Effect of peppermint leaf extract and peppermint oil on the flour beetle Tribolium castaneum (Coleoptera: Tenebrionidae)

The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is among the global storage pests that lead to the deterioration of grains and stored products. A series of laboratory experiments were conducted to evaluate the efficiency of different concentrations of Mentha piperita L. (Lamiaceae) oil and leaf methanol extracts against the rust-red flour beetle in the different instars. The results of the present study showed that the mint, M. piperita, oil treatments at all concentrations used (8%, 10%, or 12%) were significantly effective, resulting in remarkable individual mortality of T. castaneum third instar larvae and adult mortality compared to the treatment of the peppermint methanol leaf extract at the highest concentration. Peppermint oil showed insecticidal effect against the third instar larvae of the red flour beetle, especially where sprayed at the highest concentration of 12%. The post-treatment results after seventh days showed 94% adult mortality and 82% mortality in the third instar of larvae. This study confirmed the possibility of using mint essential oil at relatively low concentrations as environmentally friendly product in controlling the rust-red flour beetle T. castaneum.