Endure doesn't work for me this year (worked last one though). That expensive Marygold (natural, "#1 rating") doesn't seem to be working either. Vinegar in food didn't change anything as well (was given it for several weeks). :) So I wipe on some Horse&Pony, which somewhat works... But looks like NOTHING helps with those big flies... :(
Endure is great for deer flies, not so great for horseflies, and does nothing for mosquitoes and fleas.
But deerflies are the big problem this month, so that's what I'm using. I used to think that nothing really worked, then I started to really get him wet with it and wipe it in to his coat--and presto it worked!
I use the spot on Celebration. This says to only apply every 14 days so I use the Ultra shield spray when I feel it wearing off and not time to reapply. And I feed the vinegar. Flies are not horrible but major mosquito issues here.
Ultra shiled $14 ( I try to buy the value bottles up when I see them with the extra 25% for free)