The work which sarted in 1979 progresses in a biennial cycle in spite of the annual character of the selected species. To obtain seeds it is necessary to use in vitro culture as crop establishment has to coïncide with the activity of the pest. F2 or F3 stages occur in even years, whereas F3 plants occur in odd years and are checked in this year. An examination of the mean number of eggs laid per plant shows that in 1988 for the first time significant difference between an F3 line and the control variety were obtained. Some lines have evolved significantly towards relative resistance without being different from the control. The observed individual variability should permit further improvement in the level of resistance.