Abstract: The demography and leaf consumption of the tea geometrid, Ectropis grisescens Warren (Lepidoptera: Geometridae), were studied on two cultivars of tea, Camellia sinensis (L.) cv. ‘Fuding Dabaicha’ (FDDB) and cv. ‘Rougui’ (RG). The head widths of E. grisescens instars adhered to Dyar’s rule, with no overlap between instars, allowing for accurate estimation of field population stage structure during pest management studies. Leaf consumption increased geometrically with each instar at rates of 3.6335 for FDDB and 3.2048 for RG. The intrinsic rate of increase and finite rate of increase of E. grisescens on FDDB (r = 0.1669 d-1, λ = 1.1817 d-1) were higher than those on RG (r = 0.1482 d-1, λ = 1.1598 d-1). Similarly, the net consumption rate (C0 = 37.5 cm2) and finite consumption rate (ωβ = 4.0185 d-1) of E. grisescens on FDDB were significantly higher than those on RG (C0 = 29.05 cm2 and ωβ = 2.9211 d-1). Given that only young shoots (single bud with two leaves) are manually harvested for high-quality tea production, distinct economical thresholds are required for the harvest and post-harvest seasons. The geometrical ratio of consumption rate could be utilized to simulate the pest damage, yielding results comparable to those derived from detailed daily consumption rate. Integrating demographic parameters, leaf consumption, season-specific economic thresholds, geometrical ratios of leaf consumption rates, and head width data would significantly enhance the integrated pest management program using computer simulation based on the age-stage, two-sex life table.