Bottle Fly

What do Green, Blue blow, and Bottle Flies look like?

  • Despite their fascinating metallic appearance including black blowflies – dark metallic green; green bottle flies – metallic blue-green; and bluebottle flies – metallic blue, you don’t want these flies landing on you.  
  • Larvae (maggots) are cream-colored.
  • Fly size is 1/4 inch for the black blowfly and more than 1/2 inch for the bluebottle flies while mature larvae (maggots) are 3/8 to 7/8 inch long.
  • Flies have “sponging” mouthparts.
  • Larvae (maggots) are “legless and eyeless,” and taper from the larger round rear segment to the pointed head—which consists of a pair of “mouth hooks.”
  • Larvae have large spiracles (breathing mechanisms) on their posterior plate.

What are the habits of green, blue blow, and bottle flies? 

  • The females lay from 540-2,373 eggs in their lifetime!
  • After seeking out suitable organic matter sites, eggs are laid in batches of 100 to 180 on meat, fish, or carrion (while blowflies are also attracted to animal manure, feces, garbage, and rotting vegetable matter).
  • Larva and pupa stages are considered overwintering stages—meaning that they can ride out winter before emerging following this process.
  • Development from egg to adult is as short as 10 days but may be 15 to 20 days.
  • Blowflies are often found inside the decaying bodies of rodents and other dead animals within attics, wall voids, and chimneys.
  • Some species are strong fliers and are attracted to bright light (including fly-lights). 

What kind of damage is caused by green, blue blow, and bottle flies?  

  • Blowflies are rarely a significant problem within structures but can be quite annoying because of their persistent buzzing and intimidation. 
  • The major health concern associated with blowflies is their ability to carry disease-causing organisms on their bodies—and transfer to other items (such as food) as a function of landing and mechanical transfer. 
  • Uncontrolled infestations can cause economic damage to restaurants, bars, and commercial hospitality establishments as a result of health inspections that may result in closures if/when abundant populations are observed.  

What should I look for?

  • When identifying green, blue blow, and bottle flies, look for their most obvious physical characteristic—their shiny metallic color.  
  • Sometimes, fly-specks (small black fecal deposits) can be found.
  • Look for larvae leaving the breeding sites or breeding medium in order to pupate.
  • Search for decaying organic matter or dead animals (that may serve as the host).

How do I control and kill green, blue blow, and bottle flies?  

  • Sanitation and source-remediation is the most effective step in blowfly control because larval breeding sites are eliminated.
  • Trash cans (exterior or food service facility), recycling, and compost containers should be cleaned at least weekly in order in order to disrupt the developmental cycle.
  • In areas such that accumulate animal waste such as stables, barns, food processing plants, pet kennels, and poultry houses, animal feces should be spread out in order to allow for drying—which will eliminate the suitability for larval development.  
  • Insect-proof garbage containers, screens, automatic doors, and caulking to exclude flies can be employed.
  • Green, blue blow and bottle flies are highly receptive and attracted to electric fly traps, sticky pheromone traps, and other devices and should be used to reduce adult fly populations.
  • Aerosolized insecticides such as PI can be used to knock-down adult populations; however, this process will not interrupt the breeding site if the host is not located and removed. 


At Innotech Pest Management, we know that dealing with the green, blue blow, and bottle flies is a messy job.  If you need assistance identifying, analyzing, and treating these infestations, contact our team to schedule an evaluation and estimate to resolve your problems.