Assessing the Insecticidal Performance of Commiphora myrrha Essential Oil Against Prostephanus truncatus and...

Botanical insecticides have gained interest due to a rising demand for environmentally friendly pest control methods for stored-product protection. The insecticidal effectiveness of the essential oil (EO) obtained from the oleo-gum-resin of myrrh (Commiphora myrrha (Nees) Engl.), against Prostephanus truncatus (Horn) and Sitophilus zeamais Motschulsky, and the metabolic shifts of the two species, were investigated in this work. A thorough gas chromatography-mass spectrometry (GC-MS) investigation showed that the composition of this EO was dominated by furanosesquiterpenes, specifically, furanoeudesma-1,3-diene and curzerene. Commiphora myrrha EO treatments, especially at 1000 ppm, resulted in high adult mortality for P. truncatus (up to 85.6%), while S. zeamais showed only moderate mortality (up to 25.6%). To investigate the different species-specific effectiveness of the EO, untargeted GC-MS metabolomic profiling was conducted to elucidate the impact of the EO on the metabolism of the insects, with subsequent data analysis employing multivariate, univariate, and network methods. Each species reacts differently to the treatments (myrrh EO versus the synthetic insecticide pirimiphos-methyl (PM)), according to the analysis results. In particular, myrrh EO caused distinct shifts in metabolic pathways that varied between P. truncatus and S. zeamais. Overall, C. myrrha EO exhibits potential as a botanical insecticide, especially against P. truncatus, and it causes metabolic disturbances specific to the species. The results demonstrate the significance of metabolomic technologies in assessing bioinsecticide mechanisms and lend credence to their possible incorporation in integrated pest management methodologies or their contribution to the creation of diagnostic indicators of insecticidal exposure.