Q: What can I use in my fogger to control flies in my horse barn? I have tempo and seven on hand.
A: First, check to see if there are screens on barn entryways (i.e., windows and doors). If so, then try to keep horses inside when flies and mosquitoes are most active. Avoidance is always a good strategy, provided indoors is not the source of flies, especially stable flies.
Remember, fogging indoors will be temporary at best, and futile if flies can get inside from outdoor sources. Second, make sure manure is properly disposed on, including both indoor and outdoor disposal of feces, urine-soaked bedding, and any feed source wet enough to support fly breeding. A dry environment is good, and will limit on-site production of biting stable flies and nuisance house flies.
Hand-held misters or foggers are really designed to create a fog of a short-lived, contact insecticide such as the botanicals pyrethrins. Little droplets hit the flies directly, and they are killed as the toxin enters their bodies and disrupts their nervous systems. Pyrethrins are likely to be formulated with various synergists to enhance efficacy, and both are quite safe around animals, pets, and people. Pyrethrins are common and should be available from local tack shops or farm supply outlet. Seek products formulated for indoor use, and FOLLOW ALL INSTRUCTIONS on the container.
Tempo is one of the synthetic pyrethroids, and is meant to provide a longer acting (1-2 weeks) surface residue. Comparable products with other pyrethroids are also available. These can be applied as coarse water sprays to building and stall surfaces using a hand sprayer. Check the label to confirm, but I do not think Tempo is formulated for application with a hand mister/fogger. Sevin (carbaryl) is an organophosphate that is formulated for garden use, and I would be surprised if it is registered for premise applications against flies. Again, check the label to confirm.
Remember, the best way to reduce fly population is with cleanliness.
By Roger Moon, PhD, University of Minnesota
The information given is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by University of Minnesota Extension is implied.