Effects of pyraclostrobin on growth,oxidative stress,and gene expression in relation to stress and ATP-binding cassette transporters in Tetrahymena thermophila

Pyraclostrobin(PYR),a widely used fungicide,has negative effects on fish and algae,but its toxicity in protozoa remains unclear.In this study,the effects of PYR on the growth,oxidative stress,and gene expression related to stress and ATP-binding cassette(ABC)transporters in Tetrahymena thermophila were investigated.The result showed that the 96-h IC_(50)of PYR against T.thermophila was 17.2 mg/L.Moreover,PYR inhibited the growth of T.thermophila in concentration-or time-dependent manner.A morphological study revealed that the shape and size of T.thermophila changed,and damage of cell membrane surface was observed by scanning electron microscopy after 96 h of PYR exposure.The activities of superoxide dismutase(SOD)and catalase(CAT)increased throughout the experiment.In contrast,the glutathione(GSH)content was increased at 24 h and 48 h of exposure and decreased at 96 h.Moreover,a significant increase in malondialdehyde(MDA)level was observed in T.thermophila after96 h of exposure.Furthermore,PYR upregulated the HSP703,HSP705,GPx2,and ABAC15 gene expression in the 0.1–5-mg/L groups and downregulated the HSP704,HSP90,TGR,and ABCC52 mRNA levels at 96 h of exposure.These results suggest that PYR may exert adverse effects on T.thermophila by inducing oxidative stress and changing the gene expression related to ABC transporters and stress,which may enrich the understanding of the toxicity mechanism of PYR in aquatic organisms and provide reference data for aquatic ecological risk assessments.

甘蔗中吡唑醚菌酯残留量检测及膳食风险评估

研究甘蔗中吡唑醚菌酯残留检测方法,并对最终残留量进行长期膳食摄入和短期膳食摄入风险评估。样品中吡唑醚菌酯采用QuEChERS前处理方法进行提取,高效液相色谱-三重四极杆串联质谱法检测;长期和短期膳食摄入评估采用膳食摄入风险评估模型进行。甘蔗中吡唑醚菌酯残留量为0.267~0.888 mg/kg。吡唑醚菌酯的普通人群国家估算每日摄入量是1.83 mg,占日允许摄入量的97%左右。甘蔗中吡唑醚菌酯在儿童和成人的国家估算短期摄入量占短期参考剂量(acute reference dose,ARfD)均<100%。按该试验的施药方式进行施药时,甘蔗中吡唑醚菌酯的残留量对一般人群健康风险在可接受的范围内。

吡唑醚菌酯在冬枣中的残留消解及膳食风险评估

2021—2022年在河北黄骅开展了250 g/L吡唑醚菌酯乳油在冬枣中的规范残留田间试验,样品采用QuEChERS法净化,气相色谱-电子捕获检测器检测分析,得出吡唑醚菌酯在冬枣中的残留消解规律,并对其进行膳食风险评估。2年残留消解试验结果显示,吡唑醚菌酯在冬枣中的半衰期分别为9.86、11.8 d,消解规律符合一级动力学方程;最终残留试验结果显示,末次药后14~28 d,吡唑醚菌酯残留量为0.297~0.684 mg/kg,其中,末次药后21 d的残留试验中值为0.432 mg/kg。膳食风险评估得出风险商为0.62%,膳食摄入风险可接受。建议250 g/L吡唑醚菌酯乳油在冬枣上使用剂量为3000~4000倍液,每季最多施药3次,施药间隔期7 d,安全间隔期21 d。

氟吡菌酰胺和吡唑醚菌酯在葡萄上的残留及膳食风险评估

为明确氟吡菌酰胺和吡唑醚菌酯在葡萄上的残留风险,开展了一年十地的规范残留试验,建立了高效液相色谱法(HPLC)测定葡萄中氟吡菌酰胺和吡唑醚菌酯残留的分析方法。结果表明,在0.1~20.0 mg·L^(-1)范围内,氟吡菌酰胺和吡唑醚菌酯质量浓度与其峰面积均呈良好的线性关系,相关系数大于0.99。在0.05、0.50 mg·kg^(-1)和2.00 mg·kg^(-1)添加水平下,氟吡菌酰胺和吡唑醚菌酯在葡萄中的平均回收率分别为88.1%~112.3%和90.5%~101.5%,相对标准偏差(RSD)分别为3.1%~8.2%和3.5%~9.1%,检测方法定量限(LOQ)均为0.05 mg·kg^(-1)。采收间隔期为14 d,时葡萄中氟吡菌酰胺和吡唑醚菌酯的残留中值(STMR)分别为0.16 mg·kg^(-1)和0.12 mg·kg^(-1),最高残留值(HR)分别为1.44 mg·kg^(-1)和1.48 mg·kg^(-1)。葡萄中氟吡菌酰胺和吡唑醚菌酯对一般人群的长期膳食摄入风险的贡献率分别为0.142%和0.036%,短期膳食摄入风险商分别为7.8%和5.7%,对1~6岁儿童的短期膳食摄入风险商分别为19.6%和14.4%。研究表明,按照推荐剂量规范使用,氟吡菌酰胺和吡唑醚菌酯在葡萄中的残留量对1~6岁儿童和一般人群造成的健康风险处于安全水平。

