- Contact Kill and Residual Action
- What the Products Actually Are
- Resistance, Plainly
- Why Application Matters More Than the Product
- What the Treatment Cannot Do
Almost everyone rings us having already tried something. Understanding why that something did not work is usually the quickest way to explain what we are going to do instead.
Contact Kill and Residual Action
Insecticides do one of two jobs, and good bedbug work uses both.
Contact
Kills what it lands on, at the moment it lands. Useful when you can see the insect, useless for the nine out of ten you cannot — and with bedbugs, you almost never see the majority of the population.
Residual
Left on a surface, stays active, and kills insects that walk over it afterwards. This is the part that does the real work, because it turns the routes bedbugs must use into places they cannot cross safely. They come out to feed; the residue is between them and you.
A shop aerosol is almost entirely contact, evaporates quickly and leaves very little behind. A professional treatment is placed deliberately as a residual barrier and left to work for weeks.
What the Products Actually Are
Broadly, professional bedbug work draws on three families, used together rather than in isolation:
- Synthetic pyrethroids — the long-standing backbone, fast-acting, and the family most affected by resistance in urban populations
- Neonicotinoids — a different mode of action, which matters precisely because it sidesteps pyrethroid resistance
- Desiccant dusts — not poisons at all. They abrade and dehydrate, they never stop working, and resistance to them is not really possible. They go into voids, sockets and under carpet edges rather than on open surfaces
Using more than one mode of action in the same treatment is not belt-and-braces. It is the standard answer to resistance, and a treatment relying on a single pyrethroid in a London flat in 2026 is asking to fail.
Resistance, Plainly
Bedbug populations in big cities have been exposed to the same chemistry for decades, and some of them carry genes that let them shrug it off. That is not a rumour, it is the reason professionals rotate products and combine modes of action.
It is also the reason a member of the public buying the same supermarket spray three weeks running is, in effect, running a selective breeding programme in their own bedroom.
Why Application Matters More Than the Product
Given two technicians and the same product, the results will differ enormously, because bedbug treatment is a searching job rather than a spraying job.
The product has to be placed where the insects walk, in the cracks they occupy, at the right rate, on surfaces that will hold it. Treating the open face of a mattress achieves almost nothing. Treating the piping, the seam, the label pocket, the frame joint and the screw holes achieves nearly everything.
That is also why a treatment takes an hour or two rather than ten minutes. Most of it is looking.
What the Treatment Cannot Do
It cannot kill the eggs reliably, and it is not supposed to. That is the whole reason there is a second visit, and any quote that omits the second visit has removed it from the price rather than from the job.
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Related Questions
Is it safe around children and pets?
The products are applied to harbourages by a trained technician rather than sprayed around a room, and everyone stays out until surfaces are dry. Tell us beforehand about pregnancy, respiratory conditions, fish tanks or caged birds and we will work round them.
Why can I not just buy the same thing?
The professional products are not sold to the public, and the difference in outcome is mostly application anyway. The most common result of DIY is bedbugs scattered out of treatable harbourages into wall voids.
Will it smell?
Very little, and what there is goes within a few hours. If a strong smell matters to you, say so and we will talk about heat instead.
Bedbug Chemical Treatment London — Advice
Everything else written up for this service, and the service page itself if you would rather just get a price.
Tell Us About the Property
Tell us what you have seen and where, and we will tell you what it needs.