JIA-2019-11

2575 WANG Ran et al. Journal of Integrative Agriculture 2019, 18(11): 2571–2578 derived cyantraniliprole-resistant population was unstable in SX and that this trait could be used for suspension of using insecticide to delay the resistance (Clark et al. 1995). For example, in cases where high resistance to abamectin and chlorantraniliprole has evolved in the field, use of two agents is supposed to be suspended promptly, and can only be used again after several generations of withdrawal (Pu et al. 2010; Wang et al. 2013). Patterns of cross-resistance could provide very important theoretical significance and implications for the management of resistance when rotating insecticides to control B. tabaci . In some lepidopteran pests, cross-resistance to chlorantraniliprole in cyantraniliprole-resistant populations has been observed, most likely because the two chemical agents belong to the same class (Liu et al. 2015; Sang et al. 2016). It is well known that chlorantraniliprole, the first commercialized diamide, is not useful for controlling sucking pests. Based on some previous studies, there was minimal to almost no cross-resistance to cyantraniliprole in different pests resistant to common insecticides (Foster et al. 2012; Sang et al. 2016). In this study, SX-R, the lab-selected cyantraniliprole-resistant strain, showed no cross-resistance to such conventional insecticides as abamectin, imidacloprid, thiamethoxam, sulfoxaflor, and bifenthrin. Therefore, rotation of cyantraniliprole and the other insecticides could be applied in rotational application of insecticides to postpone development of resistance to cyantraniliprole. Reciprocal crossing between resistant and susceptible populations can be used to clarify the inheritance of resistance, which is critical for managing insecticide resistance. Considering that cyantraniliprole is a relatively novel chemical agent, there are only a few studies on resistance to cyantraniliprole. In a cyantraniliprole-resistant population of Plutella xylostella , autosomal and incompletely recessive resistance was indicated (Liu et al. 2015). In our study, the cyantraniliprole-resistant strain of B. tabaci was autosomally inherited and incompletely dominant, which is the first report about dominance levels of resistance to cyantraniliprole in B. tabaci . Incompletely dominant traits were also found in pyriproxyfen- and imidacloprid-resistant populations of B. tabaci (Horowitz 2003; Wang et al. 2009) and it has been also found that dominant resistance trait could be conducive to the development of resistance (Pu et al. 2010). Moreover, fitness cost is another important biological parameter that could be contributed to draw up better strategies of resistance management, and thus we plan to conduct further work on fitness costs associated with cyantraniliprole resistance. Cyantraniliprole is a new anthranilic diamide insecticide, and resistance to this compound has not been reported in many important pests, therefore, information about mechanisms of resistance to cyantraniliprole is limited. The present study showed that PBO inhibited cyantraniliprole Table 3 Efficacy of cyantraniliprole in susceptible and resistant strains of Bemisia tabaci and their F 1 progeny from reciprocal crosses Strain or cross 1) LC 50 (95% CL) (mg L −1 ) Slope±SE RR 2) D 3) MED-S 1.66 (1.40–1.92) 1.81±0.13 1 SX-R (F 15 ) 210.37 (182.34–241.24) 1.43±0.11 126.7 F 1A (MED-S ♂×SX-R ♀) 124.95 (108.53–143.81) 1.37±0.11 75.3 0.78 F 1B (SX-R ♂×MED-S ♀) 120.38 (104.28–138.56) 1.37±0.11 72.5 0.77 F 1 (pooled) 126.74 (109.81–146.40) 1.35±0.11 76.3 0.79 1) MED-S, Mediterranean susceptible strain; SX-R, cyantraniliprole-selected strain from the Shanxi field-evolved resistant population; F 1A , F 1 progenies from MED-S ♂×SX-R ♀; F 1B , F 1 progenies from MED-S ♀×SX-R ♂. 2) RR (resistance ratio)=LC 50 (SX-R or F 1 )/LC 50 (MED-S ) 3) The degree of dominance ( D ) ranges from −1 (completely recessive) to +1 (completely dominant). Table 4 Synergistic effects of three synergists on cyantraniliprole toxicity in susceptible and resistant strains of Bemisia tabaci Strain 1) Insecticide/Synergist 2) LC 50 (95% CL) (mg L −1 ) Slope±SE SR 3) MED-S Cyantraniliprole 1.46 (1.20–1.72) 1.73±0.13 Cyantraniliprole+PBO 1.51 (1.25–1.76) 1.82±0.14 1.0 Cyantraniliprole+DEM 1.49 (1.21–1.75) 1.70±0.13 1.0 Cyantraniliprole+TPP 1.62 (1.35–1.88) 1.75±0.13 0.9 SX-R Cyantraniliprole 225.03 (199.56–253.20) 1.68±0.11 Cyantraniliprole+PBO 49.26 (43.71–55.47) 1.66±0.11 4.6 Cyantraniliprole+DEM 236.13 (209.13–266.54) 1.62±0.11 1.0 Cyantraniliprole+TPP 212.43 (188.27–238.93) 1.65±0.11 1.1 1) MED-S, Mediterranean susceptible strain; SX-R, cyantraniliprole-selected strain from the Shanxi field-evolved resistant population. 2) PBO, piperonyl butoxide; DEM, diethyl maleate; TPP, triphenyl phosphate. 3) SR (synergistic ratio)=LC 50 Cyantraniliprole only/LC 50 (Cyantraniliprole+Synergist)