NPIPM:Musca domestica Linnaeus
Authors: Ashley Mueller, Buyung Hadi
Flies are one of the most recognizable pests in the home. While they can be a nuisance, some species are a cause for health concern. These medically important flies are capable of transmitting bacteria and other disease-producing organisms that can affect the human digestive system.
Flies undergo four developmental stages: egg, larval, pupal, and adult. Flies are attracted to decaying organic materials. Places in the home where they are likely to reside are near room-temperature ripened produce and seldom-used drains and sinks. Adult flies are primarily active during the day, so they are often noticed. Preventing and managing flies indoors requires proper food storage and good sanitation practices in the kitchen and regular cleaning of areas that could be optimal breeding sites.
Identification
Adult house flies (Musca domestica Linnaeus) are 6 to 7 mm long. Females tend to be larger and have a relatively wide space between the eyes compared to males. House fly eyes are red in color, and the mouthparts are the sponging type. Their abdomens are gray or yellow with irregular dark markings on the side. House flies are commonly found in places where there is human activity as well as on ranches, horse stables, and livestock operations.
Habitat
The house fly is found in all climates, and it is common in both rural and urban environments. It is typically associated with animal feces, but it also attracted to human food and garbage, so it can be found anywhere people live.
Life Cycle and Seasonal History
The house fly develops in four stages: egg, larva, pupal, and adult. Adult females lay eggs singly but in small piles in a nutrient-rich, moist location. They can lay as many as 500 eggs over a three to four day period, and several flies will deposit eggs in close proximity. Legless larvae, also called maggots, emerge within eight to 20 hours. Upon emerging, the white maggots, about 3 to 9 mm long, feed immediately on the material in which the eggs were laid. Larvae go through three instars or development stages before becoming full-grown maggots. Maggots find a cool, dry place to pupate. A pupal case is formed, and it changes in color from yellow to black as it ages. In two to six days, pupae develop and emerge as adults.
Adults live 15 to 25 days, and in some cases, up to two months. Without food, adults are only able to survive a couple of days. The optimum time for development is the summer, and the life cycle is complete in seven to 10 days. Annually, 10 to 12 generations may occur. House flies overwinter in the larval or pupal stage in protected areas.
Human Interaction and Urban Impact
Although not an economically important pest, house flies are a cause for health concern because they can transport diseases to humans. These flies can pick up pathogenic organisms—such as bacteria, viruses, fungi, protozoa, and nematodes—from garbage and sewage and transfer them to human and animal food through touch, regurgitation, and their feces. Pathogens commonly transmitted by house flies are Escherichia, Salmonella, Campylobacter, Shigella, and Clamydia. Adult house flies can also be a nuisance, bothering humans and animals if the population gets too large, but they do not bite.
Prevention and Management Approaches
To prevent house flies from going indoors, make sure windows and doors are well-sealed and screens are functioning properly. Trash should be placed in plastic bags, and trash cans and dumpsters should have lids. Eliminating potential breeding sites, like food and other moist materials, is key in the prevention of a house fly infestation. Good sanitation is always important in managing flies. When serving food in areas with a high house fly populations, such as picnics outdoors, use screened lids to keep flies from landing on the food. Keep tables and cooking surfaces clean and free of debris.
In most cases, flies that are found in a building have entered from outdoors. Organic waste, such as rotting fruit and pet feces, should be removed weekly to reduce house flies attracted to the area. Do not store garbage near the entrance to the building. In the home, the use of fly swatters can be quite effective in eradicating house flies. Use care with a fly swatter near food and on food preparation areas. Fly traps and fly paper may also be effective in managing house flies. With disinfectant, be sure to wipe the area where fly swatter contact with the fly was made. Sticky fly ribbons or papers are good for managing a small amount of flies in a small area. In most residential situations, the use of pesticides to manage house flies is not recommended.
Other Online Resources
University of California, Davis
For information regarding labels of chemical control options, please visit NPIC MAPL
