Abstract: A method of termite control consists of injecting a foam formulation above ground into the walls of a structure infested with termites or other undesirable pests. The inner spaces of affected walls are flooded at and above ground level to ensure that the foam formulation reaches all passages open to the soil under the structure and establishes an above-ground layer of pest-control chemicals. The foam penetrates all porous material exposed to the injection and impregnates it with active ingredients that remain embedded in the material long after the foam disappears, thereby retaining the insecticidal, repellant and preservative properties of the active agents for a long time without exposure to normal degrading forces. The pest-control formulation preferably comprises pesticide, repellant and preservative components, and a foaming agent in a liquid carrier.