Response of Bractocera cucurbitae females (Diptera, Tephritidae) to cucurbit host fruit odors.

International audienceBactrocera cucurbitae (Diptera, Tephritidae) is one of the major pest for cucurbits (cucumber, zucchini, melon, etc.) and can cause nearly 90% production losses on Cucurbitaceae crops in La Réunion.The objective of the present study was to improve our knowledge of olfactory stimuli used by females of B. cucurbitae to locate cucurbit host plants. We firstly compared different laboratory devices (a wind tunnel, olfactometers with one or four arms and small test cages) for assessing fly responses to different host plants. In the wind tunnel, females showed no orientated response in the presence of host odours. By contrast, positive response in small test cages and olfactometers was recorded. This allowed us to measure the relative attractiveness of the odours of different wild and cultivated cucurbitaceae for B. cucurbitae females. In parallel, the volatile composition of the odours of fruit and flowers of these different cucurbits was characterised using headspace-solid phase microextraction (SPME)/gas chromatography-mass spectrometry (CG-MS). This study should allow us to assess the host preferences of the Melon fly and eventually identify some powerful kairomonal attractants for this pest

Principaux résultats du projet Biopiper

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Production durable d’extraits naturels biocides de deux Pipéracées à La Réunion

International audienceThe BIOPIPER project is a French Innovation and Partnership project that took place in Reunion Islandfrom 2015 to 2018 with different partners of Research & Development. Its purpose was to producenatural extracts of two Piperaceae (Peperomia borbonensis and Piper borbonense) in a sustainableapproach, for a use in the context of agroecological crop protection. There were 3 general objectives:(1) Synergize the skills of partners with complementary mandates on the use of endemic plants; (2)Design and implement sustainable production of both plant extracts and evaluate their efficacy asbioprotection agents; (3) Disseminate and enhance the obtained results and products. The project wasstructured around four actions. Action 1 made it possible to design, develop and optimize the productionof the two Piperaceae to ensure optimal production of foliar biomass. Action 2 made it possible toproduce and characterize phytochemical extracts of different ecotypes of wild and cultivated plants.Action 3 measured the biocidal efficacy of extracts on various crop pests (bacteria, arthropods) of ageneric nature and of economic importance in Reunion Island and at the French national level. On fruitflies, which are fearsome pests worldwide, LD 50 and LD 95 (lethal doses of 50% and 95% of thepopulation) were measured on five species (Zeugodacus cucurbitae, Bactrocera zonata, Bactroceradorsalis, Ceratitis quilicii and Neoceratitis cyanescens), with essential oil-based extracts. Analysis of theLD 50 results showed differences between plants, ecotypes and types of extracts. LD 50 tests withessential oils were carried out on other economically important pests (Bemisia tabaci, Frankliniellaoccidentalis), a non-pest fly (Drosophila melanogaster). The essential oil of P. borbonensis has alsobeen tested on various temperate pests (Delia radicum, Meligethes aeneus, Psylliodes chrysocephala).A biocidal effect was found on all insects tested with significant variations in sensitivity. Olfactometrictests were also carried out and revealed that the essential oil of P. borbonensis is not repellent. Thisresult is encouraging and makes it possible to consider a targeted application of essential oil via bait inan "attract & kill" approach. Action 4 initiated the process of developing a regulatory folder for thecommercial use of plant or extract production. Finally, the BIOPIPER project has made it possible tocreate an operational and original consortium in partnership in order to screen, for research or servicepurposes, the biocidal activity of extracts from different plants.Le projet BIOPIPER est un projet Casdar (Innovation et partenariat) qui s’est déroulé à La Réunion de2015 à 2018 avec différents partenaires de la Recherche et du Développement. Sa finalité est deproduire durablement des extraits naturels de deux Pipéracées (Peperomia borbonensis et Piperborbonense), en vue de leur utilisation dans le cadre de la Protection agroécologique des cultures. Ondistingue 3 objectifs généraux : (1) Mettre en synergie les compétences de partenaires aux mandatscomplémentaires sur l'utilisation de plantes endémiques comme outils de biocontrôle ; (2) Concevoir etmettre au point la production durable des deux plantes en vue de leur utilisation comme outils debiocontrôle ; (3) Diffuser et valoriser les résultats et produits obtenus. Le projet s’est articulé autour de 4actions. L’action 1 a permis de concevoir, de mettre au point et d’optimiser la production des deuxPipéracées permettant d’assurer une production optimale de biomasse foliaire. L’action 2 a permis deproduire et de caractériser sur le plan phytochimique les extraits de différents écotypes des plantessauvages et cultivées. L’action 3 a mesuré l’efficacité biocide des extraits sur divers bioagresseurs(bactéries, arthropodes) de caractère générique et d’importance économique à La Réunion et àl’échelle nationale. Sur les Mouches des fruits, ravageurs redoutables à l’échelle mondiale, les DL 50 etDL 95 (doses létales de 50 % et 95 % de la population) ont été mesurées sur 5 espèces (Zeugodacuscucurbitae, Bactrocera zonata, Bactrocera dorsalis, Ceratitis quilicii et Neoceratitis cyanescens), avecdes extraits à base d’huile essentielle. L’analyse des résultats des DL 50 montre des différences entreles plantes, les écotypes et les types d’extraits. Les tests de DL 50 avec les huiles essentielles ont étéconduits sur d’autres ravageurs d’importance économique (Bemisia tabaci, individus issus d’élevage ;Frankliniella occidentalis, individus prélevés en culture de poivron sous serre), une drosophile(Drosophila melanogaster, individus issus d’élevage). L’huile essentielle de P. borbonense a égalementété testée sur différents ravageurs des légumes métropolitains (la Mouche du chou, Delia radicum, leméligèthe Meligethes aeneus et l’altise d’hiver, Psylliodes chrysocephala). Un effet biocide a été trouvésur tous les insectes testés avec des variations importantes de sensibilité. Des tests olfactométriquesont également été réalisés et ont révélé que l’huile essentielle de P. borbonense n’est pas répulsive. Cerésultat est encourageant et permet d’envisager une application ciblée du produit toxique via lanourriture ou les sites de nutrition du ravageur (approche « attract & kill »). L’action 4 a initié leprocessus visant à constituer un dossier réglementaire en vue de l’utilisation commerciale de laproduction des plantes ou des extraits. Le projet BIOPIPER a permis la création d’un dispositif enpartenariat opérationnel et original, permettant de screener, à des fins de recherches ou de prestationsde service, l’activité biocide d’extraits de différentes plantes

