What are these giant green headed monsters that are always attacking me and my horse?

They are green heads.  A totally creative and appropriate name for these buggers.  And super tricky to manage - if you can at all. Here’s the thing about green head flies - they are not like normal flies at the barn that you can easily manage.  They are very similar to horse flies, which live everywhere! For several reasons:





  • Green head flies are larger than the typical barn fly.  They are a member of the horse fly family, but not as large as some other horse flies.  The green heads I have seen are just shy of an inch.  


  • Their bite HURTS.  Unlike some bugs that prick you and drink without you noticing, the green head fly slices the skin, waits for the blood to pool, then drinks from the puddle.  Super gross. 


  • Only the females bite, they need the protein in blood to carry on egg laying duties. 


  • They are attracted to movement and hunt via sight.  Not smell.  The usual bug sprays and fly sprays don’t even make a dent.  


  • They mainly feed on large dark creatures, like cattle and deer.  Horses and human will do as a food source when necessary.



No creature is safe.  The sawing action of the green head fly creates a lovely stream of blood to drink from.  Fly boots are a good idea here. 


  • Most of the US is safe from the green head.  They live in coastal marshy areas, typically on the north east coast.  


  • They can (and will) bite through your clothing.  Oh joy. 


  • Wind and fans are the green head's arch nemesis.  Savor a windy day and buy a boatload of fans when the wind isn't cooperating. 


What can you do for your horses?




  • Fly sheets with neck pieces are a good idea.  Same goes for fly masks.  Which, most of us use anyway.  I prefer light or white colored fly sheets anyway, which works well as the green head flies prefer dark colors.  


  • Let your horse have his tail.  I know we love our tail bags, but sometimes you just gotta let that tail fly free!


  • Use fans, even on the cooler days.  Many horses are on a night turn out plan during summer anyway, when the flies are not so active.  During the day, the fans and wind keep them at bay. 


  • You may be able to buy or make a green head fly trap.  Lots of plans and designs available with a quick internet search. 


  • Talk to your local agriculture extension service about the green heads in your area.  You may be able to get some solutions there!


How do you deal with these annoying flies?