When out for Sept. dove in TX its still chigger season and they will cross a trap to get to me. Single most important item to keep them at bay is an old sock filled with a handful of dusting sulfur & tied off. Keep it in a pound coffee can w/lid when not in use. Just bang it against yer boots, pants and around yer waist and they mostly stay off. A bottle of clear fingernail polish will suffocate the ones that bite you anyway, but that's post hunt therapy.
Another couple or three items worth packing are extra ear plugs and glasses for those invariably not having them. FWIW, I've found the clear poly glasses sold at most sporty stores & the Wally Marts for 'air soft' use have the highest protective impact ratings and they are inexpensive. Always pack at least a roll of paper towels.
I've also seen times when having some Zantac for the over exuberant and Immodium for the unfortunate was most appreciated.