改良QuEChERS方法结合高效液相色谱测定土壤中两种甲氧基丙烯酸酯类农药

旨在建立新疆、内蒙、黑龙江3种不同类型土壤中醚菌酯和吡唑醚菌酯含量的高效液相色谱法。采用改良的QuEChERS方法结合高效液相色谱,对样品中的吡唑醚菌酯及醚菌酯进行分离,外标法定量。结果表明:该方法在0.3~10.0 mg/L浓度范围内,线性关系良好,线性相关系数R2均大于0.9999,在不同添加水平下,吡唑醚菌酯与醚菌酯在新疆灰漠土中的平均回收率分别为98.03%~102.32%、100.33%~107.18%,相对标准偏差(RSD)分别为0.46%~0.87%、0.94%~1.67%;在黑龙江黑钙土中的平均回收率分别为100.40%~104.32%、90.83%~101.33%,RSD分别为0.47%~2.78%、1.35%~1.69%;在内蒙棕钙土中的平均回收率分别为100.04%~107.40%、96.90%~98.86%,RSD分别为0.77%~1.41%、1.08%~1.57%。该方法准确度和精密度符合农药残留分析的要求,适用于几种类型土壤中吡唑醚菌酯及醚菌酯含量的测定。

吡唑醚菌酯对斑马鱼早期生命阶段的亚致死效应研究

为明确吡唑醚菌酯对斑马鱼早期生命阶段的亚致死效应和慢性毒性,研究了不同浓度吡唑醚菌酯(0.328~32.0μg·L^(-1))长期暴露斑马鱼胚胎30 d后,对斑马鱼生长发育,以及氧化胁迫、能量代谢和肝脏能量代谢酶活等生化指标的影响。研究发现,吡唑醚菌酯暴露30 d后,5.12μg·L^(-1)吡唑醚菌酯能够显著降低斑马鱼仔鱼的体长,2.05、5.12和12.8μg·L^(-1)吡唑醚菌酯长期暴露后可以显著增加仔鱼的体质量,0.819、5.12和12.8μg·L^(-1)吡唑醚菌酯可以引起仔鱼肝脏不同程度的空泡化。此外,为了进一步明确吡唑醚菌酯对斑马鱼胚胎发育过程中的毒性效应,分别于暴露2 d、6 d、10 d、16 d和30 d测定斑马鱼胚胎/仔鱼体内的丙酮酸、葡萄糖、胆固醇、甘油三酯、游离脂肪酸含量,以及与氧化胁迫和肝脏代谢相关的酶活。在30 d暴露期间,吡唑醚菌酯对斑马鱼过氧化氢酶(CAT)活性总体呈现先降低再升高的趋势,对过氧化物歧化酶(SOD)和游离脂肪酸也有不同程度的影响,吡唑醚菌酯处理对斑马鱼体内丙酮酸含量总体呈现先降低后升高的趋势,对甘油三酯含量总体呈现降低的趋势,而吡唑醚菌酯对不同生长阶段斑马鱼体内的葡萄糖和总胆固醇合成有一定的诱导作用,暴露6 d和30 d时所有吡唑醚菌酯处理组鱼体内葡萄糖含量显著增加。此外,吡唑醚菌酯对斑马鱼早期生命阶段的碱性磷酸酶(AKP)活性有一定的诱导作用,对谷丙转氨酶(GPT)和谷草转氨酶(GOT)活性也有不同程度的影响。研究表明,吡唑醚菌酯可能通过诱导氧化应激、干扰葡萄糖、总胆固醇等糖类和脂类的合成,影响斑马鱼体内抗氧化系统和能量代谢,引起肝脏能量代谢相关酶的活性改变进一步干扰能量代谢,进而导致斑马鱼早期生命阶段的生长和肝脏发育异常。

On the Bacteriostatic Activity of Bacillus subtilis and Pyraclostrobin as Well as Their Mixtures to Grape Anthracnose and the Field Disease Control Efficiency

