The avocado (Persea americana Mill.) is the fourth most important tropical fruit in the world, with relevance in international markets due to its benefits for human health. The use of silicon (Si) can minimize the adverse effects of abiotic stresses, increase resistance against arthropod pests, and promote growth in fruit crops. Considering the beneficial effect of Si reported in various crops and the limited information on its effect on avocado, this study investigated the effects of the application of two sources of Si (acidic and basic) on the physiology, growth, and population dynamics of arthropod pests of 'Hass' avocado plants. Three experiments were carried out with three different plant development stages: seedlings (Fresno, Tolima), young trees (Bituima, Cundinamarca), and adult trees (El Tablazo, Tolima). The treatments were as follows: 1) plants without Si application (control), 2) plants with foliar application of acidic Si, 3) plants with foliar application of basic Si, 4) plants with foliar treatment with acidic Si and pyrethrins, and 5) plants with foliar treatment with basic Si and pyrethrins. Foliar applications of Si caused less accumulation of adult arthropod pests such as Heliothrips haemorrhoidalis, Monalonion velezangeli, Polyphagotarsonemus latus, Bombacoccus aguacatae, Paraleyrodes sp., and Oligonychus yothersi compared to the control treatment. Foliar applications with the two Si sources also favored plant height and shoot length. Si caused a positive effect on leaf stomatal conductance, chlorophyll content, and plant hydraulic conductivity at the end of the three experiments. The results obtained allow us to conclude that the use of Si can be considered a complementary tool in the management of some arthropod pests in avocado. Additionally, Si may help in the management of avocado crops by improving the physiological response in plants at different development stages.