It worked really well on my lot when they got lice ( maybe also mites) this winter. No problems since.
Really smelly nasty stuff that you have to wear protective gear for. I used a spray from my garden centre that gave a fine mist, enabling me to cover the whole horse with the prescribed amount, and a sponge for the head etc.
Apply every two weeks. But make sure it doesn't go on any broken skin - horses will tell you it stings. It works best on crawling insects as it does not deter flies from landing on the skin. It works on the insects nervous system, so they die when they absorb it. So stops insects biting but does not stop them annoying the horse. One of the better fly-sprays (can't remember which one) combines the same active ingredient with a fly repellent, but of course its a lot more expensive.
I use it as a fly spray, don't normally wear gloves.
I dilute it and spray the horse liberally (except for his head) and then 'wipe it in' with a cloth or a sponge. Finally use the damp cloth to do his head.
Normally only have to apply it every 2-3 days unless it rains.
brilliant. The only thing I use for both Lice and Fly Protection. Works extremely well an actually works out cheap due to dilution rate and length of activity. For fly protection I have never needed to apply more than every four weeks, sometimes longer.
Yes its great for lice. But don't leave it in a plastic spray bottle as it wrecks the sprayer very quickly. Used it a couple of times as a fly spray but didn't seem any better than any other one to me. Also, I wasn't too keen on using it with the regularity of a fly spray as it is pretty nasty stuff.