How Do Cluster Flies Enter Buildings?

Weather and seasonal changes significantly affect cluster fly activity. They are most active in late summer and early fall when they seek shelter for overwintering. Warm, sunny days during winter can also stimulate activity within buildings. Understanding these patterns helps in timing prevention and control efforts effectively.

To prevent cluster flies from returning, there are several steps you can take. Seal any openings or cracks in windows, doors, and screens to prevent their entry. Install properly fitted screens on windows, vents, and chimneys. Apply residual insecticides or dusts around the exterior of your home, particularly in areas where cluster flies congregate. Vacuum and remove cluster flies indoors, and use sticky traps or fly traps near windows. Manage exterior lighting to reduce attraction. Maintain cleanliness and sanitation inside your home, and consider seeking professional pest control assistance if needed. By implementing these measures, you can help prevent cluster flies from returning and minimize their presence in your living space.

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 become most active during the late summer and early fall. This is when they seek shelter in homes and buildings for overwintering. However, you might also notice increased activity on warm, sunny days in the winter and early spring as the flies become more active due to the warmth.

Cluster flies themselves do not cause physical property damage. However, their droppings can stain fabrics and surfaces, and large numbers of dead flies can create a mess and an unpleasant odour. The primary concern with cluster flies is more about nuisance and maintaining a clean environment than physical property damage.

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.