Laboratory studies on the temperature-dependent development of Lacanobia subjuncta were performed at 10 constant temperatures ranging from 10.0°C to 37.5°C. Lower developmental thresholds for eggs, larvae, and pupae were calculated as 6.6, 6.7, and 4.9°C, respectively. Degree-days required to complete a stage were estimated as 75, 476, and 312, for the egg, larval, and pupal stages, respectively. A comparison of the degree-days required to complete immature development under fluctuating field temperatures indicated the laboratory data could be used to predict results in the field. Larval head capsule measurements indicate distinct size ranges for each larval instar with the exception of a slight overlap for fifth and sixth instars.