噻虫嗪及其代谢物噻虫胺在枸杞中的残留消解及膳食摄入风险评估

为分析50%噻虫嗪水分散粒剂在枸杞上的残留情况, 评估其残留量对人体的膳食摄入风险, 建立了噻虫嗪及其代谢物噻虫胺在枸杞上的高效液相色谱-串联质谱检测方法, 分析枸杞中农药的最终残留量, 估算农药慢性摄入风险。结果表明, 在0.01~1.0 mg/L的范围内, 2种农药的线性关系良好, 相关系数大于0.999。在0.01、0.1、1.0 mg/kg 3个添加水平下, 平均回收率为80.7%~106.6%, 相对标准偏差为1.4%~4.6%。储藏稳定性试验结果表明, 冷冻条件下储藏11个月, 噻虫嗪和噻虫胺在枸杞中均稳定。中国居民摄入噻虫嗪和噻虫胺的慢性暴露风险分别为16.6%和3.8%, 远低于100%, 慢性膳食暴露风险低。     

不同施药方式下噻虫嗪和噻虫胺对韭菜迟眼蕈蚊的防治效果

为提高田间韭菜养根期噻虫嗪和噻虫胺对韭菜迟眼蕈蚊的防治效果,通过喷淋和灌溉施药方式研究了噻虫嗪和噻虫胺在土壤中的分布情况、喷淋施药后在田间的移动性以及对韭蛆的防治效果和对韭菜生长指标的影响。结果表明,喷淋施药比灌溉施药利于药液到达地下靶标位置,且药剂浓度随着土壤深度增加而减小;喷淋施药后药剂在韭菜根部土壤中的浓度明显高于其在行间土壤中的浓度;施药后120 d与7 d相比,药剂在垂直方向上出现下移,在水平方向上随水流方向移动;12 kg(a.i.)/hm2噻虫嗪和3、6 kg(a.i.)/hm2噻虫胺喷淋施药后对韭菜迟眼蕈蚊的防治效果在80%以上,且均可维持120 d以上,并对韭菜生长有促进作用。因此,利用噻虫嗪和噻虫胺喷淋施药防治韭菜养根期的韭菜迟眼蕈蚊是可行的。     

The impact of restrictions on neonicotinoid and fipronil insecticides on pest management in maize,oilseed rape and sunflower in eight European Union regions

BACKGROUND

In 2013, the European Commission restricted the use of three neonicotinoids (clothianidin, imidacloprid and thiamethoxam) and the pyrazole fipronil, which are widely used to control early‐season pests. Here, we used original farm survey data to examine the impact of the restrictions on pest management practices in eight regional case studies including maize, oilseed rape and sunflower in seven European Union (EU) countries.

RESULTS

In four case studies, farmers switched to using untreated seeds as no alternative seed treatments were available. In three case studies, farmers switched to using unrestricted neonicotinoid‐ or pyrethroid‐treated seeds. In five case studies, farmers increased the use of soil or foliar treatments, with pyrethroids as the principal insecticide class. Other changes in pest management practices ranged from increased sowing density to more frequent scouting for pests. Many farmers perceived that the time, cost and amount of insecticides required to protect crops increased, along with pest pressure. Alternative seed treatments were mostly perceived as being less effective than the restricted seed treatments.

CONCLUSION

Farmers generally relied on alternative seed treatments or more soil/foliar treatments in the first growing season after the restrictions took effect. Further study is required to assess the effectiveness and sustainability of these alternatives compared with the restricted insecticides. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

