1
∗Speaker
Agroecology and Ecology of Agroecosystems
Insecticidal activities of essential oil from (Miq.) C. DC., an endemic Piperaceae from Reunion island
Emmanuelle Dorla 1, Anne-Marie Cortesero 2, Fabrice Lamy 2, Amandine Ligoni`ere 3, Patricia Clerc 1, Jacques Fillatre 3, Patrice Marchand 4,
Henri Beaudemoulin 5, Toulassi Atiama-Nurbel 3, Philippe Laurent 1, Jean-Philippe Deguine 6, Isabelle Grondin ∗ 1
1 Laboratoire de Chimie des Substances Naturelles et des Sciences des Aliments, Universit´e de La R´eunion (LCSNSA) – R´eunion
2 Institut de G´en´etique, Environnement et Protection des Plantes, UMR INRA 1349 - Universit´e de Rennes 1 (IGEPP) – Universit´e de Rennes I – France
3 Association R´eunionnaise pour la Modernisation de l’Economie Fruiti`ere, L´egumi`ere et Horticole (ARMEFLHOR) – R´eunion
4 Institut Technique de l’Agriculture Biologique – ITAB – France 5 Soci´et´e Horticole de Bassin Plat (SHBP) – R´eunion
6 UMR Peuplements V´eg´etaux et Bioagresseurs en Milieu Tropical - CIRAD (PVBMT) – R´eunion
The future of agriculture and its economic, sanitary and ecological sustainability depend on a significant and expected evolution of crop protection practices, which today are too dependent on the use of synthetic pesticides. It is within this framework that biocontrol tools based on the use of plants or plant extracts are developed. Reunion’s chemiodiversity presents a great wealth and promising prospects in this context. The challenge of the BIOPIPER project was the sustainable production of the natural extracts of two Piperaceae, with the prospect of their use within the framework of the agroecological protection of crops against pests. Within this framework, the aims of the study presented here were to i/assess the biocidal properties of the essential oils obtained from deferent ecotypes of Piper borbonense against pests of economic importance worldwide, ii/
compare the sensitivity of some of these pests and their natural enemies towards these essential oils and iii/ identify the potential toxic compounds involved and assess whether or not their proportions and presence are modified in wild vs cultivated plants. Contact tests on filter papers impregnated with essential oils showed that they were highly toxic to a large range of pest insects (LD50 ranged between 36 and 183 mg/cm2). Comparison of toxicity of essential oils on some pests and their natural enemies indicated that the later were less sensitive but still affected by these oils. Five phenylpropanoids dominated the composition of active essential oils: asaricin, safrole, elemicin, dillapiole and myristicin. Although some variations were observed depending on ecotypes, the presence and proportion of these compounds were comparable whether the plants were harvested in nature or cultivated. Suitable and selective modes of application of the biocidal essential oils identified remain to be studied.
