Thermal stress in living organisms causes an imbalance between the processes of creating and neutralizing reactive oxygen species (ROS). The work aims to explain changes in the aphid-host plant interaction due to an increase in temperature. Tests were carried out at three constant temperatures (20, 25, or 28 °C). Firstly, changes in development of were determined. Secondly, the activity of enzymatic markers (superoxide dismutase (SOD), catalase (CAT), glutathione -transferase (GST), β-glucosidase, polyphenol oxidase (PPO), and peroxidase (POD)) in aphid tissues and host plant were analyzed at all temperatures. An increase in temperature to 28 °C had a negative effect on the biology of by shortening the period of reproduction and longevity, thus reducing the demographic parameters and fecundity. Two stages of the aphid's defensive response to short-term (24-96 h) and long-term (2 weeks) thermal stress were observed. Aphid defense responses varied considerably with temperature and were highest at 28 °C. In turn, for the plants, which were exposed to both abiotic stress caused by elevated temperature and biotic stress caused by aphid feeding, their enzymatic defense was more effective at 20 °C, when enzyme activities at their highest were observed.