[Objective] To screen out the biological compound bactericides for grape anthracnose, reduce and replace the use of chemical pesticide. [Methods] The de- termination on the indoor bacteriostatic activity of different proportions of Bacillus subtilis and pyraclostrobin to grape anthracnose was carried out, and mycelial growth rate method was adopted to determine the toxicity of Bacillus subtilis and pyraclostrobin as well as their 5 mixtures to grape anthracnose. [Results] The EC50 of Bacillus subtilis and pyraclostrobin as well as their mixture combinations of 1：1, 1：2, 1：3, 1：4 and 1：5 to grape anthracnose were respectively 1.969 8, 1.527 4, 1.373 2, 1.294 8 and 1.247 3 μg/ml; the synergistic coefficients （SR） of the 5 mix- ture combinations to grape anthracnose were 1.70, 1.25, 1.13, 1.12 and 1.12, re- spectively, in which the synergistic effect of 1：1 was the largest. The indoor biologi- cal activity of pyraclostrobin（EC50 was 1.054 0μg/ml） was higher than that of Bacil- lus subtilis（EC50 was 15.017 5 μg/ml）. 50 d after the agentia（before the harvesting）, the investigation results showed that 1 000-fold dilution, 1 500-fold dilution and 2 000- fold dilution as well as each single dosage of 20% pyraclostrobin .200×10^8 cfu/g Bacillus subtili wettable powder all had better control efficiency to grape anthracnose after fruit setting and before bagging, in which the treatments of high concentration and middle concentration were higher than the treatments of low concentration and two single dosages： the highest control efficiency of high concentration was 90.03%, which was higher than all other treatments; the control efficiency of middle concen- tration was 87.01%, which was higher than that of low concentration and each sin- gle dosage; the control efficiency of low concentration was 84.11%, which was high- er than 1 000-fold dilution of 1 000×10^8 cfu/g Bacillus subti/i wettable powder （the control efficiency was 64.60%） and 2 000-fold dilution of 250 g/L Bacillus subti/i wettable powder （the control efficiency was 81.07%）. In addition, each treatment al- so had better control efficiency to other cluster diseases, such as white rot, etc., and the control efficiency was almost the same as that of anthracnose. [Conclusion] It was suggested that the prevention concentration of 20% pyraclostrobin .200×10^8 cfu/g Bacillus subtili wettable powder to grape anthracnose after fruit setting and before bagging was 1 000-fold - 2 000-fold dilution.

叶菌唑及其复配剂对河南省假禾谷镰孢菌的抑制活性及对小麦茎基腐病的室内防效

主要由假禾谷镰孢菌Fusarium pseudograminearum引起的小麦茎基腐病是严重影响小麦产量的真菌病害。为明确叶菌唑对河南省小麦茎基腐病菌的抑制活性,测定了叶菌唑对从供试的219株菌株中随机选取的3株菌株(JY2208、HB2201和XC2116)不同发育阶段的毒力,以及叶菌唑分别与咪鲜胺、氰烯菌酯、氟啶胺和咯菌腈按质量比5:1、3:1、1:1、1:3和1:5复配对菌株JY2208的联合毒力;采用胚芽鞘接种法测定了叶菌唑及其复配剂对小麦茎基腐病的室内防效。结果显示:叶菌唑对3株假禾谷镰孢菌JY2208、HB2201和XC2116菌株菌丝生长、分生孢子产生、孢子萌发及芽管伸长的EC50值分别为(0.0397±0.0035)、(0.9549±0.1152)、(0.6114±0.0393)及(0.0235±0.0015)μg/mL;叶菌唑对219株假禾谷镰孢菌菌丝生长的EC50值范围为0.0207~0.0839μg/mL,平均EC50值为(0.0406±0.0114)μg/mL,敏感性频率分布呈连续单峰曲线,可作为河南省假禾谷镰孢菌对叶菌唑的敏感性基线。叶菌唑与咪鲜胺、氰烯菌酯、氟啶胺以及咯菌腈复配的增效系数(SR)范围为0.51~2.32,不同组合、不同配比的复配剂均表现为相加作用或增效作用,表明叶菌唑可以与咪鲜胺、氰烯菌酯、氟啶胺、咯菌腈复配使用。其中,当叶菌唑与氟啶胺按质量比5:1复配时,增效作用最强,SR为2.32。8%叶菌唑悬浮剂与50%氟啶胺悬浮剂按有效成分质量比5:1复配,在80μg/mL剂量下,对小麦茎基腐病的室内防治效果达100%。该研究结果可为小麦茎基腐病的防控提供依据。

Synergism and Field Efficacy of Mixed Preparations of Pyraclostrobin and Tebuconazole to Glomerella cingulata

