Abstract: 【Aim】 This study aims to clarify the feeding and oviposition preference and fitness of the fall armyworm, Spodoptera frugiperda, on host plants rice and maize and then to analyze its damage risk to rice. 【Methods】 The feeding and oviposition preference of S. frugiperda were tested by free choice method. The development, survival rate and fecundity of S. frugiperda fed on maize and rice seedlings were investigated, and the fitness of S. frugiperda on rice was evaluated by the population growth trend index (I). 【Results】 There were significant differences in the feeding and oviposition preference of S. frugiperda to rice and maize. The choice rate of larvae to feed on maize increased with time during 2-48 h post infestation, while that on rice decreased with time. At 48 h post infestation, the choice rates of the 2nd and 4th instar larvae to feed on maize were 93.06% and 59.72%, respectively, which were 66.95 and 21.48 times as high as those to rice. In terms of oviposition preference, the number of eggs laid on maize was 8.64 times as high as that on rice after a free oviposition period of 6 d. The individuals of S. frugiperda fed on rice seedlings had longer developmental duration, lower egg hatching rate, larval growth rate, pupation rate, adult emergence rate and proportion of females, shorter female longevity and less eggs laid per female as compared to those fed on maize seedlings. The population growth trend index (I) of S. frugiperda fed on maize seedlings was 165.93, and the relative fitness of S. frugiperda on rice seedlings was 0.21. 【Conclusion】 S. frugiperda prefers to feed and lay eggs on maize rather than on rice, and shows a higher fitness on maize. Rice is a non.preferable host to S. frugiperda that has invaded China, but it can feed on rice seedlings to grow and develop normally and finish its life cycle. The results suggest that S. frugiperda may become a potential threat to rice production when it has a high population density and its preferable host plants are absent.

Key words: Spodoptera frugiperda, host plant, feeding preference, oviposition preference, development, fecundity, fitness