Optimising the delivery of pesticide to grain using Entostat® to reduce the amount required for effective control

Abstract: There is significant pressure to reduce the use of chemical pesticides in stored grains and other dried commodities for operator safety and because residues can lead to consumer rejection. However, growers are keen to keep pesticides as one of a suite of tools under an IPM approach. Optimising the delivery of the pesticide can reduce the amount required for effective control. Entostat® is an electrostatic micro-powder formulated using blends of waxes and polymers, which can have an active ingredient dispersed within its matrix. It adheres to insectcuticles and grain kernels and thus can be used to effectively target storage pest species, increasing the exposure of the insect to the pesticide and evenly distributing in grain during admixture. Deltamethrin and pirimiphos-methyl were formulated in Entostat, without the synergist PBO, at rates ≤ half that of a conventional deltamethrin-based formulation. In a series of studies control of four significant grain pests: Sitophilus granarius (L.), Oryzaephilus surinamensis (L.), Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst), was achieved equivalent to the conventional formulation. We demonstrated that by improving the delivery, using a carrier such as Entostat, it is possible to apply chemical pesticides at much lower concentrations than are currently used, while achieving equivalent levels of control. This indicates that there is significant potential for chemical pesticides to continue as an important component in storage IPM.