11 7 min read Guide

The flea life cycle and why one spray never holds

Adult fleas are five percent of the problem. The eggs, larvae and pupae hiding in carpet, bedding and soil are the rest. Why a single spray fails, what a growth regulator does, and the aftercare that makes the difference.

A single flea spray feels like it should fix the problem. It kills the adults on contact, the biting stops, and a week later they are back. The reason is that what you saw jumping was only about five percent of the flea population in your home. The rest, the eggs, larvae and pupae, are hidden in carpet pile, bedding, cracks and yard soil, and a surface spray does not reach them.

The four stages

Understanding why one treatment is never enough comes down to knowing what you are actually dealing with.

Why the cycle breaks with a proper program

A professional flea treatment does two things at once. The residual product kills adults and exposed larvae on contact. The insect growth regulator (IGR) sterilises eggs and prevents larvae from developing into adults. Together, they collapse the population within one generation cycle, typically two to four weeks.

The IGR is the part a supermarket spray does not have. Without it, you kill today's adults and tomorrow's hatch replaces them.

The fleas you see are five percent of the problem. The eggs, larvae and pupae you cannot see are the other ninety-five.

Aftercare that makes the treatment work

Common questions

How long does it take to get rid of fleas after a treatment?
Expect full control within two to four weeks. The treatment kills adults and larvae on contact, but pupae in their cocoons are protected until they hatch. The insect growth regulator prevents new eggs developing, so the population collapses within one generation cycle. Seeing a few new fleas in the first week or two is normal and expected.
Do I need to treat my pet as well as the house?
Yes. Both need to happen at the same time. If you treat the house but the pet is still carrying fleas, they re-seed the carpets within days. Your vet can recommend the right product for your pet; the pest controller handles the house and yard.
Can fleas survive without a pet in the house?
Yes. Flea pupae can remain dormant in carpet for months, waiting for vibration, warmth or CO2 to signal a host is nearby. This is why tenants moving into a previously vacant house with carpet sometimes get bitten within hours of walking through the door.
Is the treatment safe for my baby who crawls on the carpet?
Once the treatment has dried and the re-entry time has passed, usually two to four hours, the risk is very low. The products are APVMA-registered for domestic use. Your operator should give you a clear re-entry time in writing before they start.

Common questions

How long does it take to get rid of fleas after a treatment?
Expect full control within two to four weeks. The treatment kills adults and larvae on contact, but pupae in their cocoons are protected until they hatch. The insect growth regulator prevents new eggs developing, so the population collapses within one generation cycle. Seeing a few new fleas in the first week or two is normal and expected.
Do I need to treat my pet as well as the house?
Yes. Both need to happen at the same time. If you treat the house but the pet is still carrying fleas, they re-seed the carpets within days. Your vet can recommend the right product for your pet; the pest controller handles the house and yard.
Can fleas survive without a pet in the house?
Yes. Flea pupae can remain dormant in carpet for months, waiting for vibration, warmth or CO2 to signal a host is nearby. This is why tenants moving into a previously vacant house with carpet sometimes get bitten within hours of walking through the door.
Is the treatment safe for my baby who crawls on the carpet?
Once the treatment has dried and the re-entry time has passed, usually two to four hours, the risk is very low. The products are APVMA-registered for domestic use. Your operator should give you a clear re-entry time in writing before they start.
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