Changes in Essential Oil Composition and Volatile Emissions of Minthostachys mollis, Induced by Feeding Punctures of Liriomyza huidobrensis.

BANCHIO, E., VALLADARES G., ZYGADLO, J AND GIORDANO, W.

Barcelona

Congreso; Annual Meeting, International Society of Chemical Ecology; 2006

International Society of Chemical Ecology

Plants defensive mechanisms against herbivores include chemical changes following damage. This possibility was analysed for Minthostachys mollis, a Lamiaceae native to Central Argentina with medicinal and aromatic uses in the region. Effects of feeding punctures produced by Liriomyza huidobrensis adult females on the plant’s dominant monoterpenes pulegone and menthone, were assessed by monitoring essential oil composition at 24, 48 and 120 h; emission of volatiles was also measured 24 and 48 h after wounding. Leaf puncturing resulted in reduced menthone throughout the experiment and increased pulegone concentration in M. mollis essential oil during the first 48 hours. The adjacent undamaged leaves showed similar changes, suggesting a systemic response. Composition of volatiles released from M. mollis damaged leaves was also altered, most noticeably by increasing pulegone and diminishing menthone emissions, resulting in a reversal of relative representation of both compounds. It is likely that changes in both oil concentration and headspace serve important ecological roles during the leaf postwounding period. Moreover, from a commercial point of view, the effects of wounding on leaf oil composition could also have an important impact, since the quality of essential oils and volatile emissions can be altered.