Sustainable production of natural biocidal extracts from two Piperaceae in Reunion Island

The Biopiper project is a French Innovation and Partnership project that took place in Reunion Island from 2015 to 2018. Its purpose was to produce natural extracts of two Piperaceae (Peperomia borbonensisand Piper borbonense) in a sustainable approach, for a use in the context of agroecological crop protection. There were 3 general objectives: (1) Synergize the skills of partners withcomplementary mandates on the use of endemic plants; (2) Design and implement sustainable production of both plant extracts and evaluate their efficacy as biocontrol agents; (3) Disseminate and enhance theobtained results and products. The project partners were: Association Réunionnaise pour la Modernisation de l'Economie Fruitière, Légumière et Horticole (ARMEFLHOR); Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD); Institut Technique de l'Agriculture Biologique(ITAB); Plant Advanced Technologies (PAT); Société Horticole de Bassin Plat (SHBP); Université de Rennes 1; Université de La Réunion. The project was structured around fouractions. Action 1 made it possible to design, develop and optimise the productionof the two Piperaceae to ensure optimal production of foliar biomass. Action 2 made it possible to produce and characterize phytochemical extracts of different ecotypes of wild and cultivated plants. Action 3 measured the biocidal efficacy of extracts on various crop pests (bacteria, arthropods) of a generic nature and of economic importance in Reunion Island and at the French national level. On fruit flies, which are formidable pests worldwide, LD 50 and LD 95 (lethal doses of 50% and 95% of the population) were measured on fivespecies (Zeugodacus cucurbitae, Bactrocera zonata, Bactrocera dorsalis, Ceratitis quiliciiand Neoceratitis cyanescens), with essential oil-based extracts. Analysis of the LD 50 results showed differences between plants, ecotypes and types of extracts. LD 50 tests with essential oils were carried out on other economically important pests (Bemisia tabaci, Frankliniella occidentalis), a non-pest fly (Drosophila melanogaster). The essential oil of P. borbonensishas also been tested onvarious Brassicaceae pests (Delia radicum, Meligethes aeneus, Psylliodes chrysocephala). A biocidal effect was found on all insects tested with significant variations in sensitivity. Olfactometric tests were also carried out and revealed that the essential oil of P. borbonensisis not repellent. This result is encouraging and makes it possible to consider a targeted application of essential oil via bait in an "attract & kill" approach.Action 4 initiated the process of developing a regulatory folder for the commercial use of plant or extract production. Finally, the Biopiper project has made it possible to create an operational and original consortium in partnership in order to screen, for research or service purposes, the biocidal activity of extracts fromdifferent plant