Several species of blow flies are common pests throughout the US, and their habit of congregating onto pathogen rich decaying materials, most notably animal carcasses, makes the pests capable of spreading diseases to humans. Numerous flies congregate on filthy materials, like garbage, feces and rotting food, for feeding and reproductive purposes. Flies lay eggs in decaying organic materials in order to provide developing larvae with a nourishing environment upon hatching. Blow flies prefer to feed and lay eggs on decaying animal bodies, and they congregate in landfills, dumpsters and residential garbage bins for the same purpose.

Unfortunately, several blow fly species are known for infesting homes, especially homes located near slaughterhouses, meat processing plants and landfills. Two groups of blow fly pests, greenbottle and bluebottle flies, freely invade homes regularly no matter the location, as they are able to disperse over unusually long distances compared to other fly pests. The most common blow fly house pest in Louisiana, Phaenicia (Lucilia) sericata, breeds and feeds on dead mice, rats and other animal carcasses in wall voids, crawl spaces, attics, behind appliances and storage areas. This species is frequently referred to as the common green bottle fly, and it establishes infestations within homes more often than house flies.

In addition to animal carcasses, the common green bottle fly feeds and lays eggs on indoor food sources, such as meats, fruits, and vegetables. This causes food within infested homes to become smeared with a variety of disease-causing microorganisms, making blow flies among the most dangerous of indoor insect pests. Keeping meat and fish away from blow flies is particularly important, as eggs and larvae are most numerous on these foods. Eating food containing blow fly eggs and larvae will cause serious gastric and enteric illness, such as E. coli, rotavirus and shigella. Blow flies are larger than house flies and they can be recognized for their metallic green-colored bodies, fast flying speed, and loud buzzing.

Have you ever eaten food despite seeing a fly crawling on it?