Survival of Fall Armyworm, Spodoptera frugiperda, (Lepidoptera: Noctuidae) Exposed to Cold Temperatures

All life stages of seasonally acclimatized fall armyworms, Spodoptera frugiperda (J. E. Smith), were subjected to temperatures of 0, -2.5, -5, -7.5, and -10@*C for 3 h in a temperature cabinet. The adult stage was most susceptible to cold temperatures, with only 26% of the moths surviving at -5@*C and no survival at the colder temperatures. The egg was the most tolerant stage, with 30% survival at -10@*C. Fall armyworm pheromone traps located near Belle Glade, Fla. were checked weekly during the winters of 1985-86 and 1986-87. Seven nights of subfreezing temperatures during those two winters resulted in little or no adult mortality. Our study, which included lethal temperature data, microclimate data, and field population data, shows that extreme low temperatures are not important mortality factors on fall armyworm populations in southern Florida.