An Unexpected Hydrolysis Product from Strobilurin Fungicide: Azoxystrobin

The hydrolysis reaction of azoxystrobin in a methanol solution was studied, obtaining a novel compound 3,3-dimethoxy-2-（2-（6-methoxy pyrimidin-4-yloxy）phenyl） propanoic acid. The hydrolysis reaction may be helpful to explaining the degradation mechanism of azoxystrobin in soil or plant, which is also a method for further study on metabolism in vitro. The crystal structure was confirmed by 1H NMR and MS and determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 8.5662（2）, b = 10.5074（6）, c = 10.9849（7）, α = 62.8370（10）, β = 73.2170（10）, γ = 73.3100（2）o, C16H18N2O6, Mr = 334.32, V = 828.09（9）3, Z = 2, Dc = 1.341 g/cm3, F（000） = 352, μ = 0.104 mm-1, S = 1.075, the final R = 0.0665 and wR = 0.1593 for 2083 observed reflections with I 2σ（I） and 220 variable parameters. The crystal analysis shows that the hydrolysis product contains two rings, and a one- dimensional chain structure is formed via the intermolecular hydrogen bond O（1）–H（101）···N（2）.

Validation of a SPME-GC Method for Azoxystrobin and Pyraclostrobin in Blueberries, and Their Degradation Kinetics

Analytical method for the residues of strobilurins azoxystrobin and pyraclostrobin in blueberries was developed. Fungicide residues were determined by solid-phase microextraction (SPME) cou-pled to gas chromatography with micro-electron capture detector. The effect of pH values and fiber coatings were studied. The SPME fiber coating selected was 100 μm PDMS. The method is selective with adequate precision and high accuracy and sensitivity. Recoveries ranged within the 100% - 106% range for azoxystrobin, and 96% - 106% range for pyraclostrobin;and detection and quantification limits were 2.0 and 6.0 μg/kg for azoxystrobin, and 26.0 and 86.0 μg/kg for py-raclostrobin, respectively. Statistical parameters indicated the occurrence of matrix effect;con-sequently calibration was performed on spiked samples. Degradation of azoxystrobin and pyra-clostrobin was studied in blueberry fields located in Concordia, Argentina, with fruits from Emerald and Jewel varieties. The degradation of these fungicides in both blueberry varieties studied followed a first order rate kinetics, and the half-life for azoxystrobin was 11.6 and 17.8 days for Emerald and Jewel cultivars;and for pyraclostrobin was 5.5 and 8.0 days, respectively.

Effect of Azoxystrobin on Oxygen Consumption and cyt b Gene Expression of Colletotrichum capsici from Chilli Fruits

Azoxystrobin acts as an inhibitor of electron transport by binding to the Qo center of cytochrome b （cyt b）. Resistance to azoxystrobin was usually caused by the point mutation of cyt b gene or by the induction of alternative respiration. Oxygen consumption test for mycelia of Colletotrichum capsici showed that azoxystrobin inhibited mycelial respiration within 12 h; however, as time went on, the respiration of the mycelia recovered when the mycelia were treated with azoxystrobin and salicylhydroxamic acid （SHAM, a known inhibitor of alternative respiration）, and the oxygen consumption of the mycelia could not be inhibited. Meanwhile, cytochrome b （cyt b） gene expression increased with the recovery of mycelial respiration. The increased cyt b gene expression might play a role in the development of resistance to azoxystrobin in C. capsici.

7%吡虫啉·咯菌腈·嘧菌酯种子处理悬浮剂配方研制

开发7%吡虫啉·咯菌腈·嘧菌酯种子处理悬浮剂的配方。采用湿法研磨工艺筛选适宜的润湿分散剂、增稠剂、防冻剂、pH调节剂、成膜剂等助剂种类及其用量,确定了7%吡虫啉·咯菌腈·嘧菌酯种子处理悬浮剂优选配方:吡虫啉6%(折百)、咯菌腈0.2%(折百)、嘧菌酯0.8%(折百),润湿分散剂烷基醇聚氧乙烯醚W-6001%、乙氧基多聚芳基酚醚磷酸酯铵盐SC 2%、多聚芳基醚硫酸酯FD 3%,防冻剂乙二醇5%,pH调节剂柠檬酸0.2%,成膜剂KMM-013%,警戒色R2002SS 15%,消泡剂6300.5%,防腐剂卡松0.2%,增稠剂黄原胶0.2%、硅酸镁铝2%,珠光粉1618%,抗划痕蜡乳液SC-095%,去离子水补足至100%。该制剂配方悬浮性优,储存稳定性好,各项技术指标均符合种子处理悬浮剂的标准要求。

