Biological control of cereal Aphids with Entomophthorales

Research done in France on Entomophthorales attacking cereal aphids gave published results in very numerous fields: biology, ecology, syste- matics, biochemical characterization of strains, physiology of growth and sporulation, production and formulation of inoculum, measure of infectivity, determination of factors governing the pathogenicity. Under oceanic climate, in western France, Erynia neoaphidis is the most effective and constant natural enemy of cereal aphids. In continental France the effect of Entomophthorales is more irregular but E. neoaphidis and Entomophthora planchoniana can develop spectacular epizootics. In green houses it is possible to permanently establish the disease after spraying an industrially produced inoculum. However the enzootic development of the entomophthorosis is not able to prevent the increase of the aphid populations. Major difficulties are: selection of the best suitable strain for the control strategy, depending on the population level, and obtaining an inoculum physiologically closer to that natural one. When taking into consideration the leading part often played by Entomophthorales in the regulation of aphid populations, further research is needed in these priority areas. (Résumé d'auteur