Compositions and methods for synergistic pesticidal mixtures comprising a first pesticidal composition and a second pesticidal composition, wherein the pesticidal activity of the mixture exhibits synergistic effects compared with the expected effects of the mixtures based on the sum of the activity of the first pesticidal composition alone and the activity of the second pesticidal composition alone. Synergistic pesticidal mixtures and methods according to the invention are provided comprising a first pesticidal composition comprising at least two essential oils, a carrier oil, and an emulsifier, and a second pesticidal composition comprising at least one insecticide, wherein the pesticidal activity of the mixture is greater than the sum of the activity of the first pesticidal composition alone and the activity of the second pesticidal composition alone. Methods are provided for screening and identifying synergistic pesticidal mixtures according to the invention.
