Abstract: 【Aim】 Determining the susceptibility of field populations of the whitefly, Bemisia tabaci in Hainan, China to two novel insecticides, cyantraniliprole and flupyradifurone, can help to provide the reference for the rational application of the insecticides and resistance monitoring of its field populations. 【Methods】 The cryptic species identity of field populations of B. tabaci collected from six localities in Hainan Province, southern China in January, 2017 was identified by sequencing of mitochondrial cytochrome oxidase I gene (mtCOI) and PCR-RFLP analysis of mtCOI. The LC₅₀ values of cyantraniliprole and flupyradifurone against these populations were measured using leaf-dip method. 【Results】 Among the six populations, the population from Jiyang, Sanya city was identified as the cryptic species MEAM1, those from Yongfa, Chengmai county and Chongpo, Ledong county were identified as the mixed populations of the cryptic species MEAM1 (<10%) and MED (94.6% and 92.9%, respectively), and the other three were identified as the cryptic species MED. By comparison with the LC₅₀ value of cyantraniliprole against the susceptible population, the population from Shisuo, Ledong county, had developed low-level resistance to cytraniliprole (RR: 5-10), while the other five were susceptible (RR<5). And by comparison with the LC₅₀ values of flupyradifurone, all the six field populations were susceptible (RR<3). 【Conclusion】 Cyantraniliprole and flupyradifurone can be used as candidate insecticides in the control and resistance management of B. tabaci, and more attention should be paid to the resistance development of B. tabaci to cyantraniliprole in the field.

Key words: Bemisia tabaci; cryptic species, mitochondrial cytochrome oxidase I gene, cyantraniliprole, flupyradifurone, susceptibility, Hainan