Optimising the delivery of synthetic and biological chemistry offers the post-harvest storage sector new possibilities

The 10th Conference of the IOBC Working Group on the Integrated Protection of Stored Products was held in Zagreb last month. Scientists from around the world presented a range of studies in relation to Stored Product Protection. Three of these presentations focussed on the novel reformulation of current chemistry and one presentation discussed the ongoing development of a new biological control for insects in stored grain.  Using Entostat wax as the delivery vehicle was the common theme across each of these three presentations.

The protection of stored food ‘post-harvest’ like most other sectors of the food supply chain is under pressure from three key drivers: consumer pressure to reduce residues, the consequent regulatory controls which remove traditional chemistry from the growers tool box and thirdly, insect pest resistance. These drivers have left this sector with limited options for pest control and with few alternatives in the pipeline.

The widening technology gap

Between 2005 and 2010, the EU reviewed more than 1000 pesticides which had been on the market since 1993 and removed 66% of them.  In the UK for example, the number of pesticides available for use in commercial grain stores has reduced from 17 to 6 and currently 10 species of arthropod found to infest grain have developed resistance to a range of insecticides. The limited availability of active ingredients only compounds the problem as the development of insect resistance to the remaining active ingredients occurs more quickly. New active ingredients may take up to ten years to become commercialised from the point of discovery, therefore innovation in the formulation of current chemistry is required in the meantime to fill this technology gap.

Entostat, doing more with less

Entostat is a proprietary wax micropowder which has unique electrostatic properties. By exploiting these natural physical properties, Entostat has been developed as a highly targeted delivery platform for synthetic and biological active ingredients. Essentially, better targeting and placement of active ingredients means that more can be achieved with less.

Freya Scoates, Research Scientist at Exosect, showed that when using Entostat as the delivery platform for deltamethrin and pirimiphos-methyl it was possible to reduce the amount of active ingredient by 50% and 90% respectively, while still achieving the same level of mortality of Sawtoothed Grain Beetle(Oryzaephilussurinamensis)compared to the commercial standard. Furthermore, this was achieved without using a synergist. Entostat was also used to successfully deliver both deltamethrin and pirimiphos-methyl in co-formulation, which offers further options to combat resistance.

Christos Athanassiou of the University of Thessaly demonstrated how Entostat formulated pirimiphos-methyl could be used to control four key pests of stored grain, Oryzaephilussurnamenis, Rhyzoperthadominica, Triboliumconfusum and Sitophilus oryzae. Results showed that an Entostat-based formulation of pirimiphos-methyl applied to grain provided up to twice the level of control than the conventional emulsifiable concentrate when applied at the same rate of active ingredient.

Dr.Subramanyam of the US Department of Grain Science and Industry at Kansas State University, presented studies also using Entostat to deliver pirimphos-methyl and deltamethrin at reduced concentrations.  These studies demonstrated a high level of adult mortality and excellent control of progeny.  He concluded that the Entostat formulations have potential as stored grain protectants.

The ability to reduce chemical inputs is very promising news for the industry while it waits for the commercialisation of Bb38, a new biological treatment for grain silos. Biologicals like the Beauveriabassiana in Bb38 have, for a long time, been potential candidates for insect pest control however the formulation and delivery of these types of organisms has presented issues with spore viability, longevity and optimal distribution. Formulation with Entostat addresses these issues. Bb38 will be the first biological formulation for use in grain stores. The isolate is now under review with EU regulatory bodies.