A series of insecticidal treatment schedules involving different numbers and timings of thiodan sprays were devised to obtain a gradient in the okra leafhopper(Amrasca biguttula biguttulaIshida) population, in order to evaluate the yield‐infestation (population) relationship and determine the economic injury level (EIL). The yield infestation relationship was best explained by the linear form of equation, (Y = 64.99 ‐ 0.8525 X), as compared to the log linear and quadratic forms. A mean EIL value of 4.66 leafhoppers per plant was calculated for four Insecticides from the yield infestation relationship and the gain thresholds, based on the costs of protection and the price of okra.