Pesticide-Free Insect Control Powders

Diatomaceous earth - a fine powder with no synthetic pesticide in it, which works by physical action rather than by an active substance. It is the option for anywhere you would rather not put an insecticide down: a kitchen, a pet household, a cupboard base. It only works while dry, so it suits dry cracks, voids and skirting gaps and is a poor choice anywhere damp.

In the cracks, crevices and hidden spaces insects travel through. Apply a light, barely visible dusting to:

• Skirting joints, corners and floor edges
• Gaps around pipes under sinks and behind toilets
• Under and behind kitchen units and appliances, where you can safely reach
• Entry points such as thresholds and small gaps

Do not over-apply. A thin layer works better than a thick pile, because insects walk around a heap and through a film.

It keeps working as long as it stays dry and undisturbed - it is not used up as it works. Reapply if the dust has been cleaned away, vacuumed up, covered over, or has got damp. Anywhere near a leaking pipe or a damp cupboard base needs drying out first, because a wet layer has stopped working whether it looks like it or not.

Apply it into cracks, gaps and voids where it cannot be reached or disturbed, rather than across open floor. Avoid raising dust as you apply, and do not treat food-preparation surfaces unless the label allows it. Where the product is food-grade, that is stated on the product page. Follow the label directions.

It depends on the room and the problem. A pesticide-free powder is the sensible choice where you would rather not introduce an active substance, and it holds indefinitely in a dry gap. For a heavier or faster-moving problem you may want it alongside something else - our full powders and dusts range covers both types, and the product page states which you are buying.

Look at the dust rather than at the insect count. Undisturbed powder means nothing is using that route, so move it closer to where activity actually is. Powder that has clearly been walked through is doing its job, and what you are then judging is whether sightings fall week on week. Two to three weeks with no fresh activity is a reasonable all-clear.

If activity continues after a full treatment cycle, if it has spread beyond one room, or if you are dealing with bed bugs or German cockroaches, which are both hard to clear as a DIY job. Look for a qualified pest controller with BPCA membership.