Memoria para optar al Título Profesional de Ingeniero Agrónomo Mención: Sanidad Vegetal / The effect of two formulations of imidacloprid, Confidor Forte 200 SL and Winner®, to control Pseudococcus longispinus (Targioni y Tozzetti) and their impact on Neoseiulus californicus (McGregor) in avocado trees was studied during the 2004 season. Treatments were applied in two avocado commercials orchards, one in Isla de Maipo (Metropolitan Region) on 5 year-old trees, and the other in Lliu-lliu (5th Region) on 11 year-old trees. The products were applied to the foliage with a hand spray gun, or localized to the bark of the trunk with a pistol sprayer, or painting a circle around it with a paintbrush.