Dissipation pattern of azoxystrobin and difenoconazole in red dragon fruit(Hylocereus polyrhizus)cultivated in Indonesian highland(West Java)and coastal area(D.I.Jogyakarta)and its implication for dietary risk assessment

Background:Cultivation of red dragon fruit(Hylocereus polyrhizus)in Indonesian orchards is hampered by anthracnose and stem canker.A mixture of azoxystrobin 200 g/L+difenoconazole 125 g/L is recommended in supporting the obligated integrated pest management.For the consumer safety,dietary intake of the residues from fresh edible part should be assessed;therefore,information on correct dissipation pattern of the applied pesticide is required.Materials and Methods:Field residue trials in Indonesian highland(West Java)and coastal area(Special Region of Yogyakarta)were done at recommended dose was 0.151 kg ai/ha azoxystrobin and 0.094 kg ai/ha difenoconazole,three times at 10 days interval.Whole fruit samples were collected at 70%-100%ripeness at−1,0,1,3,7,10,and 14 days after last application,processed and determined its residue as soon as possible.Result and Discussion:Photoisomerization of azoxystrobin was observed at Day 0,especially in coastal area;however,it has been dissipated to below lowest validated level in the following day.At Day 0,3%-5%of the deposited azoxystrobin and difenoconazole penetrate into the flesh;however,most residues(95%-97%)were retained in peel,and dissipated in prolonged day.The dissipation pattern was non-linear.The dissipation data were better fit with bi-exponential double-first-order in parallel than single first-order kinetics model.The DT50 of both azoxystrobin and difenoconazole was 3 days.At harvest time,seventh day,only azoxystrobin residue was detected in flesh at 0.006 mg/kg;therefore,the long-term dietary risk was 0 per cent acceptable daily intake.Conclusion:Fresh red dragon fruit is safe to consume.

苯甲·嘧菌酯与水溶肥料混合使用全程防治杨梅白腐病为主的综合病害效果示范

[目的]筛选出更好的药剂组合供杨梅生产选择使用。[方法]选择32.5%苯甲·嘧菌酯SC与11%含氨基酸水溶肥料混合使用进行以杨梅白腐病为主的综合病害全程防治效果示范。[结果]该组合对杨梅白腐病为主的综合病害有较好的预防与控制作用,在杨梅谢花后、幼果-硬核期和转色期连续用药3次后,对杨梅白腐病的防效达90.61%,极显著优于农户自防区,同时对杨梅褐斑病、炭疽病等其他病害的综合效果也比较理想,且安全性好。[结论]该研究结果为进一步提高杨梅产量和品质、保证食用安全、促进杨梅产业健康可持续发展奠定了科学基础。

