We investigated developmental characteristic of life cycle of the lawn cutworm, Spodoptera depravata (Lepidoptera: Noctuidae), which is one of the most economically damaging pests to grasses. For larval culture the turfgrass, Zoysia japonica (Poales: Poaceae), was provided at 25℃ and 60 ± 5% humidity. Developmental period of each stage was as follows: 4.11 ± 0.19 days for eggs, 25.17 ± 3.02 for larvae, 8.80 ± 0.28 for pupae and 7.57 ± 0.95 for adults. Larvae was grown to 7th instar, unlike pre-existing data, which indicated the final age as the 6th instar. Body length of larvae changed on average from 2.772 mm immediately after hatching to 2.3 cm at 7th instar and head capsule width changed on average from 0.423 mm at 1st instar to 2.82 mm at 7th instar. Pre-period of eggs deposition was 2 days, oviposition period was 4.6 days, average fecundity per female was about 419 eggs, and hatching rate was about 83%.

We investigated primary ecological characters, such as life cycle and morphology of the lawn cutworm, Spodoptera depravata (Lepidoptera: Noctuidae), which is one of the most economically damaging pests to grasses. For larval culture the turfgrass, Zoysia japonica, was provided as a feed source at 25℃ and 60±5% humidity. Development period of each stage was as follows: 4.11±0.19 days for eggs, 25.17±3.02 for larvae, 8.80±0.28 for pupae and 7.57±0.95 for adults. Larval stages continued to 7th instar and this result contrasts to pre-existing data, which indicate 6th instar in S. depravata. Developmental period of each instar of S. depravata ranged from the minimum of 2.1 days to the maximum of 4.81 days, with the 7th instar longest. Correlation analysis between body length and head capsule width of each instar showed a significant correlation between the two measures. Pupal colors were changed from the light brown and green right after pupation to dark brown as pupal cuticle hardens. Wing length of adults in both sexes was similar, but forewing of male had obvious outer line and eyespot with dark gray-brown background, whereas that of female had less obvious in these characters, with light gray-brown background. Pre-period of eggs deposition was 2 days, oviposition period was 4.6 days, average fecundity per female was about 419 eggs, and rate of hatching was about 83%.