Insect Control Sprays

It depends what you are trying to do.

• Pesticide-free sprays: no synthetic pesticide in the formulation, which is the reason to choose one in a kitchen or a pet household. They act on the insects they reach and do not leave a treated surface behind.
• Fast knockdown sprays: for quick control of insects you can see, or an active spot you have found.
• Residual sprays: a dried-on film that keeps working on surfaces insects cross later, which is what you want for repeat activity.
• IGR sprays: insect growth regulators, which interrupt development so immature insects cannot mature and breed. Used alongside another spray rather than on their own.

It depends on the type of spray.

• Fast knockdown: target visible insects directly, or spray exactly where you have seen activity. With no insects present, a knockdown spray does very little.
• Residual: treat pathways and harbourages - skirting edges, cracks and crevices, behind appliances, under sinks, inside cupboard gaps and around entry points. Once dry it keeps working as insects cross it.
• IGR: apply to harbourages and breeding hotspots, the same hidden areas as a residual, and pair it with a knockdown or residual product. Results are gradual by design, so do not expect to see anything immediately.

Follow the label directions, and do not spray food-preparation surfaces unless the label specifically allows it.

The range includes both pesticide-free sprays and insecticides, and the product page states which is which. Whichever you use, keep children and pets out of the room while you spray and until treated surfaces are completely dry, ventilate as you work, cover fish tanks and move pet bowls and bedding out first. Apply into cracks and edges rather than across open floor, and do not treat food-preparation surfaces unless the label allows it.

The pattern tells you which mistake it is. If you knocked insects down and more appeared within days, only the ones out in the open were treated and the harbourage was never reached - switch to treating the cracks, voids and spaces behind appliances rather than the open room. If you treated surfaces and saw no change at all, either insects are not crossing where you sprayed, or you are using a knockdown product where a residual one is needed. Put out monitoring traps for a few nights and let those show you where to work.

A spray treats what is inside; it does not close the way in. Check gaps under doors, around pipework, airbricks, vents and window frames, and look for damp, which is what draws silverfish and woodlice in the first place. Our guide to insect proofing a home or business covers the gaps worth closing, and insect proofing products are what stops the cycle repeating next season.

If activity continues after a full treatment cycle in line with the label, if it has spread beyond one room, if you are dealing with bed bugs or German cockroaches, or if there are vulnerable occupants in the property. Look for a qualified pest controller with BPCA membership.