Les principaux auxiliaires en viticulture : description, écologie, biologie. Préambule

Au sein des écosystèmes, les populationsd’insectes sont limitées par un complexed’ennemis naturels, qui exercent ainsi uncontrôle spontané et préviennent généralementleurs pullulations. Ces auxiliairespeuvent consommer les oeufs, larves,nymphes ou adultes d’autres arthropodes.Les complexes associés, appelésaussi réseaux trophiques, peuvent êtretrès diversifiés. La figure 2.1 fait ainsiapparaître le complexe associé à Parthenolecaniumcorni et les relations entre lesparasitoïdes

A new species of Eurytoma (Hymenoptera: Eurytomidae) attacking Quadrastichus spp. (Hymenoptera: Eulophidae) galling Erythrina spp. (Fabaceae), with a summary of African Eurytoma biology and species checklist

Eurytoma erythrinae Gates and Delvare, new species, is described and illustrated. This species was reared from fieldcollected galls on Erythrina spp. (Fabaceae) induced by Quadrastichus spp. (Hymenoptera: Eulophidae), in Tanzania, Ghana, and South Africa. It is compared with very similar African species, Eurytoma radicicola Risbec. Afrotropical species classified in Eurytoma are reviewed and twenty-seven new combinations are proposed: Aximopsis acaciacola (Hedqvist) comb. n., A. caryedocida (Rasplus) comb. n., A. lamtoensis (Rasplus) comb. n., A. mateui (Hedqvist) comb. n., A. mimosarum (Rasplus) comb. n., A. obocki (Risbec) comb. n., A. oryzivora (Delvare) comb. n., A. saharensis (Hedqvist) comb. n., A. senegalensis (Risbec) comb. n., A. tropicana (Risbec) comb. n., Bruchophagus conapionis (Rasplus) comb. n., Fronsoma ellenbergeri (Risbec) comb. n., Gibsonoma amborasahae (Risbec) comb. n., G. aphloiae (Risbec) comb. n., G. bararakae (Risbec) comb. n., G. eugeniae (Risbec) comb. n., G. mandrakae (Risbec) comb. n., G. pauliani (Risbec) comb. n., G. plectroniae (Risbec) comb. n., G. tavolae (Risbec) comb. n., Philolema arachnovora (Hesse) comb. n., P. arnoldi (Waterston) comb. n., P. bambeyi (Risbec) comb. n., P. braconidis (Ferrière) comb. n., and P. syleptae (Ferri_re) comb. n., Phylloxeroxenus cressoni (Howard) comb. n., and Sycophila plectroniae (Risbec) comb. n. Lectotypes are designated for ten species: Eurytoma perineti Risbec, Risbec, E. toddaliae Risbec, Gibsonoma amborasahae (Risbec), G. aphloiae (Risbec), G. eugeniae (Risbec), G. mandrakae (Risbec), G. pauliani (Risbec), G. tavolae (Risbec), and P. bambeyi (Risbec). We also provide a checklist of Afrotropical species that are or were classified in Eurytoma and tabulate the known host/associations of these species with references

Numerical solution of Cauchy problems in linear elasticity in axisymmetric situations

International audienceAn iterative method for solving axisymmetric Cauchy problems in linear elasticity is presented. This kind of problem consists in recovering missing displacements and forces data on one part of a domain boundary from the knowledge of overspecified displacements and forces data on another part of this boundary. Numerical simulations using the finite element method highlight the algorithm's efficiency, accuracy and robustness to noisy data as well as its ability to deblur noisy data. An application of the inverse technique to the identification of a friction coefficient is also presented