Screening trials in semi-checked conditions in cages allow to choose the most effective insecticides on Thrips palmi in a short time. The trials herein reported were realized with potted cucumber plants infested with thrips. The mortality percentage among thrips population is counted the first and the sixth days after the spraying. Among the eleven active ingredients tested, only oxamyl, carbofuran, NTN, tokuthion and sulprophos show a good efficacy.