Biology and Life-Table Parameters of Fall Armyworm, Spodoptera frugiperda on Three Maize Cultivars Grown in Thailand

Abstract Fall armyworm, Spodoptera frugiperda has become a new invasive species in Thailand that mainly affects maize. There has been limited research on the baseline biological aspects of this insect under controlled conditions. Our objective was to detail the biological parameters of S. frugiperda reared on maize (Zea mays L.) cultivars, field maize, sweet maize and waxy maize under controlled conditions at 30 ± 2°C, 55 ± 5% RH and a 12-hour photoperiod. Results suggest that larvae develop through six instars on all the maize cultivars. Significant effects (P < 0.05) of the host plant were found in the duration of larval stage 10.83 ± 0.14, 11.15 ± 0.15 and 11.28 ± 0.05 days when fed with sweet maize, waxy maize and field maize, respectively. More than 70.5% of them transformed into the pupal stage. The life cycle duration lasted 28.11 ± 0.40 days (field maize), 27.16 ± 0.37 days (sweet maize) and 28.41 ± 0.34 days (waxy maize). Significant differences among host plants were not observed for the different development durations. S. frugiperda exhibited a type I survivorship curve. The highest values of net reproductive rate, R0 (220.41 ± 5.88), innate capacity of increase, rc (0.23 ± 0.001) and finite rate of increase, λ (1.25 ± 0.002) obtained on sweet maize, were not statistically different from other cultivars. The mean generation time (Tc) was significantly different among the 3 maize cultivars, ranging from 26.36 ± 0.43 days on waxy maize to 23.80 ± 0.24 days on sweet maize. Information presented here should greatly expand the understanding of S. frugiperda biology; this understanding can be used to improve the efficiency of management techniques for this critical crop pest. Keywords: Invasive species, Maize pest, Biological cycle, Reproductive rate, Population growth