I have used kerosene soaked rags tied around my ankles, worked ok, but you have to be careful if you smoke
Kerosene also seems to help after you've been bitten. I guess it kills them or something. I've also had good results using laquer thinner or acetone(fingernail polish remover) on chigger bites. None of the above are very healthy to use on your skin, but when you're ate up with red bugs, who cares.