Why should some insecticide formulations be watered in?

Watering in insecticide formulations is often recommended to ensure effective control of soil-dwelling pests. By applying water after the insecticide is spread, it helps to move the active ingredients into the soil where pests reside, making the insecticide more effective. This process can also draw soil insects closer to the surface, where they may be more exposed to the insecticide, thus increasing the likelihood of contact and control.

For instance, some pests may burrow deep into the soil or hide in protected areas to escape treatment. By watering in, you encourage their movement within the soil profile, improving the contact points for the insecticide. This practice maximizes the pest control potential of the treatment and can lead to more effective eradication of pest populations.