Fumigant and repellent properties of sesquiterpene-rich essential oil from Teucrium polium subsp. capitatum (L.)

ObjectiveTo test fumigant and repellent properties of sesquiterpene-rich essential oil from Teucrium polium subsp. capitatum (L.).MethodsThe fumigant toxicity test was performed at (27±1)°C, (65±5)% relative humidity, and under darkness condition and 24 h exposure time. The chemical composition of the isolated oils was examined by gas chromatography-mass spectrometry.ResultsThe major compounds were α-cadinol (46.2%), caryophyllene oxide (25.9%), α muurolol epi (8.1%), cadalene (3.7%) and longiverbenone (2.9%). In all cases, considerable differences in mortality of insect to essential oil vapor were observed in different concentrations and exposure times. Callosobruchus maculatus (C. maculates) (LC50=148.9 μL/L air) was more susceptible to the tested plant product than Teucrium castaneum (T. castaneum) (LC50=360.2 μL/L air) based on LC50 values. In the present investigation, the concentration of 3 μL /mL acetone showed 60% and 52% repellency against T. casteneum and C. maculatus adults, respectively.ConclusionsThe results suggests that sesquiterpene-rich essential oils from the tested plant could be used as a potential control agent for stored-product insects.