Thanks Lloyd. I've been using Picardin instead of DEET for the last few years and find it works well. Does that brand really have zero scent? The brand I use has a distinctive scent when first applied.
I also learned something about Permethrin early this summer. I found a dog tick crawling in my dogs ear, and plucked it out. I decided to test my 0.5% mix of Martin's Permethrin on it, so ran inside and grabbed my pre-mixed spray bottle. I sprayed a shot onto the hood of my tractor and dropped the tick into the middle of the moistened area, expecting a quick end. The little bastard kept crawling out of it, several times.
I had tried this sort of experiment once before on a freshly pre-treated pair of work pants, and the tick began acting funny before it moved a foot. Then it began moving in small circles for a short time and then curled up and died. I was impressed to say the least. But this particular dog tick seemed almost immune to my Permethrin. I dunked a small twig into the solution and put a drop directly on the tick. He kept moving normally for a couple minutes before finally slowing down. Five minutes or so later, he was clearly affected, but his legs were still moving, and it took several more minutes before he died.
I was quite concerned that this tick was able to live so long with direct exposure to my Permethrin solution, which had been carefully mixed at 1 part Martin's 10% Permethrin and 19 parts water. The tick was literally bathed in it, and I had expected it to die within seconds. I suddenly wasn't so confident about my pre-treated clothing and boots protecting me, so I went online to search for a possible reason, such as Permethrin losing potency after a few years, etc.
What I learned was that Permethrin concentrate will settle in the bottle, so it should be shaken well before measuring and mixing with water. I'm sure I didn't shake mine the last time I made up a couple spray bottles of 0.5% mix. Also, it doesn't seem to create any danger for humans to bump up the concentration to .75% for treating clothing, shoes, etc. Diluted Permethrin is routinely sprayed directly onto dogs and livestock without causing any ill effects.