24.6%噻虫嗪·叶菌唑·嘧菌酯种子处理悬浮剂制备及其安全性研究

种子处理悬浮剂可从源头上防治病虫害,降低防治成本,减少环境污染。为获得有效防治小麦和水稻主要病虫害的种子处理悬浮剂,通过筛选润湿分散剂、成膜剂和增稠剂等助剂,确定24.6%噻虫嗪·叶菌唑·嘧菌酯种子处理悬浮剂(FS)优化配方,测试其安全性和生物活性。结果表明,24.6%噻虫嗪·叶菌唑·嘧菌酯FS优化配方为18.2%噻虫嗪、3.2%叶菌唑、3.2%嘧菌酯、2%聚羧酸盐类分散剂GEROPON DA13491、2%聚芳醚硫酸酯铵类分散剂FD530、0.3%黄原胶、0.5%硅酸镁铝、4%丙烯酸乳液n8、8%的8#红、0.2%苯甲酸、4%乙二醇、0.5%有机硅消泡剂BG08、去离子水补足至100%。该种子处理悬浮剂粒径(D_(90))为1.72μm,成膜性良好,脱落率小于5%,各项质量指标均符合种子处理悬浮剂企业标准。在发芽试验中,包衣后小麦和水稻种子发芽率分别达到95.67%和88.67%;在盆栽试验中,包衣后小麦和水稻种子出苗率分别为85.33%和91.33%,表明制备的种子处理悬浮剂对小麦和水稻种子安全。在此剂量下,药剂苗后30、90 d对小麦蚜虫相对防治效果分别达到32.82%、93.51%,对小麦纹枯病相对防治效果达到70.50%、34.63%;在苗后30、60 d对水稻飞虱相对防治效果达到21.44%、26.78%,对水稻稻瘟病相对防治效果达到54.99%、67.06%,表明制备的种子处理悬浮剂可防治上述小麦和水稻病虫害。

嘧菌酯与甲基硫菌灵在荔枝采后贮藏保鲜中的应用及膳食暴露评估

本文探究了常温条件下不同浓度的嘧菌酯和甲基硫菌灵对采后荔枝果实保鲜效果的影响,在贮藏期间通过对荔枝生理指标进行分析从而筛选出较优的杀菌剂配方,并对筛选后的杀菌剂配方进行验证以及膳食暴露评估,最终获得可以在常温贮藏条件下延长荔枝货架期的保鲜方法。结果发现,在25℃贮藏条件下,采用25%嘧菌酯1600倍稀释液(M1600)、25%嘧菌酯1600倍稀释液复配70%甲基硫菌灵700倍稀释液(M1600+J700)处理荔枝可以显著抑制果实的呼吸强度(P<0.05),降低果皮的相对电导率(P<0.05)和果实的腐烂率(P<0.05),且在一定程度上抑制了果肉中可溶性固形物TSS和维生素C含量的降低,较好地维持了荔枝果实的感官品质和食用价值。经对比发现,两种杀菌剂对荔枝的保鲜效果相当,但单独使用M1600在抑制荔枝果皮褐变方面效果较优。通过对贮藏期间荔枝全果和果肉中杀菌剂残留量的检测以及膳食暴露评估发现,单独使用嘧菌酯处理荔枝后整果中嘧菌酯的风险熵RQ远小于1,可以同时达到满足提高荔枝贮藏品质、安全食用以及降低经济成本的目的。该研究为荔枝等非呼吸跃变型果实采后品质提升的研究提供了技术参考。

325 g/L苯甲·嘧菌酯悬浮剂对油茶炭疽病的防效研究

油茶炭疽病(Colletotrichum camelliae)是油茶的主要病害,为害油茶叶片、果实,可导致其籽油的质量和产量严重下降,但目前尚无防治油茶炭疽病的登记药剂。采用共毒系数法进行苯醚甲环唑和嘧菌酯的混配配方筛选,混配比为5:8时,对油茶炭疽病原菌的抑菌效果EC_(50)为1.533 8 mg/L,共毒系数为128.43,表现为增效作用,为防治油茶炭疽病的最适配比。据此,选择325 g/L苯甲·嘧菌酯悬浮剂在浙江、江西和湖南3地开展田间药效试验,试验药剂在406.25 mg/kg剂量下的防效为72.51%~89.36%,显著高于2个单剂对照药剂40%苯醚甲环唑悬浮剂在133.33 mg/kg和25%嘧菌酯悬浮剂在250.00 mg/kg剂量下的防效。据此,建议325 g/L苯甲·嘧菌酯悬浮剂防治油茶炭疽病的田间使用技术:在油茶炭疽病未发病或发病初期施用,推荐用量为有效成分用量216.67~406.25 mg/kg(制剂稀释倍数800~1 500倍),全株喷雾处理,施药2次,间隔7~10 d。通过开展苯醚甲环唑和嘧菌酯复配配方筛选及325 g/L苯甲·嘧菌酯悬浮剂对油茶炭疽病的防效研究,为该产品防治油茶炭疽病的推广应用提供理论依据。

