I use a product called flicks spray. It says it's for horses but I have used it for years on my dogs and it was recommended to me by a person that raw feeds her dogs and uses all natural and homeopathic cures for her animals. I mail order it from Jeffers pet supply.
here it is,
Flicks Essential oil spray
(Animal Legends) All-natural & biodegradable - concentrated horse fly spray. Contains: lanolin, (for coat conditioning), Oils of cedarwood, eucalyptus, lemongrass, peppermint, cajeput, pennyroyal (which are offensive to fleas, ticks, mosquitoes & flies). Contains no dyes. Available in 4 oz with empty 32 oz bottle (4 oz mixed with 28 oz water equal 32 oz) or 16 oz refill that makes a gallon.
I lived in northern calif on the beach and we had what we called super fleas, very hard to kill. I mixed it up and kept a spray bottle on my porch and encouraged all the pet owners to use as much as they needed. One lady told me after she used Advantage to kill fleas her dog was disorientated and staggered when he walked. Thats whaen I started putting it out for my neighbors and the dog never had to go through that again. At any rate those are the ingr. it will give you a starting place to make your own.