Cluster flies on ranch

We have a cluster fly infestation on our ranch near Williams Lake B.C. Is Dragnet FT EC the best insecticide to use? If not what would you recommend ? Regards, GWN

Dragnet can only be purchased and applied by a licensed pest professional.  
To eliminate cluster flies, your should first understand their life cycle.  They breed outdoors in the summer and hibernate indoors in the winter.  Blocking off the entry points is the best solution but it can be very difficult caulking all the cracks and crevices around a building.  A pest professional could fog an attic in the fall but it may take more than one treatment and may not solve the problem. Read more about cluster flies:  http://pestcontrolcanada.com/flies/cluster-flies