Chemical composition and fumigation toxicity of Laurus nobilis L. and Salvia officinalis L. essential oils on larvae of khapra beetle (Trogoderma granarium Everts)
The essential oil composition of bay laurel (Laurus nobilis L.), and sage (Salvia officinalis L.) leaves was investigated by GC and GC/MS. Composition of L. nobilis essential oil included large amounts of monoterpenes 85.90%, wheras in S. officinalis, monoterpenes and sesquiterpenes were represented by 57.3% and 41.7%, respectively. Fumigant toxicity of the essential oils was tested against larvae of Trogoderma granarium insect. Exposure to vapours of essential oil from bay laurel and sage for 48 h resulted in about 98% and 100% mortality of the larvae at a concentration of 60 and 90 μL/160 cm3 air, respectively. Essential oils of bay laurel showed a higher lethal activity than that of sage with LC50 values of 37.9 and 50.7b μL/L air, respectively, following a 48 h-exposure. These results showed that the essential oil from L. nobilis is potentially useful for management of T. granarium insects populations in stored products.