Abstract:

【Aim】 The rice leaf folder (RLF), Cnaphalocrocis medinalis, as one of the migratory insect pests of rice, can also complete its development on corn. This study aims to determine the influence of host switch on the performance of host populations of C. medinalis. 【Methods】 The RLF corn population (RLF-cp) and rice population (RLF-rp) were fed with their original and switched host plants, respectively, resulting in four treatment combinations: RLF-cp feeding on corn, RLF-cp feeding on rice, RLF-rp feeding on corn and RLF-rp feeding on rice. The age-stage two-sex life tables of the RLF host populations of the four treatment combinations were established, and the performance and life table parameters of these RLF host populations were measured. 【Results】 The developmental duration of immature stage of RLF-rp feeding on rice was the longest (29.2 d), while that of RLF-cp feeding on rice was the shortest (24.8 d). The values of performance indexes (pupal weight, pupation rate, emergence rate, and fecundity), life table parameters (survival rate, maximum fecundity, maximum reproductive value, and immature life expectancy), and population parameters (intrinsic rate of increase, finite rate of increase, and net reproductive rate) of RLF-cp and RLF-rp feeding on corn were the highest while those of RLF-cp feeding on rice were the lowest (except for pupal weight), and those of RLFrp feeding on corn were higher than those of RLF-rp feeding on rice.【Conclusion】 Performance and population growth of the corn population of C. medinalis decrease significantly after host switch, while those of the rice population increase slightly, indicating that corn is more suitable for improving performance and population growth of C. medinalis than rice, which contradicts with the fact that C. medinalis rarely occurs naturally on corn.

Key words: Cnaphalocrocis medinalis, development fitness, corn, rice, host switch, age-stage two-sex life table