Technical Abstract: The impact of chinch bug feeding on resistant (‘Prestige’) and susceptible (‘378’) buffalograsses was evaluated through measurement of carbon exchange rate, light and carbon assimilation (A-Ci) curves, chlorophyll a fluorescence, and non-structural carbohydrates. No significant differences in carbon exchange rates were observed between infested and control plants for ‘378’ at 5 and 10 d after chinch bug introduction; however, at 20 d after chinch bug introduction, significant differences between infested and control ‘378’ plants were detected. Carbon exchange rates were similar between ‘Prestige’ infested and control plants at 5, 10, and 20 d after infestation, suggesting that resistant plants can generate energy for recovery from chinch bug feeding. Significant differences in the photochemical efficiency of photosystem II and the apparent photosynthetic electron transport ratio were observed between infested and control ‘378’ plants; whereas, no significant differences in the photochemical efficiency of photosystem II and the electron transport ratio were detected between control and infested ‘Prestige’ plants. Chinch bug-infested ‘378’ and ‘Prestige’ plants consistently had similar or higher levels of non-structural carbohydrates as compared to their respective control plants. These data suggest that both resistant and susceptible buffalograsses increase levels of non-structural carbohydrates in response to chinch bug feeding. However, resistant plants apparently compensate by maintaining photosynthetic rates thereby minimizing tissue injury. Susceptible plants appear unable to maintain compensatory photosynthesis and as a consequence suffer substantially more tissue damage from chinch bug feeding.