The fall armyworm, Spodoptera frugiperda is a major agricultural pest in China, and has migrated from its continuous breeding area to other parts of China. In our study, the biological behaviors of S. frugiperda fed on maize, wheat, barley, faba beans, and soya beans were evaluated in a growth chamber. Results indicated that maize-fed S. frugiperda larvae performed well, as evidenced by shorter larva-adult periods, adult pre-oviposition period (APOP), total pre-oviposition period (TPOP), and generation time (T), and a higher survival rate, intrinsic (r) and finite (λ) rate of increase, and net reproductive rate (R_o), However, S. frugiperda larvae performed weakly when fed barley and faba bean plants, as indicated by lower survival rates, r, and λ, and longer pre-adult period, TPOP, and T. A heavier pupal weight of both sexes was recorded on faba beans (0.202 g) and a lighter weight on barley (0.169 g). Fecundity was higher when fed faba beans and maize, and lower when fed wheat and barley. Thus, maize was the most optimal and barley was the least optimal host plant, followed by faba beans, for S. frugiperda larvae growth and development. This study enhances our knowledge of S. frugiperda in these host plants and can help in the design of management approaches.

In order to clarify the migration route and the source of white-backed planthopper (WBPH) (Sogatella furcifera) between Myanmar and Yunnan Province, China, we collected six populations throughout Myanmar and five populations around the border areas in Yunnan Province, China. A total of 790 base pairs in the mtDNA COI genes from 416 individuals were obtained. A total of 43 haplotypes were identified, among which 37 were unique haplotypes, and the remaining 6 were shared among different populations. Two common shared haplotypes (H_1 and H_2) had a widespread distribution in all populations and accounted for 88.8% of the total haplotype frequency, suggesting a high-level gene flow among the Myanmar and Yunnan populations. Bayesian skyline plot (BSP) analysis results indicated that the effective population size of WBPH expanded between about 10,000 and 7000 years ago, and S. furcifera might follow the post-LGM (Last Glacial Maximum) expansion pattern. Based on the total migrant (N_em) value, it can be deduced that north and northeast Myanmar were the primary migration sources for WBPH populations in the southwest and south Yunnan regions. This study aims to contribute to the sustainable regional management of this important rice pest and provide new insights into the genetic diversity of WBPH in Southeast Asia.

The fall armyworm (FAW) is an invasive pest that has been rapidly spreading across China since its detection in Yunnan province in January 2019. Although sugarcane and sorghum have been reported as hosts, their effects on FAW’s population growth and life table parameters have not been examined in China. Our research shows that FAW’s development and life table metrics vary significantly when reared on sorghum, sugarcane, and maize. Notably, the preadult stage, adult preoviposition period, and total preoviposition period of FAW were markedly longer on sugarcane and sorghum compared to maize. FAW reared on these two crops also exhibited reduced survival rates, pupal weight, fecundity, and lower female-to-male ratios. The study highlights that FAW had lower population growth rates, reproductive rates, and longer generation times on sugarcane and sorghum compared to maize. The consumption index and digestibility index were higher on maize, while conversion efficiency and growth rate were greater on sorghum. Although maize is the most favorable host, FAW can still survive and reproduce on sugarcane and sorghum during the nongrowing season, posing a risk to economically important crops in China. Despite being less favorable for population growth, sugarcane and sorghum still support FAW development and spread. Therefore, enhanced surveillance and early warning measures for sugarcane and sorghum are recommended to monitor FAW population dynamics and mitigate its potential impact on primary host plants.