Immunity in solanacies against doryphorus | L'immunité chez les solanacées à l‘égard du doryphore

In the study of the forces of nature which can be used, if necessary, to reduce the damage of the Colorado beetle ( Leptinotarsa ​​decemlineata Say), three main lines of research were to be followed. They were approached in 1927, when it appears that one could no longer extinguish the outbreak of the insect discovered in 1924 in southwestern France. These three paths concerned: - the action on the Colorado beetle of a-biotic factors (climate and sometimes soil); - the action on the Colorado beetle of natural enemies, entomophagous and entomophytes; - finally, the action on the insect of certain factors of immunity that may be presented by the plants it attacks or could attack. Following the first orientation, a number of "passive" uses have taken place. In particular they relate to the use of the damaging action of the climate in the spring resulting from the fact that insect and potatoes do not have the same lower thresholds of thermal requirements, so can it be used for some phase shifts can give very marked effects. They allow the development of potato early crops, practically without chemical treatments, especially when care is taken in the area where they are established, the absence of seasonal potato crops and eggplant plantations ( Solanum melongena L.). In the field of biological control in the usual restricted sense of the term, the first studies - basic studies - were carried out mainly from 1928 to 1939. The work will be taken up by the International Commission for Biological Control, Commission recently created and which involves a working group on the natural enemies of the Colorado beetle chaired by Dr. F ranz of Darmstadt. This group held its first meeting this winter, in Gembloux, and set two main orientations for its efforts: to have the minimum of action of insecticide treatments on the game of natural biological control; if possible, to have in Europe in addition to our native entomophages, other species coming from the country of origin of the Colorado beetle. The third route included immunology studies and their use in researching crop plants, if possible, which were not very susceptible to attack or even resistant.