Yesterday's XKCD seems appropriate: http://xkcd.com/1702/

I live in a place with the triple threat of chiggers, skeeters, and ticks. It's usually a bad idea to do much backpacking during the summer because each of the three are terrible on their own. I use OFF Deep Woods, which if I remember right is 25% DEET. I'd love to find an alternative, though, because I don't like the smell and I don't like the melted plastic. I generally just spray my clothing down and avoid getting it on my skin if possible.

At the summer camp I work at every summer, chiggers are the big threat. We use unscented dryer sheets in our shoes and beds to keep them off. Works like a charm, and helps with skeeters and chiggers, too -- though not as much as DEET. You need a fresh one each day, and if you sweat all over it, you need a fresh one sooner. So the weight could get to be too much for backpacking. Still, it's an idea. Application is to rub down your legs with the sheet and then tie it into your shoe laces, or if going into your bed, put it between the mattress and fitted sheet. I like to put one on each side of my pillow, under the case, as well.