Volatiles potentially useful to be used as biomarkers for monitoring the khapra beetle Trogoderma granarium for quarantine

The khapra beetle, Trogoderma granarium, is one of the most important quarantine pests globally. In order to identify potential biomarkers for establishing a rapid and effective monitoring technology for T. granarium quarantine, headspace-solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrum (GC-MS) was used to identify volatiles that are potentially useful for early detection of the presence of the T. granarium presence. Three volatiles, including Ethyl palmitate, (Z)-5-tetradecenoic acid and (Z)-14-methyl-8-hexadecen-1-al, were commonly identified as unique volatiles emitted from four different stored products including peanut, barley, wheat and rapeseed only after T. granarium infestation. In addition, four volatiles including hexadecane, palmitic acid, (Z)-14-methyl-8-hexadecen-1-al and N-heptadecane, were found emitted commonly from the larvae of T. granarium after they fed on the four stored products. These common chemicals could potentially be biomarkers sensitive enough for monitoring the presence of T. granarium. In addition to these unique chemicals, a combination of up- and down-regulated volatiles by each type of stored seeds were also identified as potential markers useful for the early detection of the presence of T. granarium. Our results could be a first step towards establishing a method for T. granarium monitoring and quarantine.