Fall armyworm, Spodoprera frugiperda (Smith) larvae were reared in the laboratory on foliage on 4 varieties of bermudagrass, (“Alicia”, “Callie”, “Coastal”, and common), at 3 constant temperatures (20°, 25° and 30°C). Studies were designed to measure the effect of these 4 bermudagrass varieties and temperature on the biology of the insect. Differences in length of larval period, pupal weight, and length of pupal period, between grasses, were temperature and sometimes sex dependent. No significant differences were observed between grasses for egg production; however, significant differences were observed between temperatures. Larvae and pupae developed most rapidly at 30°C. Egg production was maximal at 25°C.