Common pistachio psylla is one of the first-rate pests of pistachios and one of the native pests in pistachio farms in Iran and neighboring countries. The spread and outbreak of this pest requires a review of chemical control to reduce the consumption of pesticides, as well as the identification and use of environmentally friendly non-chemical methods. In this research, the effect of the natural biochar on activating the defense responses of pistachio trees and the feasibility of inducing resistance to control pistachio psylla was investigated by comparing the changes in the density of eggs and nymphs in different leaf levels during two generations. Changes in activity of catalase and peroxidase and non-enzymatic plant defense were investigated. The density of eggs and nymphs affected by the application of biochar decreased significantly from the seventh day onwards compared to the control and reached its lowest level on the twenty-eighth day. In connection with the change in the density of the nymphs, the eta value in the Wilks' Lambda test for the interaction effect of time and treatment was determined as 0.129. The amount of silicon accumulated in the leaves affected by biochar foliar application as an effective physical defense increased by 1.1 times after 48 hours and subsequently by 1.4 times after 14 days compared to the control treatment. Based on the obtained results, the use of biochar can create direct defense and induce resistance of pistachio trees to pistachio psylla by increasing the level of factors inhibiting nutrition and spawning.