JIA-2019-11

2573 WANG Ran et al. Journal of Integrative Agriculture 2019, 18(11): 2571–2578 discs of cotton (2.0 cm diameter) were immersed for 15 s in each concentration of insecticide or in distilled water as a control. The dried discs were placed abaxial side down on a bed of agar (2 mL of 15 g L −1 ) within a plug seal cap in the tubes, and 35–55 randomly collected adults were put in each tube. All tested insects were placed at (26±1)°C and (60±10)% RH, and the mortality of each bioassay was checked after 48 h. According to previous study of synergism test in B. tabaci (Wang and Wu 2007), 100 mg L −1 of TPP, DEM, and PBO were added to each treatment to analyze their synergism with cyantraniliprole. PoloPlus (LeOra Software 2002) was utilized to analyze the data from all bioassays. 2.4. Inheritance test To clarify the inheritance of the cyantraniliprole-resistant selected strain (SX-R), reciprocal crosses were established using the susceptible strain MED-S. Reciprocal crossing was conducted using the method of Wang et al. (2009). In each experiment, approximately 200 pseudopupae were randomly selected and individually put into wells of a 96-well microplate covered with plastic sheeting. After 24 to 48 h, the unmated females emerged and were collected, and were then divided into six groups (10 females in each group). After that, 20 males were transferred into each group and each group was moved into a clip cage (3.5 cm in diameter) on the leaf of a cotton plant. Adults were allowed to mate for 5–6 days. Dominance levels were calculated according to Stone’s method (Stone 1968), which evaluates the degree of dominance ( D ) based on the LC 50 of the parental generation (in this case MED-S and SX-R) and their F 1 progeny. The D values range from –1 (completely recessive) to 1 (completely dominant). PoloPlus (LeOra Software 2002) was utilized to analyze the data from all bioassays. 3. Results 3.1. Development and stability of cyantraniliprole resistance In Table 1, resistance level of SX at the F 1 generation was 26.4-fold higher than MED-S strain. Resistance levels of cyantraniliprole in SX and SX-R were evaluated each generation from F 3 to F 16 (Table 1). In SX, resistance of cyantraniliprole reverted sharply during the first three generations (from 26.4- to 5.0-fold) and then was stable at about 4-fold throughout the subsequent 13 generations. SX-R was selected with cyantraniliprole from F 3 of SX, and its resistance level increased from 21.4-fold at F 3 to 125.7- fold at F 10 , and then was stable at around 120-fold between F 11 and F 16 . 3.2. Cross-resistance patterns Compared with MED-S, the F 2 progeny of SX displayed low to moderate levels of resistance to cyantraniliprole (10.8- fold), imidacloprid (20.8-fold), thiamethoxam (15.7-fold), and abamectin (52.5-fold), but no obvious resistance to sulfoxaflor and bifenthrin (Table 2). Reversion of resistance to abamectin (52.5- to 1.8-fold), imidacloprid (20.8- to 1.8-fold), and thiamethoxam (15.7- to 0.9-fold) occurred Table 1 Selection for cyantraniliprole resistance in strain of Bemisia tabaci collected from Shanxi Province, China 1) Generation SX strain (without selection) SX-R strain (selected with cyantraniliprole) LC 50 (95% CL) (mg L −1 ) Slope±SE RF 2) LC 50 (95% CL) (mg L −1 ) Slope±SE RF 2) 1 43.84 (37.36–51.27) 1.24±0.10 26.4 2 19.54 (14.67–25.24) 1.28±0.11 11.8 3 8.35 (7.02–9.75) 1.30±0.11 5.0 35.60 (29.18–42.58) 1.08±0.11 21.4 4 5.36 (4.06–6.66) 1.01±0.11 3.2 43.26 (36.90–50.36) 1.30±0.11 26.1 5 4.60 (3.37–5.82) 0.98±0.10 2.8 52.86 (45.09–62.05) 1.24±0.11 31.8 6 2.75 (2.14–3.36) 1.11±0.10 1.7 49.54 (42.34–57.88) 1.26±0.11 29.8 7 3.35 (2.95–3.75) 1.93±0.13 2.0 75.73 (64.96–87.41) 1.38±0.11 45.6 8 4.13 (3.44–4.87) 1.20±0.10 2.5 96.58 (86.80–107.04) 2.02±0.12 58.2 9 5.42 (3.77–7.51) 1.06±0.11 3.3 126.07 (109.95–142.80) 1.64±0.11 75.9 10 4.69 (3.35–6.25) 1.15±0.10 2.8 208.65 (186.45–232.73) 1.88±0.12 125.7 11 3.88 (3.39–4.39) 1.65±0.11 2.3 171.84 (146.54–198.56) 1.38±0.11 103.5 12 5.02 (4.08–6.07) 1.01±0.10 3.0 189.40 (163.84–216.84) 1.43±0.11 114.1 13 5.68 (4.78–6.73) 1.15±0.11 3.4 195.59 (174.47–218.24) 1.85±0.12 117.8 14 4.56 (3.29–6.01) 1.22±0.11 2.7 184.93 (159.77–211.86) 1.42±0.11 111.4 15 2.87 (2.42–3.32) 1.57±0.12 1.7 206.82 (178.41–238.09) 1.38±0.11 124.6 16 4.85 (4.12–5.65) 1.27±0.11 2.9 229.76 (185.63–283.12) 1.76±0.11 138.4 1) SX, strain without selection from the Shanxi field-evolved resistant population; SX-R, cyantraniliprole-selected strain from the Shanxi field-evolved resistant population. 2) RF (resistance factor)=LC 50 (SX or SX-R)/LC 50 (MED-S)