There are a number of tick borne diseases that your dog can contract. Keeping your yard as tick free as possible can help.
If you drag a white sheet across your yard, if you have ticks they will stick to the sheet. You then put the sheet in the dryer for 10 minutes to kill the ticks.
This is a good way to check your yard.
You can hire a company to treat your property with all natural products.
For those of you that do not like to use topical preventions that you get from your vet; here are a few natural methods.
Garlic – Bug Off Garlic – www.springtimeinc.com
Brewers yeast http://www.vetinfo.com/natural-tick-prevention.html/
Apple cider vinegar http://www.vetinfo.com/natural-tick-prevention.html/
Diatomaceous earth http://www.lowchensaustralia.com/health/diatearth.htm
I have read that garlic and brewers yeast given in too high a dose can be harmful or deadly to your dog so be sure and do your research and check with your vet.