I am guessing you are worried about ticks.
Some non chemical tips.
Wear longer tube socks and tuck your pants legs into the sock.
Wear long sleeved T shirts and keep every thing tucked in.
Light colored clothing helps spot ticks quicker.
Ticks don't cling well to those smooth green rubber boots.
If you have been in the woods for a day - remove all clothing, empty pockets and put in a cloths dryer at a hot setting for 10 minutes or more.
Never lay your outdoor clothes on your bedding. Keep them as far away from where you sleep as you can.
JW