Abstract: 【Objective】The objective of this study is to evaluate the toxicity and persistence of the spirotetramat, a new two-way systemic insecticide, to the peach aphid (Myzus persicae).【Method】Three bioassay methods were tested in the laboratory. The toxicity was analyzed using probit analysis and time-dose-mortality. Additionally, the persistence of this pesticide was studied using clip-cage method.【Result】The bioassay results differed among the three bioassay methods, i.e. clip-cage, triplex-glass and round-leaf methods. The clip-cage method kept the leaf the longest time and generated more reliable result. The mortality of the aphid nymph increased with the increasing of detecting time, reached the highest value at 120 h after spray. The probit analysis showed that the LC50 of triplex-glass, clip-cage and round-leaf method was 0.0886, 0.1258 and 0.8459 mg•kg-1, respectively. The time-dose-mortality analysis showed that, at 1.5625 mg•kg-1, LT50 of triplex-glass, clip-cage and round-leaf method was 2.5, 2.9 and 3.5 d, respectively. The LT50 decreased with the increasing of the concentration of the spirotetramat. The spirtetramat had a long time of persistence. The mortality of the aphid nymph decreased from 100% to less than 20% after spray for seven days.【Conclusion】The study suggests that the clip-cage for the bioassay of the spirotetramat will contribute to the bioassay method of those pesticides with long time of persistence. The peach aphids collected from the field of Beijing area of China are sensitive to the spirotetramat.

Key words: spirotetramat , Myzus persicae , bioassay , clip-cage method , persistence