Lucilia sericata, formerly known as Phaenicia sericata, is one of the most prevalent blowfly species in the world, and it’s also a common pest of homes and buildings in the US, especially in the north where they are particularly abundant in urban and suburban areas. This species is often referred to as the common green bottle fly due to its metallic green exterior, which can often be seen by the naked eye despite this species’ small size and close resemblance to common houseflies. Adult green bottle flies are slightly less than one centimeter in length with translucent wings and their eyes are large and red in color. Like house flies, fruit flies, drain flies, and all Dipteran filth fly species, green bottle flies congregate on microbe-rich forms of organic waste for the purpose of mating and egg-laying.

While fruit flies prefer to lay eggs on overripe fruits, and house flies prefer to lay eggs on rotting food and other decomposing materials in garbage piles, green bottle flies prefer to lay eggs on rotting carcasses. Because of this, the green bottle fly is important in the field of forensic entomology, but green bottle flies also favor human and animal excrement, meats, and occasionally, rotting vegetable matter as breeding substrates. Due to their preference for breeding on organic waste materials that are particularly rich in disease-causing microorganisms, as well as their habit of laying eggs on meat and fish, green bottle flies pose a greater disease threat within homes than houseflies. Unfortunately, a recent nationwide survey revealed that green bottle flies are one of the ten most commonly controlled fly pests within residential areas.

Unlike most blowfly species, L. sericata readily enter homes in Massachusetts where they may establish a reproductive population if they locate a suitable source of organic waste for their larval offspring to consume upon hatching. Within and around homes, this species lays eggs on pet excrement, compost, dead rodents in attics and wall voids, rotting food in sinks and garbage cans, and even meat and fish meant for human consumption. Consuming meat contaminated with green bottle fly eggs will likely result in a serious case of food-borne illness, but thoroughly cooking meat will destroy eggs. Green bottle fly larvae (maggots) have been spotted crawling about within heavily infested homes, and infestations can usually be avoided with good sanitation practices.

Have you ever found fly larvae in your home?