Metabolomic modulations in a freshwater microbial community exposed to the fungicide azoxystrobin

An effective broad-spectrum fungicide,azoxystrobin(AZ),has been widely detected in aquatic ecosystems,potentially affecting the growth of aquatic microorganisms.In the present study,the eukaryotic alga Monoraphidium sp.and the cyanobacterium Pseudanabaena sp.were exposed to AZ for 7 days.Our results showed that 0.2–0.5 mg/L concentrations of AZ slightly inhibited the growth of Monoraphidium sp.but stimulated Pseudanabaena sp.growth.Meanwhile,AZ treatment effectively increased the secretion of total organic carbon(TOC)in the culture media of the two species,and this phenomenon was also found in a freshwater microcosm experiment(containing the natural microbial community).We attempted to assess the effect of AZ on the function of aquatic microbial communities through metabolomic analysis and further explore the potential risks of this compound.The metabonomic profiles of the microcosm indicated that the most varied metabolites after AZ treatment were related to the citrate cycle(TCA),fatty acid biosynthesis and purine metabolism.We thereby inferred that the microbial community increased extracellular secretions by adjusting metabolic pathways,which might be a stress response to reduce AZ toxicity.Our results provide an important theoretical basis for further study of fungicide stress responses in aquatic microcosm microbial communities,as well as a good start for further explorations of AZ detoxification mechanisms,which will be valuable for the evaluation of AZ environmental risk.

农药登记与农药减量的相关分析

为明确农药登记与农药减量途径的关系,本文对中国农药信息网上农药信息进行了检索和分析。结果表明:当前农药登记数据在不同作物上差异极大,主要集中在水稻和小麦等大面积种植作物上,而一些具有地方特色的小宗作物上登记农药品种极少;在防治中选择不同农药及剂型可有效减少农药使用量。以登记农药数据较多的水稻纹枯病为例,噻呋酰胺的推荐制剂剂量低于嘧菌酯,远低于井冈霉素等用量较大的杀菌剂;使用噻呋酰胺和嘧菌酯混剂并不能减少单位面积农药使用量,但使用混剂其有效成分用量要低于单独使用单剂时的农药使用量。科学选择登记农药或可成为开展农药减量增效工作的一条重要途径。

嘧菌酯在杨梅中的残留行为及膳食暴露风险评估

建立嘧菌酯在杨梅中的残留分析方法,考察嘧菌酯在杨梅中的储藏稳定性,通过开展50%嘧菌酯水分散粒剂在杨梅树上1年(2018年)6地的田间试验,明确嘧菌酯在杨梅上的残留特征及膳食风险。杨梅样品中嘧菌酯经乙腈提取,碱性氧化铝净化,超高效液相色谱串联质谱(UPLC-MS/MS)检测,外标法定量。结果表明,在0.001~0.05 mg·L^(-1)范围内,嘧菌酯在溶剂及基质中的峰面积与其对应的质量浓度间线性关系均良好,R 2≥0.9991。当添加质量分数为0.01~30.0 mg·kg^(-1)时,嘧菌酯在杨梅中添加回收率为90%~98%,相对标准偏差(RSD)为1.8%~7.9%,定量限(LOQ)为0.01 mg·kg^(-1),该方法能用于检测嘧菌酯在杨梅中的残留量。杨梅中嘧菌酯在冷冻储藏条件下较为稳定,在≤-18℃储藏条件下杨梅样品储藏650 d,其降解率低于14.3%。田间试验结果表明,嘧菌酯在杨梅上降解较快,其消解符合一级动力学方程,半衰期为2.2~5.0 d。按照300 mg·kg^(-1)(制剂用药量:1667倍液)对杨梅树施用50%嘧菌酯水分散粒剂2次,施药间隔10 d,最后一次施药后20、25、30 d,杨梅中嘧菌酯的残留量分别为0.012~0.57、<0.010~0.52、<0.010~0.28 mg·kg^(-1)。嘧菌酯的普通人群国家估算每日摄入量(national estimated daily intake,NEDI)是6.1114 mg,风险商(risk quotient,RQ)为48.5%,对一般人群健康风险较低。

