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The essential oil was obtained from the aerial parts of Pogostemon cablin by hydrodistillation. The chemical compounds of P. cablin essential oil were analyzed by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. Eight compounds were totally identified and accounted for 92.4% of the oil. Patchoulol was the major component (51.1%), followed by phloroacetophenone (23.5%) and β-patchoulene (7.3%). The essential oil and its two major compounds patchoulol and phloroacetophenone were evaluated for their contact and repellent activities against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila. Results of bioassays indicated that the essential oil and patchoulol had great contact toxicity against three species of insects. Meanwhile, the essential oil and patchoulol showed great repellent activities against T. castaneum and L. bostrychophila but were mildly repellent to L. serricorne. Phloroacetophenone exhibited neither contact nor repellent activity against any of these target insects. This work emphasized the promising potential of P. cablin to control insect pests during storage.

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Thymus quinquecostatus Celak. of the Lamiaceae family has a long history of dual use of medicine and food with high economic value, and has been proved to have good antioxidative, antimicrobial, and antidiabetic activities. Essential oil (EO) extracted from the aerial part of T. quinquecostatus was obtained by hydrodistillation and analyzed by gas chromatography‐mass spectrometry (GC/MS) and GC. Totally 45 compounds were identified accounting for 98.5 % of the EO. The major constituents of the EO were linalool (52.003 %), borneol (10.911 %) and anethole (5.325 %). Fumigant, contact and repellent activity of T. quinquecostatus essential oil (EO) against Tribolium castaneum (Coleoptera: Tenebrionidae), Lasioderma Serricorne (Coleoptera: Anobiidae), Liposcelis bostrychophila (Psocoptera: Liposcelididae) were evaluated in this work. T. quinquecostatus EO and three major constituents showed varying degrees of insecticidal and repellent activities to three stored‐product insects. Anethole stated the best fumigant and contact activity than others did to all three insect species. EO and compounds showed general repellent activity against three target insects. This work suggests that the EO of T. quinquecostatus has promising potential to be developed into botanical pesticides and repellents controlling pest damage in warehouses and grain stores.

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