There are several species of green bottle fly. Two of the more common ones are Lucilia illustris (Meigen) and Phaenicia sericata (Meigen). They are found throughout the United States.
Green bottle flies are larger than houseflies. They are almost 0.5″ long. The abdomen and mid-section are shiny and green.
Homeowners usually notice green bottle flies when they are buzzing at a window during the day. They seem to buzz loudly all day without getting tired. These flies can be more than nuisances, however. They can transport disease organisms on their legs and bodies. If they walk on food or food surfaces, they can easily contaminate them.
Green bottle flies deposit their eggs in decaying material. They often find rats or mice that have been poisoned or left in traps. They may find a dead bird in a rain gutter or a squirrel in the attic. They also deposit their eggs in garbage cans and animal droppings.
The female fly can deposit more than 2,000 eggs. The larvae, or maggots, feed on the decaying material where they hatch. When they are ready to change to adult flies, homeowners often find the maggots moving around.
If there are a few flies inside the house, they might come inside from an infestation outside. However, if there are a large number of flies indoors, it could mean that there is a dead mouse or bird in the attic or inside of a wall.
Solving a green bottle fly problem begins with an inspection. Finding the breeding site is thee critical step. If there is an animal carcass, it should not be handled barehanded. A trash bag can be inverted over the carcass and used to remove it. A vacuum cleaner is an efficient way to remove maggots inside the house. It will also remove the buzzing flies at the windows.
After the carcass has been removed, it may be necessary to apply aerosol or dust insecticide for fleas, bed bugs, beetles, or scavenging insects. Many homeowners call on a pest control professional for help with green bottle flies. These people can make the inspection and make any insecticide applications that are needed.