Insects and plants have been living and relationship together for more million years. Cucurbitaceae and Solanaceae families were esteemed as important vegetable production in Egypt and were infested by numerous piercing-sucking pests. Recently, climatic changes led to changes in the distribution of these pests. Therefore, the diversity of Bemisia tabaci, Aphis gossypii & Myzus persicae, Empoasca decipiens and Tetranychus urticae on Solanaceae and Cucurbitaceae crops was studied during two summer seasons of 2022 and 2023 years. The obtained results show a susceptible and low resistance of whitefly and spider mite infestations, while, susceptible, moderate and low resistance were recorded with aphid and leafhopper infestations of tested hosts. Data emphasized that B. tabaci and T. urticae were the more dominant species infesting all plants. The tested piercing-sucking pests were recorded 1-3 peaks, concentrating through April-May during the two tested seasons. Data showed that the increasing of B. tabaci and T. urticae populations led to a decrease in GA3, IAA and KIN contents, and an increase in ABA contents, contrariwise, the reverse direction was found with aphids and E. decipiens populations. Moreover, a negative relationship was recorded between phenoloxidase and all tested pests except whitefly was detected a positive effect. A positive relation was reported between phytochemical components and these pests except spider mite was negative. Finally, these results offer useful and appealingly data to point out herein that the infestation rate of piercing-sucking insects must refer to the resistance degree of each cultivar to help in putting the IPM management strategy in the control programs of these pests