IGR Insecticide Sprays

An IGR, or insect growth regulator, does not work like a knockdown spray. It interrupts the insect life cycle so immature insects cannot develop properly, reducing the chance of the next generation building up. Think of it as a population tool rather than something that clears what is in front of you today.

Usually not. An IGR does nothing about the adults already in the room, so it is normally paired with a fast knockdown spray for the insects you can see now, or a residual spray on the pathways and harbourages. That covers the problem now and the next generation at the same time. It comes into its own with pests that have multiple life stages, such as fleas and bed bugs.

Where insects hide, breed and travel, rather than into open air:

• Skirting edges, corners, cracks and crevices
• Under and behind appliances, under sinks, inside cupboard gaps
• Harbourages and the active spots you have identified

Because an IGR works on development, results are gradual. Consistent placement and following the label directions matter more here than with any other spray type.

These are insecticides. 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, edges and the backs of units rather than across open floor, and do not treat food-preparation surfaces unless the label specifically allows it.

Quite possibly. An IGR is not meant to reduce what you can see this week - the adults already present live out their normal span whatever you do. What it should change is what comes after them, so judge it on whether new small insects keep appearing over the following weeks rather than on the count today. If adult numbers are the problem right now, add a knockdown or residual spray alongside it rather than reapplying the IGR more often.

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