三种杀螨剂对山楂叶螨的毒力评价

为筛选出高效防治山楂叶螨Amphitetranychus viennensis Zacher的杀螨剂,利用玻片浸渍法和叶片残毒法测定了3种杀螨剂对其3种螨态的室内毒力,并对不同浓度杀螨剂的田间防效进行了测定。结果表明:240 g/L螺螨酯、110 g/L乙螨唑和43%联苯肼酯中仅联苯肼酯对山楂叶螨雌成螨有毒力,其LC50为37.65 mg/L;3种杀螨剂均能毒杀卵及幼螨,毒力大小依次为乙螨唑联苯肼酯螺螨酯;同一杀螨剂对幼螨的毒力均高于对卵的毒力。240 g/L螺螨酯和110 g/L乙螨唑对山楂叶螨的总体防效较好,除螺螨酯4 000倍液处理的防效在药后30 d达到最大97.11%外,其余各处理均在药后15 d达到最大,防效为88.76%~96.14%;但二者速效性较差,药后1~7 d防效均低于对照;而螺螨酯4 000、5 000倍液处理及乙螨唑5 000倍液处理的持效性较好,药后30 d防效仍有97.11%、90.90%和93.06%,均显著高于对照。43%联苯肼酯对山楂叶螨的总体防效在3种杀螨剂中最高,其1 800、2 500倍液处理分别在药后7 d和3 d时防效达到最大99.79%和98.64%;1~7 d防效为97.45%~99.79%,显著高于其余杀螨剂和对照;30 d时防效分别达98.14%和96.19%,速效性和持效性均较好。表明螺螨酯和乙螨唑对山楂叶螨的持效性较好,联苯肼酯则有良好的速效性和持效性,可以按照其不同特点推广应用。     

螺螨酯和螺虫乙酯在覆膜金橘中的降解残留规律研究

为评价螺螨酯和螺虫乙酯在覆膜金橘中使用的安全性,研究了螺螨酯、螺虫乙酯及其代谢产物在覆膜金橘中的残留分析方法和残留动态规律,建立了金橘中螺螨酯、螺虫乙酯及其代谢产物的超高压液相色谱-串联质谱（UHPLC-MS/MS）检测方法。结果表明,在0.002~2.5 mg/kg添加水平范围内,螺螨酯、螺虫乙酯及其4种代谢产物在金橘中的添加回收率为86.9%~101.2%,相对标准偏差为2.3%~6.8%,方法检出限为0.1~5.0 μg/kg,定量限为0.5~ 1.0 μg/kg。螺螨酯和螺虫乙酯母体在覆膜金橘中的消解符合一级动力学方程,消解半衰期分别为14.1 d和23.1 d。最终残留实验结果表明,按照推荐的施药剂量使用,施药2次后15 d收获,螺螨酯和螺虫乙酯在覆膜金橘中的残留量均低于最大残留限量值（均为0.5 mg/kg）。     

气相色谱法同时测定土壤中4种农药的残留量

为了全面评价土壤质量安全,及时、准确地测量土壤中残留农药的种类和含量水平,采用添加回收率试验,借助气相色谱–电子捕获检测器(GC–ECD),建立了同时分析和检测己唑醇、稻瘟酰胺、螺螨酯和苯醚甲环唑在土壤中残留量的方法。结果表明:土壤样品用乙腈经超声波提取15 min,再用弗罗里硅土柱净化后(用50 m L乙腈分次淋洗),在优化后的气相色谱条件(初始温度180℃,保持3 min,以20℃/min升至260℃,保持7 min,进样口温度280℃,检测器温度300℃,载气(N2)流速为5 m L/min,尾吹流速30 m L/min,进样量1μL,分流比20∶1)下对土壤样品进行分析检测,当4种农药的质量浓度为0.02~1.00 mg/L时,4种供试农药的浓度与相应色谱峰峰面积呈良好的线性关系(相关系数≥0.996 7,均达极显著水平),在0.05、0.50、1.00 mg/kg3个添加水平下的平均回收率为89.9%~100.2%,相对标准偏差为2.7%~8.6%,最小检出量均为0.05 ng,方法的定量限均为0.05 mg/kg。     

