An improved artificial diet for Ectropis obliqua Prout (Lepidoptera: Geometridae) is described. Mean growth parameters of insects fed the diet demonstrated a higher level of pupation, a greater pupal weight, and a higher level of emergence from pupation as compared to those fed a commonly used general purpose diet. The feeding effect is similar to a diet containing tea powder. This improved artificial diet is suitable for E. obliqua used in research and allows for the addition of any monomeric compounds to assess impacts on E. obliqua growth or other parameters.