噻虫嗪及其代谢物噻虫胺在节瓜中的消解动态及初步膳食风险评估

为明确噻虫嗪在节瓜上的残留行为,于2015年在广东和上海两地进行了噻虫嗪在节瓜上的规范田间残留试验,建立了节瓜中噻虫嗪及其代谢物噻虫胺残留量的高效液相色谱-串联质谱 (HPLC-MS/MS) 检测方法。样品用乙腈提取,经氨基固相萃取小柱净化,HPLC-MS/MS 检测,外标法定量。结果表明:噻虫嗪在节瓜上的消解半衰期为4.98~5.84 d;采用25%噻虫嗪水分散粒剂 (WG),分别按有效成分75和112.5 g/hm2 的剂量于幼果期开始施药,施药2~3次,每次施药间隔期为7~10 d,距最后一次施药后3、5、7 d 采样测定,节瓜中噻虫嗪和噻虫胺的残留量分别为0.010~0.422 mg/kg和 <0.010~0.020 mg/kg。膳食摄入风险初步评估结果显示:其风险商值 (RQ) 为0.044,表明噻虫嗪的长期膳食摄入风险较低。目前中国尚未制定噻虫嗪在节瓜上的最大允许残留限量 (MRL) 标准,根据试验结果,建议中国可将噻虫嗪在节瓜上的MRL值暂定为1 mg/kg。     

噻虫嗪及其复配制剂不同施药方法对3种甘蔗害虫的防控效果

选择噻虫嗪及其复配制剂,采用不同施药方法对稻蛀茎夜蛾、甘蔗粉角蚜和甘蔗蓟马进行防治。结果表明,结合甘蔗下种,30%氯虫·噻虫嗪悬浮剂600~750mL/hm2、40%氯虫·噻虫嗪水分散粒剂600~750g/hm2与底肥一起施用,对苗期稻蛀茎夜蛾防效为70%～75%; 结合甘蔗大培土,25%噻虫嗪水分散粒剂600g/hm2、70%噻虫嗪种子处理可分散粉剂225~300g/hm2、30%氯虫·噻虫嗪悬浮剂600~750mL/hm2、40%氯虫·噻虫嗪水分散粒剂600g/hm2与追肥一起施用,药后45d对甘蔗粉角蚜防效达98%以上,对甘蔗蓟马防效达70%以上; 在甘蔗伸长期,25%噻虫嗪水分散粒剂600g//hm2、70%噻虫嗪种子处理可分散粉剂225~300g//hm2、30%氯虫·噻虫嗪悬浮剂600~750mL/hm2对水450kg/hm2淋浇甘蔗根区,药后15 d对甘蔗粉角蚜防效为90%以上。农药根施防治甘蔗害虫,方法简单易行,持效期长,且对环境友好,是一种简便高效的害虫防治施药技术。     

Note: Effect of the surfactant BB5 on the potency of thiamethoxam against the whiteflyBemisia tabaci

BB5, an alkyl phenoxy polyethylene ethanol formulated in acidic buffer, is an adjuvant added usually to various pesticides to potentiate their activities on various biological systems. Addition of 0.2% BB5 resulted in a considerable increase of thiamethoxam toxicity onBemisia tabaci (Gennadius) nymphs. According to LC₅₀ values, the combined effect was over 25-fold higher than that of thiamethoxam alone. On the other hand, no appreciable combined effect was observed when BB5 and thiamethoxam were applied together onB. tabaci adults. The importance of these results is discussed. http://www.phytoparasitica.org posting Dec. 20, 2004.     

噻虫胺种子处理对西瓜生长发育的影响及其残留分析

为明确新烟碱类杀虫剂噻虫胺种子处理对西瓜生长发育和品质的影响, 以及在西瓜中的残留状况, 本研究以10%噻虫胺种子处理悬浮剂为供试药剂, 采用拌种试验, 开展噻虫胺对西瓜生长发育的影响及残留分析研究。结果表明, 噻虫胺有效成分用量100~250 g/100 kg范围内, 对西瓜出苗安全; 噻虫胺拌种处理对西瓜苗期的株高、茎粗、叶绿素含量和叶面积有一定的促进作用, 随着西瓜的生长促进作用减弱, 西瓜出苗后30 d, 各处理间差异不显著; 噻虫胺各处理西瓜产量均高于空白对照, 对西瓜有一定的增产作用; 噻虫胺拌种可不同程度地提高西瓜果实中可溶性糖、可溶性固形物含量, 提升西瓜的品质; 随着西瓜生长发育, 叶片内噻虫胺含量逐渐降低, 出苗后45 d, 叶片内未检测到噻虫胺残留; 西瓜收获时果实中未检测到噻虫胺残留, 西瓜根部土壤中噻虫胺的残留量在0.041 2~0.097 5 mg/kg之间。综上所述, 噻虫胺100~250 g/100 kg用量范围内处理西瓜种子, 对西瓜苗期生长有一定促进作用, 并可提高产量, 改善西瓜的品质, 叶片内噻虫胺含量随植株生长逐渐降低, 果实中无残留, 本研究为噻虫胺种子处理在西瓜生产实践中合理、安全、高效的应用提供技术支撑。     

Inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase lower fecundity in the German cockroach: correlation between the effects on fecundity in vivo with the inhibition of enzymatic activity in embryo cells

The enzyme 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase is crucial to insect development and reproduction, as revealed by the sterilising properties of some specific inhibitors of it. In the present paper, we study the sterilising effects of a number of HMG-CoA reductase inhibitors on the German cockroach, Blattella germanica (L). The inhibitors tested were naringenin, lovastatin, mevastatin, simvastatin, atorvastatin and fluvastatin. The first two compounds were ineffective or scarcely effective as HMG-CoA reductase inhibitors. The most active compounds in vivo were fluvastatin and atorvastatin, followed by simvastatin and mevastatin. They were equally ranked when tested as HMG-CoA reductase inhibitors in the B germanica embryonic derived cell line UM-BGE-1. This suggests that this cell line may be an appropriate tool for testing HMG-CoA reductase inhibitors and so to predict their properties as insect sterilising agents with insecticide potential.     

50%噻虫嗪悬浮种衣剂的研制及其对棉花蚜虫的防治效果

为研制高含量的噻虫嗪悬浮种衣剂,提高其对棉花蚜虫的防治效果,分别采用流点法及因素轮选法等对润湿剂、分散剂、成膜剂和增稠剂等助剂进行筛选及优化,最终采用湿法砂磨超微粉碎法研制了50%噻虫嗪悬浮种衣剂,对其性能指标进行了测试,并测定了其对棉花种子发芽势和发芽率的影响以及对棉花蚜虫的田间防治效果。结果表明:以质量分数为50%的噻虫嗪为有效成分、3%的FD及1%的BC-10为润湿剂、2.5%的SP-2836及2.5%的SK-24为分散剂、1%的硅酸铝镁及0.05%的黄原胶为增稠剂和2.5%的BF308为成膜剂而研制的50%噻虫嗪悬浮种衣剂性状良好,悬浮率高,热贮稳定性好,对棉花种子的发芽势及发芽率的影响较清水对照差异显著。田间试验结果显示,在有效剂量为187.5 g/hm2时50%噻虫嗪悬浮种衣剂对棉花4、5叶期蚜虫的防效分别达83.94%和53.94%,适合田间应用。     

Insecticidal activity and nicotinic acetylcholine receptor binding of dinotefuran and its analogues in the housefly, Musca domestica

The insecticidal activity of dinotefuran and 23 related compounds against the housefly, Musca domestica (L) was measured by injection with metabolic inhibitors. Dinotefuran was less active than imidacloprid and clothianidin by a factor of 10 in molar concentrations. Their binding activities to the fly-head membrane preparation were measured by using [125I]alpha-bungarotoxin ([125I]alpha-BGTX) and [3H]imidacloprid ([3H]IMI) as radioligands. The activity of some selected compounds measured with [3H]IMI was 10(4)-fold higher than that measured with [125I]alpha-BGTX. With [3H]IMI as a radioligand, dinotefuran was 13-fold less active than imidacloprid. The inhibitory effect of dinotefuran on the binding of [3H]IMI to the membrane preparation was in a competitive manner. Quantitative analysis of the insecticidal activity of the test compounds with the binding activity measured with [3H]IMI showed that the higher the binding activity, the higher was the insecticidal activity.     