[Objective] This study was conducted to screen high-efficient low-toxicity new compound preparation for control of Glomerella cingulata. [Method] The toxicity of pyraclostrobin, tebuconazole and their mixed preparations to Glomerella cingulata was determined by mycelial growth rate method, and their control effects on Glomerella cingulata were evaluated by field efficacy test. [Result] The mixed preparations of pyraclostrobin and tebuconazole at mass ratios of 5：1, 3：1, 1：1, 1：3 and 1：5 exhibited ECso values to mycelial growth of Glomerella cingulata of 0.612 9, 0.530 1, 0.232 6, 0.232 8 and 0.329 6 iJg/ml, respectively; and the 5 preparations exhibit- ed synergistic coefficients （SRs） to Glomerella cingulata of 1.29, 1.33, 2.29, 1.84 and 1.22, respectively, and among them, the preparation with mass ratio of 1：1 showed the highest synergism. The field efficacy test showed that the field control effects of 1 000 times, 2 000 times and 3 000 times dilutions of 25% pyraclostrobin-tebuconazole suspension, 5 000 times dilution of 430 g/L tebuconazole suspension and 2 000 times dilution of 250 g/L pyraclostrobin EC were 91.54%, 90.80%, 82.88%, 76.43% and 74.10%, respectively. [Conclusions] Therefore, the mixed preparations of pyraclostrobin and tebuconazole showed remarkable synergism on control of Glomerella cingulata, and preparation with the mixing ratio of 1：1 exhibited the most significant synergism on Glomerella cingulata. For soaking treatment to fruit clusters with 1 000-2 000 times dilution of 25% pyraclostrobin .tebuconazole suspension, the field efficacy to Glomerella cingulata was over 90%.

Control Effects of Bacillus subtilis DJ-6 and Pyraclostrobin Alone and in Combination Against Fusarium oxysporum

[Objective] This study was conducted to screen a synergistic biological fungicide complex to control Fusarium wilt, reducing the use of chemical pesticides. [Method] The inhibitory effects of Bacil us subtilis DJ-6 and pyraclostrobin alone or in combination at five ratios against Fusarium oxysporum were detected by mea-suring mycelium growth rate in laboratory tests. The growth promotion and disease control effect of combined or single use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000, 1∶2 000 and 1∶3 000 dilutions were detected in field trials. [Result] The EC50 values of combined use of B. subtilis DJ-6 and pyra-clostrobin at ratios of 1∶1, 1∶2, 1∶3, 1∶4 and 1∶5 against F. oxysporum were 5.311 5, 4.008 6, 3.570 6, 3.350 9 and 3.218 9 μg/ml, with the synergistic ratios （SR） of 2.28, 1.77, 1.53, 1.64, 1.11, among which the synergetic effect at 1∶1 was the best. The fungicidal activity of pyraclostrobin was greater than that of B. subtilis DJ-6 in laboratory tests. Field trials revealed that al the 1∶1 000, 1∶2 000 and 1∶3 000 dilu-tions of 20% pyraclostrobin·2×1011 cfu/g B. subtilis DJ-6 WP in combination, 1∶1 000 dilution of 1 ×1012 cfu/g B. subtilis DJ-6 WP and 1∶2 000 dilution of 250 g/L pyra-clostrobin EC promoted the growth of strawberry by increasing plant height, leaf petiole, leaf blade area and stem diameter. Among them, the treatments with 1∶1 000 and 1∶2 000 of 20% pyraclostrobin · 2×1011 cfu/g B. subtilis DJ-6 WP in combina-tion had better effects than other treatments. The control effects of al the treat-ments were measured 30 and 80 d after fungicide application. The control effects of 1∶1 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combina-tion were up to 100% and 93.11%, which were higher than those in al other treat-ments. The second highest control effects were found in the treatment with 1∶ 2 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination, they were 92.49% and 86.49%, higher than those in other treatments except the 1∶1 000 dilution of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 in combination. The control effects of 1∶3 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination were 82.61% and 72.42%, higher than those in treatment with 1∶1 000 dilution of 1×1012 cfu/g B. subtilis DJ-6 WP, but lower than those in treat-ment with 1∶2 000 dilution of 25% pyraclostrobin EC. [Conclusion] Al the results re-vealed that the combination use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000 to 1∶2 000 dilution had better control effect against strawberry Fusarium wilt.

