What do you use for fly spray on your horse? I have been using 10% permethrin (2 oz) in a spray bottle with water. Is there some special mix that you swear by? Permethrin breaks down with sun and heat as I understand it so not sure it's even good after one summer. A bottle makes several gallons of spray when diluted with water but I'm not sure its still effective the second year. Maybe I need to store it in the fridge in the garage?
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