二斑叶螨对螺螨酯抗药性及对18种杀螨剂交互抗性

采自甘肃兰州兴隆山公园的二斑叶螨(Tetranychus urticae Koch),用雌雄单系培养敏感品系(S),用螺螨酯处理二斑叶螨种群培养抗性品系(SP R),用室内生测法对二斑叶螨S和SP R品系进行室内毒力测定。结果表明,二斑叶螨对螺螨酯抗性发展初期较慢,中期稳定,后期较快,选育至26代抗性指数(RI)达58.83。SP R对甲氰菊酯、氯氰菊酯有一定的交互抗性,RI分别为11.54和10.03;对苯丁锡、四螨嗪、苦皮藤生物碱、阿维菌素、氯氟氰菊酯、哒螨&#8226;四螨嗪、哒&#8226;水胺硫磷、三唑锡、三氯杀螨醇、哒螨灵、氧化乐果无交互抗性(1＜RI<5.00);对浏阳霉素、毒死蜱、噻螨酮、柴油、哒螨灵、唑螨酯可能存在负交互抗性(RI<1)。     

Spirodiclofen and spirotetramat bioassays for monitoring resistance in citrus red mite, Panonychus citri (Acari: Tetranychidae)

BACKGROUND: Citrus red mite, Panonychus citri (McGregor), is a key pest of San Joaquin Valley California citrus. Spirodiclofen was registered for mite control in 2007, and spirotetramat for scale control in 2008. Because of the potential for resistance to spirodiclofen to develop in spider mites, and cross‐resistance to spirotetramat used for other citrus pests, bioassay methods for resistance monitoring were developed. RESULTS: The responses of four populations of adult female, egg and larval stages of P. citri to spirodiclofen were compared to determine the most robust bioassay method for this pesticide. Adult females responded with a higher LC₉₉ and larval stages exhibited higher control mortality and a lower slope of response compared with the egg stage. Thus, the egg stage was found to be the most suitable stage for testing. Egg production and egg shape were significantly affected by spirodiclofen treatment of adult female mites. Bioassays with the related compound spirotetramat revealed that P. citri egg hatch was less affected by this compound, requiring the assessment of mortality to be extended to 11 days after treatment when the hatched larvae succumbed to the pesticide. Discriminating concentrations of 10 ppm for spirodiclofen and 31.6 ppm for spirotetramat in an 11 day bioassay were tested against eight field populations of P. citri, and 99–100% mortality resulted. CONCLUSION: These results provide a baseline for the response of P. citri to spirodiclofen and spirotetramat that will aid resistance management in California citrus. Copyright © 2011 Society of Chemical Industry     

领美、丝迈等助剂桶混对柑橘红蜘蛛、柑橘木虱的减量增效评价

为了响应全国化肥、农药零增长和减量化,改善农业土壤生态环境、推进农业绿色发展,笔者用螺螨酯、噻虫嗪常量、减量分别添加助剂“领美、丝迈、绿颖、怀农特”桶混防控柑橘红蜘蛛、柑橘木虱,添加助剂“领美、丝迈、绿颖、怀农特”后,螺螨酯速效性增强,药后1d单剂常量防效为57.75%,加助剂增效常量、减量防效为69.3%～95.41%,防效可提高11%～37%,药后3d单剂常量防效为72.75%,加助剂增效常量、减量防效为96.79%～99.54%。添加助剂“领美、丝迈、绿颖、怀农特”后,噻虫嗪药后3d常量单剂防效为94.47%,加助剂增效常量、减量防效为97.91%～99.31%。减量增效作用明显。     

Genetic and biochemical analysis of a laboratory‐selected spirodiclofen‐resistant strain of Tetranychus urticae Koch (Acari: Tetranychidae)

BACKGROUND: Spirodiclofen is a selective, non‐systemic acaricide from the new chemical class of tetronic acid derivatives. In order to develop strategies to minimise resistance in the field, a laboratory‐selected spirodiclofen‐resistant strain of the two‐spotted spider mite, Tetranychus urticae Koch, was used to determine genetic, toxicological, biochemical and cross‐resistance data. RESULTS: Selecting for spirodiclofen resistance in the laboratory yielded a strain (SR‐VP) with a resistance ratio of 274, determined on the larval stage. The egg stage remained far more susceptible. No cross‐resistance was found against other established acaricides, except for spiromesifen. Based on synergist experiments and enzyme assays, it appeared that especially P450 monooxygenases, but also esterases and glutathione‐S‐transferases, could be involved in the metabolic detoxification of spirodiclofen. Genetic analysis showed that the resistance is inherited as an intermediate trait under control of more than one gene. CONCLUSIONS: Resistance to spirodiclofen exceeded by far the recommended field rate. A good acaricide resistance management programme is necessary to prevent fast resistance build‐up in the field. Spirodiclofen can be used in alternation with most established acaricides, except for other tetronic acid derivatives. Without selection pressure, resistance tends to be unstable and can decrease in the presence of susceptible individuals owing to the intermediate, polygenic inheritance mode. Copyright © 2009 Society of Chemical Industry