Comparison of the activity of certain pathogens of the cockchafer Melolontha melolontha in plots of natural meadowland

Two systems of plots of 16 m2 established in natural meadowlands in the Department of Sarthe were used for a study of infecting populations of cockchafer larvae with 5 diseases: the milky disease caused by Bacillus popilliae “melolontha,” the rickettsiosis caused by Rickettsiella melolonthae, the virosis caused by Vagoiavirus (= Entomopoxvirus) melolonthae, the coccidiosis caused by Adelina melolonthae, and the mycosis caused by Beauveria tenella. The principal ecopathological characters of these diseases have already been determined in the laboratory.