How I wish that were true. Unless you live north of the 45th parallel, fleas will continue to be a problem for weeks, maybe months to come. In my practice area, we see our heaviest flea problems from late August through October. Right now, let's have a quick refresher course. Adult fleas feed on blood, and prefer to spend most of their time on the host animal.
Females bite the dog, taking a blood meal.
They then lay their eggs, which DROP OFF the pet into its environment. The egg hatches into a larva which eventually forms a cocoon, emerging as an adult flea ready to seek a new host. The vast majority are in the egg and larval stages of development. Unfortunately, most owners first want to spray their yard. A lovely way to spend an afternoon I am sure, but not the most effective way to control fleas.