Listen to Boogaloo. You've got the break the hatch cycle of the fleas or you'll never get rid of them. That means spraying the yard with your insecticide about every three days for several weeks as new fleas are constantly hatching. You can kill them all once and in a couple of weeks you'll have just as many as you did before as the new ones hatch. You can kill the fleas but you can't kill the eggs so you need to keep after them until all the eggs in your yard have hatched and you've killed the resulting adults. Only then will you get a handle on them.
