Synergistic and residual pesticidal compositions containing synergistic and residual mixtures of plant essential oils and/or their constituents, plant essential oils and/or their constituents in admixture with known active pesticidal compounds or plant essential oils and/or their constituents in admixture with other compounds not previously used as active ingredients in pesticidal formulations, such as, for example, so called signal transduction modulators. In addition, the present invention is directed to a method for controlling pests by applying a pesticidally effective amount of the above synergistic and residual pesticidal compositions to a locus where pest control is desired.