Chemical Composition, Repellent Action, and Toxicity of Essential Oils from Lippia origanoide, Lippia. alba Chemotypes, and Pogostemon cablin on Adults of Ulomoides dermestoides (Coleoptera: Tenebrionidae)

SIMPLE SUMMARY: Essential oils (EOs) from plants are promising products for pest management. This paper describes the chemical composition and repellent action of four EOs against Ulomoides dermestoides, a common pest on several stored products. Most abundant chemical components found in the EOs were sabinene, trans-β-caryophyllene, and α-humulene for phellandrene-rich Lippia origanoides; limonene and carvone for carvone-rich Lippia alba; geranial, geraniol, and neral for citral-rich Lippia alba; and α-guaiene, α-bulnesene, and patchoulol for Pogostemon cablin. The repellent bioactivity, carried out utilizing the area preference method, showed that all EOs displayed great repellency with low mortality rates, suggesting these natural mixtures can be used in formulations of repellents against stored grain pests. ABSTRACT: The essential oils (EOs) from bioactive species can provide an alternative tool for the management of stored grain insects that is less environmentally damaging than synthetic chemicals. The aim of this study was to assess the repellent action and toxicity of EOs obtained from phellandrene-rich Lippia origanoides, carvone-rich Lippia alba, citral-rich L. alba, and Pogostemon cablin aerial parts on adults of Ulomoides dermestoides. These EOs were isolated by hydrodistillation and characterized by gas chromatography coupled to mass spectrometry (GC-MS). The repellency assay was carried out using the area preference method, and the toxicity evaluated utilizing a filter paper contact test. The major components (>10%) of the studied EOs were sabinene (16.9%), trans-β-caryophyllene (18.6%) and α-humulene (10.1%) for phellandrene-rich L. origanoides EO; limonene (40.1%) and carvone (37.7%) for carvone-rich L. alba EO; geranial (24.5%), geraniol (19.0%), and neral (11.9%) for citral-rich L. alba EO; and α-guaiene (13.3%), α-bulnesene (15.7%), and patchoulol (35.3%) for P. cablin EO. All EOs displayed 100% repellency at a concentration of 16 μL/mL, with lower toxicity than that elicited by the commercial repellent DEET. EO concentrations up to 8 µL/mL did not induce any mortality on the beetle. These findings show that the EOs provide active and safe molecules for natural repellent formulations to prevent and control insect infestations of stored products.