What will keep the Cluster Flies away?

Cluster flies become a nuisance in residential and commercial properties, primarily during the fall and winter. They seek shelter in large numbers in warm, undisturbed areas like attics or wall voids to overwinter. Their presence can be overwhelming, and although they don’t breed indoors or spread diseases, they can stain surfaces and create an unpleasant odour. Addressing cluster fly infestations is essential to maintain a clean, comfortable living or working environment.

Identifying a cluster fly infestation involves looking for several signs. These flies are often seen in large numbers around windows or in attic spaces, especially on sunny, warm days during fall and winter. Their sluggish behaviour and characteristic buzzing are also indicative. Additionally, finding dead flies in light fixtures or window sills and dark, non-glossy flies with golden hairs are key identifiers.

Natural remedies, such as essential oils (e.g., eucalyptus, lavender, or peppermint oil), can act as deterrents but are usually less effective than professional treatments. Light traps and sticky traps can also be used to capture flies. However, for large infestations, these methods may not be sufficient, and professional intervention might be necessary.

Cluster flies can return after treatment, especially if the underlying conditions that attract them remain unchanged. These flies are known for their tendency to return to the exact locations year after year for overwintering. To prevent reinfestation, it’s essential to maintain preventive measures like sealing entry points, using light and sticky traps, and considering annual professional treatments before the onset of colder weather.

The life cycle of cluster flies consists of four stages: egg, larva, pupa, and adult. Eggs are laid in the soil and hatch into larvae, parasitizing earthworms. After several larval stages, they pupate in the ground. The entire cycle from egg to adult can take 27-39 days, depending on temperature and environmental conditions. This lifecycle knowledge is critical for timing control measures.

Cluster flies are not harmful to humans or pets. They do not bite, spread diseases, or infest food supplies. However, their presence in large numbers can be distressing, and their droppings may stain fabrics and surfaces. While not a health hazard, their infestation can impact the comfort and aesthetic of a property.