为了研究高效氯氰菊酯不同施用强度对桔小实蝇Bactrocera dorsalis(Hendel)高抗品系抗药性发展动态的影响,为指导田间科学合理使用高效氯氰菊酯防治该虫提供理论依据,本文以室内培育的桔小实蝇对高效氯氰菊酯高抗品系成虫为研究对象,以高效氯氰菊酯对敏感品系的毒力作为毒力基准线,按高效氯氰菊酯汰选间隔时间长短设置30 d、60 d、90 d、120 d 4个处理,以在不接触药剂常规条件下饲养的高抗品系作对照,采用药膜法进行抗药性汰选和毒力测定,每30天试验1次,共计试验10次,获得致死中浓度(LC_(50))和抗性倍数(R_m),分析抗性发展动态与汰选间隔时间的关系。研究结果表明270 d后,不同间隔时间长度汰选处理,桔小实蝇高抗品系对高效氯氰菊酯的抗药性发展动态存在明显差异,总体表现为汰选间隔时间越短,抗性增长越快。30 d汰选1次处理,高效氯氰菊酯对桔小实蝇成虫的致死中浓度从第1次的582.7 mg/L上升到1133.6 mg/L,抗性倍数从98.0倍上升到190.7倍;60 d汰选1次处理,致死中浓度上升为828.0 mg/L,抗性倍数上升为139.3倍;90 d汰选1次处理,致死中浓度为529.2 mg/L,抗性倍数为89.0倍;120 d汰选1次处理,致死中浓度、抗性倍数分别为511.3 mg/L、86.0倍;未进行汰选的抗性品系致死中浓度由582.7 mg/L下降到368.1 mg/L,抗性倍数也从98.0倍下降到61.9倍。建立了270 d后高效氯氰菊酯汰选间隔时间与桔小实蝇成虫抗药性增长比率之间的关系方程为Y=11.427X~(-0.529)。由实验室模拟实验结果预测当果园中连续两次使用间隔时间在99 d以上时,应可降低桔小实蝇对高效氯氰菊酯的抗性继续上升的风险。
To study on the resistance dynamic of Bactrocera dorsalis( Hendel) high-resistant strain under using beta-cypermethrin with different frequency,for purpose of providing the basis for scientific and rational usage of beta-cypermethrin to control this pest in the fields,B. dorsalis adults with high resistance to beta-cypermethrin selected under the laboratory conditions were tested, and the toxicity of betacypermethrin to the susceptible strain was toxicity baseline. Depending on the time interval length of selection with beta-cypermethrin,four treatments including 30 d,60 d,90 d and 120 d were set. The high resistance strain without contacting pesticides kept continuously under normal conditions was as control. Theresistance-selection and toxicity assay both with the pesticide film method were determined once every 30 days,and these tests reached ten times totally. The analysis of the relationship between the resistance dynamics and the selection time intervals was based on the median lethal concentration( LC_(50)) and resistant multiple( R_m). The results showed that,270 days after treatment,there were obvious differences among the resistance development for B. dorsalis strains to beta-cypermethrin at different time interval selections,and as the selected time interval was shorter,the resistance increased faster. At the treatment of once selection every 30 days,LC_(50) of B. dorsalis adults to beta-cypermethrin rose to 1133. 6 mg/L from the first time 582. 7 mg/L,and R_malso rose to 190. 7 folds from 98. 0 folds. When the selection was taken once every 60 days,LC_(50) and R_mwere 828. 0 mg/L and 139. 3 folds,respectively. LC_(50) was 529. 2 mg/L and R_m was 89. 0 folds at the treatment of once every 90 days. LC_(50) and R_mwere 511. 3 mg/L and 86. 0 folds,respectively,at the treatment of once every 120 days. LC_(50) of the resistant strain without resistance-selection decreased to 368. 1 mg/L from the first time 582. 7 mg/L,and R_malso decreased to 61. 9 folds from 98. 0 folds.