The study conducted on the population dynamics of the olive psyllid Euphyllura olivina, (Costa, 1839), on the variety Chemlal in the oases of Boussaâda, during the first half of the year 2021, showed that the first numbers of the different biological stages of the insect are recorded in mid-March 2021, where all directions of the tree are infested while the northern and western directions are the most exposed to attacks of the pest. The first numbers of adults of E. olivina are recorded in mid-April, while mortality according to the directions of the tree is recorded on all cardinal directions of the tree, with a rate of about 39% on the northern direction.