Antagonistic storage potential of Tagetes minuta, Eupatorium fortunei and Ocimum basilicum oils with volatile secondary metabolites against Tribolium castaneum and Lasioderma serricorne

Abstract

Antagonistic storage potential of Tagetes minuta Linnaeus, Eupatorium fortunei Turcz. and Ocimum basilicum L. volatile oils hydrodistillated with main secondary metabolites against two storage pests, Tribolium castaneum and Lasioderma serricorne adults were evaluated. More than 95% volatile secondary metabolites obtained at different hydrodistillation time were identified by gas chromatography-mass spectrometry (GC-MS), and analyzed with principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). Further insecticidal assay exhibited interesting results that T. minuta oil showed the strongest fumigant toxicity against both T. castaneum (LC50 = 6.68 mg/L air) and L. serricorne (LC50 = 3.13 mg/L air) among the three essential oils. As one of the main volatile secondary metabolites, methylthymol was found to possess more powerful fumigant (LC50 = 2.42 mg/L air) and contact toxicity (LD50 = 5.43 µg/adult) against T. castaneum. While, precocene I exhibited the strongest insecticidal toxicity on L. serricorne with the LC50 value of 0.88 mg/L air and LD50 of 3.46 µg/adult, respectively. During the repellent assay, T. minuta oil showed the same repellent rate against both T. castaneum and L. serricorne at the highest concentration of 78.63 nL/cm2. The results proved that the essential oils as well as the main volatile secondary metabolites have potential to be developed into novel natural botanical resources on antagonistic storage with traditional Chinese medicine (TCM).