Residual insecticides for IRS are generally in the form of powders or liquids. Water-dispersible powder consists of a powdered insecticide mixed with a substance that allows the insecticide to dissolve in water. For indoor spraying purposes, the water-dispersible powder is the most effective form. Any of the insecticides shown in the table below can be used for IRS. Most insecticides come in pre-weighed sachets; one sachet is to be used per one spray pump of eight litre capacity.
| Name of insecticide | Chemical type | Dosage (in grams per square metre) |
|---|---|---|
| Malathion | Organophosphorus | 2 g/m2 |
| Fenitrothion | Organophosphorus | 1 or 2 g/m2 |
| Propoxur | Carbamets | 1 or 2 g/m2 |
| Bendiocarb | Carbamets | 0.2–0.4 g/m2 |
| Deltamethrin | Synthetic pyrethroids | 0.025–0.05 g/m2 |
| Permethrin | Synthetic pyrethroids | 0.5 g/m2 |
| Lambdacyhalothrin | Synthetic pyrethroids | 0.025–0.05 g/m2 |
| Cypermethrin | Synthetic pyrethroids | 0.5 g/m2 |