JIA-2019-11

2574 WANG Ran et al. Journal of Integrative Agriculture 2019, 18(11): 2571–2578 in SX over 13 generations (F 2 to F 15 ) with no selection. LC 50 of SX-R and SX was compared at F 15 to establish patterns of cross-resistance (Table 2). Both SX-R and SX strains showed minimal resistance (<3.0-fold) to all tested insecticides except cyantraniliprole, which means that SX-R had no cross-resistance to imidacloprid, thiamethoxam, abamectin, sulfoxaflor, or bifenthrin. 3.3. Inheritance of cyantraniliprole resistance The concentration–response lines of parental strains and their F 1 progenies from reciprocal crosses are summarized in Table 3. In the SX-R strain, the LC 50 values of the F 1 progenies fromMED-S ♂×SX-R♀ (F 1A progeny) did not differ significantly from the LC 50 values of the F 1 progenies from MED-S ♀×SX-R ♂ (F 1B progeny), and the results showed that SX-R had autosomal inheritance. The D values of F 1A and F 1B derived from SX-R were 0.78 and 0.77, respectively. This implied that the inheritance of SX-R was incompletely dominant (0< D <1). 3.4. Synergism on cyantraniliprole resistance The synergistic effects of PBO, DEM, and TPP to cyantraniliprole in the MED-S strain and the SX-R strain are shown in Table 4. An obvious synergistic effect of PBO to cyantraniliprole was detected in the SX-R strain with synergistic ratio (SR) 4.6 and DEM and TPP had no significant synergism in the SX-R strain (SR=1.0 and 1.1, respectively). These results meant that mixed-function oxidases were probably involved in cyantraniliprole resistance in the SX-R strain. 4. Discussion Understanding levels of resistance, inheritance, cross- resistance patterns, and mechanisms of resistance to one novel insecticide is very important for formulating sustainable strategies for pest management in the field. Several reports concerning the susceptible baseline of B. tabaci to cyantraniliprole have been published recently (Li et al. 2012; Caballero et al. 2013; Grávalos et al. 2015), and our previous work indicated that significant variations in cyantraniliprole susceptibility were observed in China between 2015 and 2016 (Wang et al. 2018b). Also, in various insects, rapid reversion of insecticide resistance was observed and it is very important information for resistance management in the field (Clark et al. 1995). However, no reports characterizing cyantraniliprole-resistant B. tabaci had been published. In this study, we found that a field- Table 2 Resistance spectrum of the cyantraniliprole-selected strain and two different generations of strain of Bemisia tabaci Insecticide Strain 1) LC 50 (95% CL) (mg L −1 ) Slope±SE RF1 2) RF2 3) Cyantraniliprole MED-S 1.66 (1.40–1.92) 1.81±0.13 SX (F 2 ) 17.89 (15.10–20.87) 1.28±0.11 10.8 SX (F 15 ) 3.02 (2.55–3.50) 1.55±0.12 1.8 SX-R (F 15 ) 210.37 (182.34–241.24) 1.43±0.11 126.7 69.7 Abamectin MED-S 0.178 (1.50–0.21) 1.72±0.13 SX (F 2 ) 9.34 (8.22–10.54) 1.62±0.11 52.5 SX (F 15 ) 0.32 (0.28–0.36) 1.58±0.11 1.8 SX-R (F 15 ) 0.26 (0.22–0.30) 1.42±0.11 1.5 0.8 Imidacloprid MED-S 8.08 (6.44–9.86) 1.72±0.11 SX (F 2 ) 168.27 (146.35–191.21) 1.60±0.11 20.8 SX (F 15 ) 16.86 (14.53–19.33) 1.47±0.11 2.1 SX-R (F 15 ) 13.35 (9.30–17.58) 1.34±0.11 1.7 0.8 Thiamethoxam MED-S 19.53 (17.39–21.84) 1.82±0.12 SX (F 2 ) 305.74 (259.49–353.59) 1.39±0.11 15.7 SX (F 15 ) 17.66 (15.24–20.21) 1.46±0.11 0.9 SX-R (F 15 ) 22.64 (18.56–26.74) 1.31±0.11 1.2 1.3 Sulfoxaflor MED-S 9.78 (8.70–10.95) 1.78±0.11 SX (F 2 ) 11.59 (9.51–13.68) 1.34±0.11 1.2 SX (F 15 ) 12.42 (10.31–14.53) 1.38±0.11 1.3 SX-R (F 15 ) 14.14 (12.70–15.63) 2.17±0.13 1.4 1.1 Bifenthrin MED-S 89.60 (78.33–102.15) 1.49±0.11 SX (F 2 ) 323.44 (270.87–378.20) 1.27±0.11 3.6 SX (F 15 ) 202.56 (174.08–233.42) 1.36±0.11 2.3 SX-R (F 15 ) 182.27 (160.39–205.60) 1.64±0.11 2.0 0.9 1) MED-S, Mediterranean susceptible strain; SX, strain without selection from the Shanxi field-evolved resistant population; SX-R, cyantraniliprole-selected strain from the Shanxi field-evolved resistant population. 2) RF1 (resistance factor 1)=LC 50 (SX-R or SX) /LC 50 (MED-S) 3) RF2 (resistance factor 2)=LC 50 (SX-R)/LC 50 (SX at F 15 )