Chemical Composition of the Headspace Volatiles from Chromolaena odorata (L.) R.M. King in Ghana

Abstract

Many natural enemies of herbivorous insects are attracted to semiochemicals emitted by plants. Semiochemicals emitted by host plants can prime neigbouring plants to adjust their defensive mechanism against future attack. Crop protection, using plant signal is recently gaining momentum due to health and environmental concerns about the use of synthetic pesticides. Semiochemicals have successfully been used to protect maize from the stem borer through the Push /Pull technology. Chromolaena odorata plant is known to support a large and varied insect fauna although the chemistry involved has not been fully established. To determine the volatiles emitted by the undamaged C. odorata plant that might be associated with the insect plant interaction, Dynamic headspace technique was used to collect volatiles from the plant under laboratory conditions and analysed using a Gas chromatography and Gas Chromatography coupled with Mass Spectrometer (GC-MS). Thirty three compounds were identified from the collected headspace volatile from the plant. (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), 4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT) and E-β-farnesene are three semiochemicals identified that had not been reported to be emitted by an intact C. odorata plant from Ghana.

Key words:

• Chromolaena odorata
• Semiochemicals
• Headspace volatiles