Call your Local Nursery's, ask if they have "Live" Beneficial Nematodes. For $8.00 bucks, you get 1 to 2 million. They come on a small blue sponge within a zip-lock bag, kept in the fridge. Don't buy the ones in a soil type package. If they don't have the live ones, get on-line, & order them. Once you get them, soak the sponge in 5 or more gals. of water, slosh the sponge around to wash them off into the water. Soak, slosh (carefully) for 10 minutes. In the meantime, wet down all the areas that dogs like to lay, & Play. Then, sprinkle, pump spray, hose in spray, whatever, in the area.
These Babies will seek a "Host", Flea, Ant, Tick, Grub, etc., eggs, and lay eggs in the Host, causing 1,000's of baby Nematodes. In about 1 week, no more fleas. To keep them fed, ask your friends to bring their flea infested dogs over. Yes. No posion, like flea collars. They should be outlawed. Any further questions, feel free to ask. To kill intestine parasite, DE does the job, no Posion pills. Ask Your Vet.