Synergistic and residual pesticidal compositions containing synergistic and residual mixtures of plant essential oils in admixture with enzyme inhibitors, with or without other compounds not previously used as active ingredients in pesticidal formulations. 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.