I have an 8 pound Pomeranian who is hyper-sensitive to fleas. We recently moved into a new-to-us home that was obviously a home to fleas. Here is the recipe that helped us and other things we learned on the way.
flea/tick/mosquito spray: up to 15 drops (total) of oils in a spray bottle. Shake well, mist your dog daily. Spray on bedding, around doorways & baseboards to keep insects out. *Mist your own skin, hair & clothing when outside. Place a few dr - Picmia