Cluster flies can enter your homes through the smallest cracks around door and window frames or through any other tiny unsealed opening. A heavy infestation can result in thousands of flies, clustering together, earning them their name. Cluster flies are 8mm long and are a dark grey colour.

These pests can bring bacteria and disease into businesses and homes, which is why they should be treated at the earliest possible sight, or ideally, prevented before they can even get into the building.