Effect of substituents at the 5-position of the pyridine ring of imidacloprid on insecticidal activity against Periplaneta americana

The insecticidal activities of imidacloprid derivatives with a wide range of substituents at the 5-position on the pyridine ring against American cockroaches, Periplaneta americana (L.), were measured by injection with and without synergists propyl 2-propynyl phenylphosphonate and piperonyl butoxide. The log(1/MLD) value (MLD = minimal lethal dose in mol) without synergists was 7.96 for the methyl derivative, and the values were lower for other derivatives. Synergists enhanced the potencies of all the compounds tested. Considering these compounds and those with other substituents at this position, the region for maximum activity was predicted to be in the conjunction of the pyridyl 6-chlorine atom with a lipophilic small group in the 5-position.     

70%噻虫嗪种子处理可分散粉剂和10%吡虫啉可湿性粉剂拌种对马铃薯甲虫的防效

利用药剂拌种处理马铃薯种薯后播种的方法,研究比较了2种新烟碱类杀虫剂对马铃薯甲虫的活性和防治效果。结果表明,按药剂有效成分18 g/100 kg种薯拌种,70%噻虫嗪种子处理可分散粉剂拌种出苗后60 d对马铃薯甲虫幼虫的生物活性和防效较高,卵块孵化率较低,死亡率在61.1%以上,防效达57.3%,孵化率为36%,这有利于降低马铃薯甲虫种群数量,减轻为害。而10%吡虫啉可湿性粉剂拌种出苗后60d对马铃薯甲虫幼虫生物活性和防效较低,卵块孵化率较高,死亡率在12.5%以下,防效为37.1%,孵化率为64.6%,对马铃薯甲虫的控制效果较差。     

氯虫•噻虫嗪不同剂型对水稻二化螟、稻纵卷叶螟的防治效果及施用技术

2007-2008年,应用氯虫&#8226;噻虫嗪不同剂型防治水稻二化螟、稻纵卷叶螟的田间试验结果表明：0.6%氯虫&#8226;噻虫嗪颗粒剂对二化螟的效果较好,但难以控制稻纵卷叶螟危害;40%氯虫&#8226;噻虫嗪水分散粒剂可有效防控以上2种虫害且持效期长达30 d。同一时期同等剂量下,各施用1次0.6%氯虫&#8226;噻虫嗪颗粒剂、40%氯虫&#8226;噻虫嗪水分散粒剂,前者撒施处理对其药效均显著低于后者茎叶喷雾处理。     

Phytotoxic activity of clomeprop in soil and concentration of its hydrolysed metabolite DMPA in soil water

The relationship between the fate of clomeprop in soil and its phytotoxic activity on the growth of radish (Raphanus sativus) seedlings was investigated in the laboratory. The phytotoxic activity of clomeprop in sea sand was much higher than in non-autoclaved soil, and the phytotoxic activity in non-autoclaved soil was higher than in autoclaved soil. The phytotoxic activity of 2-(2,4-dichloro-3-methylphenoxy)propionic acid (DMPA), a hydrolysed metabolite of clomeprop, was higher than that of the latter under both soil conditions. Clomeprop was adsorbed on soil to a greater extent than DMPA. The concentration of clomeprop in soil water of non-autoclaved soil decreased with increase of the DMPA concentration in the soil water in a time-dependent manner. It is suggested that the phytotoxic activity of clomeprop applied to soil is induced mostly by the DMPA concentration in soil water after hydrolytic degradation by soil microbes. © 1999 Society of Chemical Industry     

Correlations of the electrophysiological activity of neonicotinoids with their binding and insecticidal activities

The electrophysiological actions of various neonicotinoids, including substituted benzyl derivatives, against recombinant Drosophila SAD/chicken beta2 hybrid nicotinic acetylcholine receptor (nAChR) were measured to analyze the relationships between the in vivo (insecticidal) and in vitro (binding and agonist) activities. Most of the neonicotinoids tested were capable of inducing inward currents by activating the hybrid nAChRs expressed in Xenopus laevis oocytes, whereas some compounds had no agonist activity and only blocked the acetylcholine-induced currents. Variations in the agonist activity were well correlated with those in the binding potency evaluated using [3H]imidacloprid as well as insecticidal activities.