I've got mine covered in Deosect and it seems to be stopping the feckers landing on the ponies but not stopping them buzzing around them. My own mix of baby lotion, tea tree oil, lavender oil and eucalyptus oil slathered on undercarriages also seems to keep them away for a few hours
The only way to avoid them whilst riding is to get out before they get out of bed! Was out at 7 this morning for an hour and a half and not one in sight, helped by a bit of breeze. Once they come out to play, they seem to stick around until at least 7pm.
I'm sure the damn things hang around until I've left the yard. You can almost hear them saying, 'You gonna ride her now eh,eh ?'
Nothings works on my black mare, although mosquito repellent is pretty good.
I have had some success in waving a leafy branch around her head as we ride, in an Egyptian slave style. She likes that, but I'm not so keen. I think I do enough to ensure madam's comfort already.
Have heard the old fashioned method was to tie bracken to the bridle to keep away the beggars...did try it out on a hack when i remembered...my horse wasn't impressed with having his browband fiddled and stabbed with 'foliage' whilst riding but it did seem to work! Now to work out how to make a rug out of bracken