45%苯并烯氟菌唑·嘧菌酯WG的高效液相色谱分析方法

建立同时测定45%苯并烯氟菌唑·嘧菌酯水分散粒剂中有效成分的液相色谱定量分析方法。使用Poroshell 120 EC-C_(18)色谱柱,柱温30℃,检测波长220 nm,以体积比60∶40乙腈-0.1%磷酸水体系为流动相,流速1 mL/min,测定样品中苯并烯氟菌唑和嘧菌酯的含量。苯并烯氟菌唑和嘧菌酯的线性相关系数(R2)均为0.999 9,标准偏差分别为6.86%和5.32%,变异系数分别为0.46%和0._(18)%,平均回收率分别为99.49%和99._(18)%。该方法简单高效、精密度高、分离效果好,可用于45%苯并烯氟菌唑·嘧菌酯水分散粒剂的定量分析。

嘧菌酯与硒代蛋氨酸复合暴露对斑马鱼胚胎及仔鱼的发育毒性

为探究嘧菌酯与硒代蛋氨酸复合暴露后对水体生物早期发育的影响,采用半静态试验法,测定了等毒性配比的嘧菌酯和硒代蛋氨酸二元混合体系复合暴露对水生模式生物斑马鱼胚胎及仔鱼的发育毒性及对相关酶活性的影响。结果表明:经不同质量浓度的嘧菌酯和硒代蛋氨酸(0.1+0.2、0.25+0.5、0.5+1.0和1.0+2.0 mg/L)(其中硒代蛋氨酸按硒元素的质量计,下同)复合暴露后,胚胎出现自主运动次数减少、孵化率降低、死亡率增加及心率下降现象,同时仔鱼体长受到显著抑制,且呈现明显的时间-剂量-效应关系;与对照组相比,在嘧菌酯和硒代蛋氨酸不同质量浓度(0.0005+0.001、0.005+0.01和0.05+0.1 mg/L)复合暴露下,斑马鱼仔鱼体内过氧化氢酶(CAT)活性显著降低,且高浓度复合暴露组(0.05+0.1 mg/L)的抑制作用最显著(P<0.01),而对超氧化物歧化酶(SOD)活性则无显著影响;与对照组相比,高浓度复合暴露组显著抑制了线粒体呼吸链复合体Ⅲ的活性(P<0.05),而其余浓度复合暴露组差异不显著。研究结果表明,经嘧菌酯与硒代蛋氨酸不同质量浓度复合暴露(0.1+0.2、0.25+0.5、0.5+1.0和1.0+2.0 mg/L)后,会对斑马鱼胚胎及仔鱼发育产生毒性效应,但在目前自然水体环境实际浓度水平下,除了抑制CAT活性外,尚不会产生其他毒性效应。以上研究结果可以为水体环境中嘧菌酯和硒代蛋氨酸浓度监测及复合暴露的生态风险评估提供数据支撑。

吡唑醚菌酯和嘧菌酯在铁皮石斛中的残留及其对黄酮含量的影响

为了解吡唑醚菌酯和嘧菌酯在铁皮石斛中的残留动态及吡唑醚菌酯和嘧菌酯对铁皮石斛中黄酮含量的影响,通过盆栽试验,设置了吡唑醚菌酯推荐低剂量(T1)、吡唑醚菌酯推荐高剂量(T2)、嘧菌酯推荐低剂量(T3)、嘧菌酯推荐高剂量(T4)和空白对照(CK)5个处理,采用QuEChERS-液相色谱-串联质谱法和紫外分光光度计检测法,测定铁皮石斛中吡唑醚菌酯和嘧菌酯的残留量和黄酮含量.结果表明:(1)建立的方法准确度及灵敏度良好,平均回收率为88.85%~117.50%,相对标准偏差为1.75%~13.92%,满足铁皮石斛中吡唑醚菌酯和嘧菌酯残留检测要求.(2)通过盆栽试验发现,吡唑醚菌酯和嘧菌酯在铁皮石斛中消解速率较慢,半衰期分别为110.45~145.45d和68.42~170.39d.90d时,T1和T2处理组在铁皮石斛中消解率和残留量分别为45.65%、5.23mg·kg^(-1)和40.70%、7.65mg·kg^(-1);T3和T4处理组在铁皮石斛中消解率和残留量分别为61.23%、2.51mg·kg^(-1)和36.56%、5.50mg·kg^(-1).(3)通过对90d铁皮石斛样品中黄酮含量的检测发现,吡唑醚菌酯和嘧菌酯处理在短时间内可显著提高铁皮石斛中黄酮含量,随着时间延长黄酮含量趋于稳定.

