CONICET | Buscador de Institutos y Recursos Humanos

The use of active natural compounds derived from plants appears as an interesting alternative for pestcontrol in stored products. In this study, the fumigant toxicity of several terpene ketones against maizeweevil (Sitophilus zeamais) adults was assessed, and the effect of their combination with piperonylbutoxide (PBO), a cytochrome P450 inhibitor commonly used as synergistic agent, was investigated. Amixture of the most active ketones (R-(þ)-pulegone and thymoquinone) was then tested on S. zeamais,and finally this mixture was incorporated into low density polyethylene (LDPE) films by supercritical CO2impregnation, in order to study the fumigant toxicity of this formulation against S. zeamais under laboratoryconditions, as well as the release profile of the active ketones. PBO showed antagonistic effects incombination with terpene ketones, decreasing the toxicity of the individual compounds and thereforeincreasing their lethal concentrations. The mixture of ketones showed a lower lethal concentration (LC50value of 7.12 mL/L air) than the individual compounds, thus indicating a synergistic effect between them.Finally, the impregnated films revealed high toxicity values (up to 95% mortality), and maintained amoderate level of activity even after 8 days of exposure. In conclusion, the mixture of these activeterpene ketones incorporated into a polyethylene film, material commonly used for hermetic storage ofmaize grains, could be applied as a potential technology against insect pests.