6种杀螨剂对石榴小爪螨的毒力测定

[目的]石榴小爪螨近年在陕西汉中危害园林建筑植物樟树,亟需筛选有效药剂进行防治。[方法]利用6种杀螨剂、按药膜法对其雌螨实施毒力测定,分析急性触杀效果。[结果]各供试杀螨剂致死浓度对数值与雌螨校正死亡率机率值相关显著,毒力回归式斜率为1.59~3.70,LC50值为0.3~4540.6μg a.i./L,而LC95值为1.0~48981μg a.i./L。毒力强弱次序为15%苯丁.哒螨灵乳油>15%哒螨灵乳油>2%阿维菌素乳油>30%哒螨灵可湿性粉剂>25%三唑锡可湿性粉剂。以三唑锡LC50值为标准估算,苯丁.哒螨灵相对毒力指数为12986倍,其他杀螨剂位此极值间。[结论]供试杀螨剂都能以较低剂量杀死石榴小爪螨实验种群;其LC95值的10倍浓度可用作户外防治此螨的参考剂量。

Evaluation of Toxicity of Six Acaricides on the Avocado Brown Mite

The avocado brown mite,Oligonychus punicae(Acariformes: Tetranychidae) have been injuring camphor trees,a horticultural and forest architectural plant,in Hanzhong,Shaanxi,China,in recent years,and they are needed to be controlled.[Methods] Under a procedure of residual film method,six acaricides were assayed to evaluate their acute contact toxicity on female mites.[Results] The analyses indicated that log lethal concentrations of each acaricide were correlated significantly to probits of corrected female mortalities;the slopes of the regression equations for toxicity ranged from 1.59 to 3.70;LC50 was 0.3-4 540.6 μg a.i./L,and LC95,1.0-48?981 μg a.i./L.Arranged in toxicity from strong to weak,the rank was: mixture of fenbutatin oxide·pyridaben 15% EC>pyridaben 15% EC>avermectins 2% EC>pyridaben 30% WP >azocyclotin 25% WP.Estimated on LC50 of azocyclotin,the index of relative toxicity of fenbutatin oxide·pyridaben was 12?986 folds and that of the other acaricides was between the extremes.[Conclusions] The acaricides tested are all able to cause experimental populations of O.punicae to death in much lower doses;a 10-fold concentration dose of current LC95 can be referred to apply outdoors to control the mite pest.