Environmental Flea Control

The most important concept to get in flea control is that 90-95% of the total flea population is made up of juveniles. Only the last 5-10% are the adults that we see! Adult fleas are obligate to stay on their host and rarely get off. The flea life cycles begins when a mommy flea and a daddy flea love each other very much, and they may decide to make a few hundred baby fleas.

The female will take blood meals on the host and use that energy to produce tons of eggs that she lays on the host. The eggs dry up a bit and fall off the pet and into the environment.

Eggs hatch and little larva crawl out and start feeding on the little bits of dirt, dander, fungi, etc in the carpet base, couch cushions, topsoil, or pet bedding that they happen to be hatched into.

After a couple of weeks, the larva spin this cool cocoon and begin to pupate. Pupae usually hatch out in another 10-14 days but can remain dormant in this state for a very, very long time.

There are two general classes of chemicals to use for environmental flea control. Adulticides (permethryn, Advantage, Frontline) all kill adults. The larva and eggs require something different. There are compounds called Insect Growth Regulators (IGRs) that will halt the development of these stages. The egg then dries up and goes away. The most common IGRs seen are methoprene (Precor) and pyriproxifen (Nylar). As a general rule, IGRs aren't very stable in the environment, so companies have had to develop delivery systems that help protect the chemical from light so that they will last long enough. Most preparations of Nylar for use in the home list a 3 to 4 month duration of action.

Don't waste your time putting down tons of chemicals on the lawn assuming that there are hoards of adult fleas waiting to invade. There aren't. The adulticide stuff you put down washes away and the flea larva continue to develop. The story is a bit different in the house where you have the opportunity to use a product that may bind to the carpet fibers and stick around for a while. A newly hatched adult may come in contact with the stuff and promptly die.

Apply a product including an IGR. I have seen one outdoor product that contains Nylar. There are several indoor products designed for use in carpets/furniture. Other IGR products are going to be designed to use ON the pet (Frontline Plus, Sentinel, Knockout).

Adulticide products for indoor use are usually of the permethryn/pyrethryn family. These usually last for a period of days to weeks and will kill newly hatched adults before they have a chance to get very far.

Borate powders are also popular amongst some folks. These powders can be worked into the carpets where they will dry out and kill the flea eggs and larva. They are seen by many as a "safer" alternative to chemicals. They are quite safe, but are a bit of a mess to apply.

One final word: Notice I haven't mentioned anything that kills pupae? There really isn't anything short of fire. That'll kill 'em. This is important to keep in mind because it means that no matter how effective our adulticide and IGR program is, there is a population of fleas waiting to hatch out over the next couple of weeks. This is why you must remain diligent and expect that it will take some time to resolve the problem. One treatment on the dog and the house won't do it.

AMH