A synergistic mixture of diatomaceous earth and deltamethrin to control stored grain insects

  • C. Korunic Diatom Research and Consulting Inc., 14 Tidefall Dr. Toronto, ON, M1W 1J2, Canada.
  • V. Rozman Faculty of Agriculture in Osijek, University of J. J. Strossmayer in Osijek, Trg Sv. Trojstva 3, 31100 Osijek, Croatia


In order to mitigate the negative effect of diatomaceous earth (DE) on bulk density and grain flowability, DE was mixed with other insecticides. This paper investigates the efficacy of a mixture of DE and deltamethrin against Sitophilus zeamais, the maize weevil, Rhyzopertha dominica, the lesser grain borer, and Tribolium castaneum, the red flour beetle. Five mixtures of DE and deltamethrin were prepared in the laboratory containing the same quantity of DE and different concentrations of the active ingredient of deltamethrin. The ratio of DE and deltamethrin in formulations were: DE 1 part: deltamethrin 0.00025, 0.00050, 0.00075, 0.0010 and 0.00125 parts. Co-toxicity and Co-efficient values higher than 100 (S. zeamais 170–386, R. dominica 188–601, and T. castaneum 157–285) indicated synergism between DE and deltamethrin.

Keywords: Diatomaceous earth, Deltamethrin, Ready to use mixture, Co-toxicity, Co-efficient, Synergism, Grain insect pests
Section: Residual Insecticides - Synthetic and Botanical