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This review aims at better understanding the employment of biocontrol plants in order to enhance the stability of populations of predatory mites in crop systems, with the ultimate goal to reduce pesticide use and to control pest mites on roses. We analyzed if plant species used in a banker plant system influenced the success in terms of quality of the harvested plant and of pest/predator numbers under greenhouse conditions, aiming at using conditions which correspond to the practice of the local producers in Southern France. The main hypothesis was that the presence of different species of biocontrol plants causes the presence of different numbers of predators and pests with a consequent different impact on crop health in a crop-pest-predator system, depending on the plants’functional attributes. Mainly plants with domatia were efficient. They increased the number of predators, stabilized their presence throughout the weeks of experiments, and reduced numbers of spider mites. The function of domatia was analysed through additional experiments which lead to the conclusion that plants with domatia can significantly enhance biological control of the red spider mite, and that especially Viburnum tinusis suited to be employed under the climatic conditions of the Mediterranean area.

[EN] The red palm mite (RPM), Raoiella indica Hirst (Acari: Tenuipalpidae), is an invasive phytophagous mite that was recently introduced into The Americas. The predatory mite Amblyseius largoensis Muma (Acari: Phytoseiidae) has been the only natural enemy consistently found in association with RPM. This study aimed to determine if A. largoensis populations from the Indian Ocean Islands (La Reunion and Mauritius) and the Americas (Brazil, Trinidad and Tobago and the USA) consist a taxonomic unit or a group of cryptic species. First, the morphological variability among the A. largoensis populations from these areas was evaluated through morphometric analyses of 36 morphological traits. Then, their genetic variability and phylogenetic relationships were assessed based on two target DNA fragments: the nuclear Internal Transcribed Spacer and the mithochondrial 12S rRNA. Finally, reproductive compatibility of the populations from La Reunion and Roraima, Brazil was evaluated. Morphometric differences between the A. largoensis specimens from La Reunion Island and the Americas were observed, most of them on the length of the setae. Molecular analysis indicated that the A. largoensis populations from the Indian Ocean Islands and the Americas belong to the same taxonomic entity, although to two well defined genetic groups. Crossings involving the A. largoensis populations from La Reunion Island and Roraima, Brazil revealed complete reproductive compatibility between these populations. Information on the morphometric and genetic variability among studied A. largoensis populations can be further exploited in future studies to follow colonization of Indian Ocean Islands populations in the Americas, in the case of field releases. (C) 2014 Elsevier Inc. All rights reserved., We thank the Agricultural Research Centre for International Development (CIRAD), in special Dr. Serge Quilici, for the logistical support in obtaining the population from La Reunion. We are grateful to Serge Kreiter, Gilberto J. de Moraes, Tatiane Marie Martins Gomes de Castro, Ricardo Adaime da Silva, and Farsan Hosein for their assistance in the sample collection. To Jose Wagner Melo and Daniela Duarte Rezende for the support with SAS statistical analyses. To Bruno de Paiva Rocha and Adilson Werneck for graphical abstract edition. Finally we are grateful to Gilberto J. de Moraes for valuable manuscript review. This research was partially funded by the National Council for Scientific and Technological Development (CNPq), Brazil, call CNPq/SDA/MAPA Call 064/2008. Authors D.N., R.S.M. and M.G.C.G. Jr. also thanks CNPq for research and post-doc fellowships.

L’acarien rouge de la tomate Tetranychus evansi (Acari: Tetranychidae) est considéré comme une espèce invasive à fort impact économique sur les cultures de solanacées. Il a été découvert pour la première fois en 1954 au Brésil, d’où il est probablement originaire. Historiquement, T. evansi a d’abord été signalé en Afrique et plus récemment en Europe et en Asie. L’objectif de cette thèse était de reconstruire les routes de colonisation de T. evansi et de dégager le scénario évolutif décrivant le mieux l’histoire de l’invasion. Nous avons d’abord analysé des échantillons collectés dans son aire actuelle de distribution, à l’aide des séquences d’un fragment du gène codant pour la sous-unité I de la Cytochrome Oxydase (COI) de l’ADN mitochondrial et de la région ITS1-5,8S-ITS2 de l’ADN nucléaire ribosomique. Les données soutiennent l’hypothèse d’une origine sud américaine de cette espèce et ont révélé que des événements d’invasions multiples et cryptiques ont eu lieu lors de la colonisation de l’Europe. L’invasion résulte de deux lignées génétiquement divergentes et originaires de deux régions géographiques distantes au Brésil. Ces deux lignées semblent avoir des potentiels invasifs contrastés. Elles s’hybrident en laboratoire ainsi que dans la nature. Grâce à 16 locus microsatellites que nous avons développés et utilisés comme marqueurs, nous avons déterminé les zones géographiques de cette hybridation. Nous avons également pu estimer des paramètres historiques de l’invasion et confronter différents scénarios d’introduction, par la comparaison de la composition génétique des populations récemment introduites avec celles de l’aire d’origine de T evansi, et par l’utilisation de la méthode d’inférence bayésienne (Approximate Bayesian Computation, ABC). Les résultats ABC contredisent partiellement le scénario d’invasion basé uniquement sur des données historiques. Ils suggèrent que T. evansi serait d’abord arrivé en Europe dans le sud de l'Espagne (en Andalousie) bien avant les signalements historiques. Ainsi, l’Andalousie semble avoir servi de source de colonisation pour des nouvelles zones d’Afrique, d’autres régions méditerranéennes et d’Asie. Les résultats de cette thèse ouvrent des perspectives d’étude visant à comprendre pourquoi certaines populations d‟une espèce allochtone réussissent à s’établir et à envahir un nouvel écosystème., The red tomato spider mite Tetranychus evansi (Acari: Tetranychidae) is regarded as an invasive species having an important economic impact on solanaceous crops. It was first discovered in Brazil in 1954, where it probably originated. Based on historical records, T. evansi was first reported in Africa and more recently in Europe and Asia. This work aims at reconstructing the colonization routes of T. evansi and identifies the scenario that best describes the evolutionary history of the invasion. To do this, we first analyzed samples collected from most parts of the world where the mite is currently known to occur. We used sequence variation of a fragment of the mitochondrial Cytochrome Oxidase (COI) sub-unit I gene and the ITS1-5.8S-ITS2 of the nuclear ribosomal DNA. Our results were consistent with the hypothesis of a South American origin of this species. They also suggested that the invasion of south Europe resulted from multiple cryptic introductions from two genetically divergent lineages originated from two distant geographical regions in Brazil. These two lineages seem to have a differential invasive potential. Despite the high genetic divergence, crosses between mites stemming from the two lineages do occur both in the laboratory and in nature. Second, we used 16 microsatellite loci that we developed for this study and in association with Approximate Bayesian Computation (ABC) methods; we reconstructed the historical events of the cryptic invasion of the pest. ABC results challenge the invasion scenario captured by historical data only. They suggest that T. evansi first arrived to Europe in Southern Spain (Andalusia) long before historic records. Thus, Andalusia seems to have served as a source for colonization of new areas in Africa and other Mediterranean regions. The results obtained in this thesis provide an interesting framework to further study and understand why some populations of an exotic species might become invasive.