What Chemical Kills Fleas and Their Eggs?

The reason flea infestations keep coming back is that most products only kill adult fleas, and adults are less than five percent of the population in your home. The eggs, larvae and pupae hiding in carpet, bedding and floor cracks are untouched, and a new wave hatches a week later. Ending an infestation means killing adults and stopping the eggs from developing at the same time.

The two chemicals that work together

Insect growth regulators (IGRs). Methoprene and pyriproxyfen are the two used in professional flea control. They do not kill adult fleas. They mimic a flea hormone so that eggs never hatch and larvae never mature. A single application keeps working for months, which is what breaks the cycle.

Adulticides. These kill the adult fleas that are biting now. Professional products use pyrethroids or newer chemistries such as fipronil or dinotefuran. Over the counter sprays often use permethrin, which works but wears off quickly and to which some flea populations are resistant.

A treatment that combines an IGR with an adulticide is the only chemical approach that handles every life stage. Either one alone fails.

What chemicals cannot do

No spray kills flea pupae. The cocoon protects them, and they can wait weeks before emerging when they sense warmth and movement. That is why you may still see a few fleas a week or two after a treatment. The IGR left behind stops them from breeding, and they die without producing a new generation.

The steps that make the chemicals work

1. Treat the pet the same day. A veterinarian prescribed flea product on every dog and cat in the house. Untreated pets re seed the home.
2. Vacuum everything first. Carpets, rugs, under cushions, along baseboards. Vacuuming removes eggs and the vibration makes pupae emerge so the adulticide reaches them. Empty the vacuum outside.
3. Wash bedding hot. Pet beds, throws and any bedding the pet uses, on the hottest setting.
4. Treat inside and out. Shaded areas of the yard where pets rest are flea nurseries in Florida. The perimeter and those spots get treated along with the interior.
5. Keep vacuuming for two weeks. Daily if you can. It is the single most effective thing a homeowner does after a treatment.

Are these chemicals safe for my family?

Applied correctly, yes. IGRs act on a hormone insects have and people and pets do not. Adulticides are applied as a fine treatment to floors and resting areas, and you stay out until it is dry, usually two to four hours. Always tell your technician about fish tanks, reptiles and anyone in the home with asthma so the treatment can be adjusted.

Uprooted Weed and Pest Control treats flea infestations in Dunedin, Clearwater, Largo and Palm Harbor with an IGR and adulticide program and a follow up visit built in. If you have been spraying for weeks and the fleas keep returning, that is the cycle we break.

Related reading

• How Do I Prepare for Flea Extermination? A Room by Room Checklist
• Why are bed bugs so hard to get rid of
• What Time of Year Are Bugs Most Active in Florida?