This study was carried out to study the effect of treated Duranta seedlings Duranta sp. fam: Araliaceae by different concentrations of Triacontanol hormone (TRIA) on the infestation by Duranta aphid, Aphis durantae Theobald (Homoptera: Aphididae) and Tetranychus urticae Koch (Fam: Tetranychidae) under glasshouses conditions. This study was carried out at two locations (Governorates), El-Orman Garden (Giza Governorate) and International Garden (Alexandria Governorate) throughout 2018 season.
         Three treatments (concentrations) of Triacontanol hormone were done in both the two locations, small concentration (25ppm), medium concentration (45ppm) and high concentration (65ppm), beside fourth treatment which did not treat with any hormone (control). Duranta plants which treated with a small concentration of (TRIA) (25ppm) were lower infestation by both A. durantae and T. urticae comparing to control. Duranta plants which treated with a medium concentration of (TRIA) (45ppm) were had no significant effect on the infestation by the two pests compared to control. On the other hand, duranta plants which treated with a high concentration of (TRIA) (65ppm) were higher infestation by both the two pests comparing to control.
         From obtained results we can recommend using Triacontanol hormone (TRIA) on the Integrated Pest Management (I.P.M) programs by doses showed at this study.