Lutte biologique par augmentation à l’aide d’arthropodes entomophages contre les arthropodes phytophages

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Augmentative biological control using entomophagous arthropods

International audienceAugmentative biological control is based on the repeated introduction of mass-produced biological control agents as predators or parasitoids with the aim of temporarily controlling or even eradicating pest populations. The different augmentative strategies form a continuum ranging from preventive releases of small numbers of natural enemies prior to the arrival of the pests for a delayed impact (inoculation) to intense, short-term mass releases for a quick and drastic impact on the pest population (inundation). These strategies may also be combined with practices that aim to favour the individual fitness and/or the population establishment of the biological control agents. After briefly reviewing the history of such practices, this chapter explores different challenges currently faced by augmentative biological control linked to the production of biocontrol agents, the underlying business models and the potential existence of non-target effects. Finally, different ways to improve augmentative biological control are investigated, from better selection of biocontrol agent strains to innovations in rearing conditions or supplementation of resources to support the introduced natural enemies. The need to better understand the population dynamics at play or the possible combination of augmentative biological control with entomovectoring techniques are also discussed

Four Amino Acids of an Insect Densovirus Capsid Determine Midgut Tropism and Virulence

International audienceDensoviruses are insect parvoviruses that are orally infectious for Lepidoptera. To assess the mechanisms underlying their specificity and their virulence, we investigated the role of eight candidate residues in the densovirus capsid. We showed that the substitutions of four amino acids were associated with decreased virulence due to a decreased ability to cross the host midgut epithelium, without an effect on viral replication in other tissues

The French touch in entomological biology : synthesis of the "16th Colloque Biologie de l'Insecte"

Pas de résumé, pas de mots clés,pas de doi.International audience

Les densovirus : une « massive attaque » chez les arthropodes

Densoviruses (DVs) are parvoviruses of arthropods and causative agents of natural epizootics in insects and crustaceans populations. Structurally simple, these small DNA viruses, display a large diversity of genomic sequences, structures and organizations. Such diversity, together with the diversity of their invertebrate hosts, from shrimps to mosquitoes and recently including sea stars, suggests that DVs are largely unknown and ubiquitous in the environment. Densoviruses are considered as a model of choice to study virus-host interactions and their evolution at different scales, from individuals to populations. This review summarizes the knowledge on densovirus biology obtained through mechanistic and global approaches. Finally, the potential use of these viruses as biological control agents against insect pests and disease-vectors are exposed.Les densovirus (DV) sont des parvovirus d’arthropodes responsables d’épizooties chez les insectes et les crustacés. Structurellement simples, ces petits virus à ADN présentent une grande diversité de séquences et d’organisations génomiques, diversité probablement sous-estimée au regard des récentes découvertes de ces virus dans des hôtes inattendus. Les densovirus représentent un modèle de choix pour étudier à différentes échelles les interactions virus-hôtes et leurs évolutions. Nous proposons de revisiter les connaissances fondamentales sur les densovirus qui ont essentiellement été établies par des approches mécanistiques et envisageons les nouvelles perspectives d’études permises par des approches plus globales. Pour conclure, nous décrivons les applications possibles de ces virus comme outils biologiques, notamment pour le contrôle de populations d’insectes dits « nuisibles »

Vers une gestion des gènes de résistances comme des biens communs

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