[Objectives]  To explore whether the feeding of Henosepilachna pusillanima adults is affected by applying citrulline, one of major components of cucurbit phloem sap. [Methods]  No-choice and triple-choice assays were performed using leaf discs from leaves of Cucurbita moschata Duchesne. Abaxial surfaces of the leaf discs were sprayed with either deionized water (control), or 20 mmol∙L^－1 or 60 mmol∙L^－1citrulline, respectively, and the amount of leaf area consumed by individual mated adult females and males that had been starved for 24 hours was measured. The percentage of leaf area consumed by individuals from each treatment group in the choice assays was also calculated. [Results]  Females consumed significantly more leaf material than males in all three treatments in the no-choice assays. Treatment with 20 mmol∙L^－1 or 60 mmol∙L^－1 of citrulline significantly reduced the amount of leaf consumed by males to 36.88% and 49.33%, respectively, of the 5.32 cm² consumed of by the control group. Similarly, treatment with 20 mmol∙L^-1 or 60 mmol∙L^-1 citrulline reduced consumption by females to 42.08% and 53.36%, respectively, of the 7.60 cm² leaf area consumed by the control group. There were, however, no significant differences between the two citrulline treatment groups in the leaf area consumed by either males or females. In choice assays, both males and females exhibited a strong preference for control leaf discs over those treated with citrulline.[Conclusion]  At certain concentrations, citrulline inhibits feeding by H. pusillanima adults, which provides new evidence of the mechanisms that underlie feeding behavior in this species.