五种杀菌剂对烟草立枯病菌的生物活性

由立枯病丝核菌引起的烟草立枯病是我国烟草苗床上危害最严重的病害之一。本研究评价了5种杀菌剂(嘧菌酯、啶酰菌胺、氟啶胺、丙环唑和嘧霉胺)对立枯丝核菌菌丝生长、菌核形成和萌发的影响,以及其对烟草立枯病的防治效果。结果表明:立枯丝核菌菌丝对氟啶胺和嘧菌酯的敏感性高于丙环唑和啶酰菌胺,而对嘧霉胺的敏感性较低;嘧菌酯对菌核形成的抑制作用强于丙环唑、氟啶胺、啶酰菌胺和嘧霉胺;5种杀菌剂对立枯丝核菌菌核萌发均无抑制作用。在离体烟叶的保护活性方面,12.5和50 mg/L的嘧菌酯和啶酰菌胺对立枯病的保护作用优于氟啶胺、丙环唑和嘧霉胺;在治疗活性方面,50和200 mg/L的嘧菌酯的治疗作用优于其他4种杀菌剂。因此,供试的5种杀菌剂中嘧菌酯最适合用于烟草立枯病的防治。

应用GC-MS测定葡萄中的5种农药残留

酿酒葡萄是河北昌黎的主要水果种植品种,由于受海洋气候的影响,当地空气湿热,葡萄病害十分严重,因而农药使用十分频繁,为了评价其农药残留水平,我们采用丙酮提取,凝胶分离,硅胶小柱净化,GC-MS的选择离子方式检测对采集的葡萄样品进行5种农药(百菌清、精甲霜灵、苯醚甲环唑、嘧菌酯、高效氯氟氰菊酯)的残留分析.……

基于光气化反应的嘧菌酯合成研究

为了研究嘧菌酯绿色经济的合成方法,以4-氯-6-甲氧基嘧啶与水杨酰胺作原料,经醚化反应、光气化反应得到关键中间体2-((6-氯嘧啶-4-基)氧基)苯甲腈,再与2-(2-羟基苯基)-3,3-二甲氧基丙酸甲酯经醚化、脱甲醇反应得到目标产物嘧菌酯。结果表明,新合成方法总收率达80.4%,嘧菌酯含量达98%,产物及中间体结构经核磁确证。与现有生产工艺相比,新方法克服了副产物4-氯-6-甲氧基嘧啶量大,操作复杂,收率低等缺陷,具有绿色环保、原料易得、收率高、成本低廉等优点,适合工业化生产。

苯醚甲环唑和嘧菌酯在华南地区设施内外番茄中的残留及消解动态

采用超高效液相色谱-质谱法,研究了苯醚甲环唑和嘧菌酯在设施内外番茄中消解动态及其残留量,结合气象因子对产生残留差异的原因进行了分析。样品中的苯醚甲环唑和嘧菌酯经乙腈提取,乙二胺氮丙基硅烷(PSA)、石墨化碳(GCB)净化,UPLC-MS/MS检测;结果表明:苯醚甲环唑、嘧菌酯在设施中的消解速率均慢于其在露地中的,苯醚甲环唑在露地和设施内番茄中的半衰期分别是3.4和8.0 d,嘧菌酯在露地和设施内番茄中的半衰期分别是2.9和13.3 d。两种农药均是在设施内残留量高于露地番茄中的,而温度和降雨可能是引起农药在设施内外蔬菜上残留差异的主要因子。