Inappropriate insecticide application can lead to harmful effects on cultivated plants, causing disruptions in physiological and enzymatic processes that ultimately impact overall yield and result in the presence of pesticide residues. During 2020, the influence of six insecticides (cyantraniliprole, chlorantraniliprole, spinetoram, indoxacarb, deltamethrin, pyriproxyfen, and acetamiprid) on the chlorophyll, carotenoids, hydrogen-peroxide, and malondialdehyde in peach leaves was assessed. Insecticides were applied in the recommended dose for the control of Grapholita molesta, the main peach pest. The leaves were sampled three and seven days after the treatment, and laboratory analysis of physiological and biochemical parameters was performed by spectrophotometer on the same day. The obtained results indicate that after three days, chlorophyll (a+b) content decreased (6.9-43.1%), while the carotenoid content increased (3.9-27.4%), compared to the control. After seven days, chlorophyll (a+b) decreased from 7.3 to 38.4%, and also carotenoid in the treatments with deltamethrin, pyriproxyfen, and acetamiprid (3.2-30.6%), while the other treatments showed an increase (3.2-41.9%). The highest increase in hydrogen-peroxide concentration was obtained in the treatments with spinetoram and deltamethrin (50-85%) after seven days. The concentration of malondialdehyde in all samples was higher after three days (31-39.3 nmol/g) compared to the concentration seven days after treatment (30-22.5 nmol/g). Results showed different biochemical reactions in peach leaves due to the applied insecticides. Insecticides caused significant changes in the pigment content; however, these changes were transient, so it is assumed that they do not remarkably affect the plant.