Cluster Flies

Cluster Flies

When autumn arrives, you could see clusters of flies swarming over your house. During the winter, these pests seek refuge and warmth in their homes. Cluster flies emerge as the weather warms up in the spring. Cluster flies are a pest that may spend the winter in your house, so we've compiled some information to assist you in keeping them out. Cluster flies are dark grey in color and are around 1/3" to 2/5" in length. Their bodies are covered in golden hairs, with a distinctly bright and dark checkered pattern running down their abdomens. A striped pattern may also be seen behind their heads. Like other fly species, they have two big eyes. Cluster fly larvae have the appearance of little white worms.


Blowflies and cluster flies are in the same family. They prefer to reside near the earth while they are outside. They're also known as grass flies. Adults eat nectar from flowers, plant sap, fruits, and other organic matter. Their larvae are earthworm parasites. Female cluster flies usually lay their eggs beside  earthworm tunnels in the dirt. The larvae can then dig into the earth and eat the worms. Cluster flies are drawn to light, which explains why they are drawn to windows on bright days. They are also drawn to artificial sources of light. Unlike many other varieties of filthy flies, these flies are not drawn to rubbish and other refuse.


Cluster flies are drawn to the highest portions of your home, such as the attic, when they come inside. This is why they are also known as attic flies. Cracks, fissures, and voids are where they hide. Cluster flies can be discovered hiding behind curtains, inside clothing, in closets, behind picture frames, and under furniture in your house. They remain in close proximity to people.


Cluster flies are annoying overwintering pests, although they do not bite humans or animals (excluding earthworms), do not carry bacteria, and do not lay eggs in the food. They do not have any serious health risks. Because of the extent of the infestation, cluster flies are an issue. Infestations can get huge because they cluster together.


Cluster fly prevention mostly entails closing holes and crevices in your home's walls and foundation so that the flies don't have access to warm hiding spots. Cluster flies are most likely to enter a structure from the west and south sides. Make sure gaps around external vents, rooflines, water spigots, and other pipe entrances, and foundation sill plates are all sealed.

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