspect for Black Blow Fly activity at follow-up
Adjust tactics based on data; report findings to client