Dust your lawn with sulphur - keep your grass cut low - if you have bermuda grass, try to replace it with bug free St. Augustine. Also, make Avon's Skin-so-soft body oil part of your routine during the summer months. My husband attracts the little devils as though he is oozing honey but if he wipes his legs down with Skin-so-soft, he never gets a bite. The sulphur is an old-time southern solution and works great unless you are allergic to sulphur. We actually swallowed sulphur tablets when I was a child.
Even now, I can walk through a pasture with johnson grass up to my waist and never get a chigger. If you are infested, take a vinegar bath to get rid of them.