噻呋酰胺与吡唑醚菌酯复配对烟草靶斑病菌的抑制活性及对烟草靶斑病的室内防效

由立枯丝核菌Rhizoctonia solani引起的靶斑病是近年来烟草主要叶部病害之一,严重降低了烟叶的产量和品质。目前生产中登记用于防治烟草靶斑病的药剂仅有井冈霉素,且该药剂对病害的田间治疗效果较差。为筛选对烟草靶斑病具有优良防效的化学药剂,本研究采用菌丝生长速率法建立了立枯丝核菌对噻呋酰胺和吡唑醚菌酯的敏感性基线,发现两者对立枯丝核菌菌丝生长均有较强的抑制作用。通过联合毒力测定发现两者复配后均表现为相加或增效作用,其中,噻呋酰胺与吡唑醚菌酯按质量比1:1复配,增效作用最明显,增效系数达2.5以上,可显著抑制病原菌菌核形成。采用喷雾接种法测定了该复配比作为保护剂和治疗剂使用时对烟草靶斑病的防效,发现其具有优异的室内防效。本研究结果表明,噻呋酰胺与吡唑醚菌酯按质量比1:1复配在田间防治烟草靶斑病中具有较好的应用前景。

基于液相色谱-质谱联用法检测芒果中44种农药及其代谢物残留量的风险分析

以芒果为样品,采用QuEChERS液相色谱-质谱联用法(LC-MS/MS)对芒果中44种农药及其代谢物残留量进行测定,65.0%的全果中检出农药残留。吡唑醚菌酯、苯醚甲环唑在全果中检出率最高,分别为52.5%和35.0%。按照我国制定的最大残留限量标准(MRL),吡唑醚菌酯在全果中存在超标现象,不合格率20%。利用检出的数据进行统计分析,浅析芒果中农药残留量的现状与风险,对加强农药监督管理以及指导种植户合理规范使用农药提出建议,为市场监督管理提供参考。

防治草莓炭疽病的增效药剂组合筛选及效果评价

采用菌丝生长速率法测定了5种杀菌剂对草莓炭疽病菌的室内毒力,将2种抑菌效果好的杀菌剂复配筛选增效配比,并在温室验证了其防治效果和对草莓植株的影响。结果表明,吡唑醚菌酯和苯醚甲环唑对草莓炭疽病菌均表现出良好的抑菌效果,EC 50值分别为0.80 mg/L和6.33 mg/L;吡唑醚菌酯和苯醚甲环唑2个配比的增效系数分别是0.70和1.51,表现为相加或增效作用,其中2∶1配比的共毒系数最大。在设施条件下,移栽时用30%苯醚甲环唑·吡唑醚菌酯悬浮剂(吡唑醚菌酯和苯醚甲环唑2∶1)稀释1500~2000倍蘸根处理,对草莓炭疽病具有良好的防治效果,同时对草莓生长无负面影响。

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。

吡唑醚菌酯关键中间体1-(4-氯苯基)-3-吡唑醇的合成工艺研究

1-(4-氯苯基)-3-吡唑醇是甲氧基丙烯酸酯类杀菌剂吡唑醚菌酯的关键中间体。以对氯苯胺为原料,采用动态管连续法合成对氯苯肼盐酸盐,与丙烯酸乙酯环化反应得到中间体1-(4-氯苯基)-3-吡唑酮,然后用双氧水低温光催化连续氧化得到1-(4-氯苯基)-3-吡唑醇,对不同反应条件下的实验结果进行了分析,优化反应条件为:重氮化物料停留时间为40 min、反应温度5℃、搅拌速率150 r/min,环合反应温度为60℃,在UVA光源下进行氧化反应,产品总收率大于88.0%,纯度大于98.0%。该方法重氮化反应和氧化反应本质安全,原材料价廉易得,产品收率和纯度高,操作简单,适合于工业化生产。

吡唑醚菌酯羟胺关键中间体的催化加氢新工艺

2-[(N-对氯苯基)-3-吡唑氧基甲基]硝基苯(简称吡唑醚)还原制备吡唑醚菌酯羟胺关键中间体的工业化常规工艺是使用雷尼镍为催化剂,水合肼做氢源,该方法羟胺选择性高,但过程中使用的雷尼镍、水合肼均为易爆品,存在较大安全隐患,且反应过程难控制。催化加氢原子利用率高,但催化加氢工业化制备羟胺仍是难点。采用铂碳催化加氢工艺,可实现吡唑醚原料转化率>99%,吡唑醚菌酯羟胺关键中间体选择性>99%,且工艺条件温和,化学工艺本质更安全。

2种施药方式对防治苹果黑星病药剂减量的效果

为探索防治苹果黑星病化学药剂减量控害的施药方式,以30%苯甲·吡唑酯悬浮剂为防治药剂,采用延长喷药间隔期和推迟首次喷药期2种施药方式进行田间试验。2020—2022年的试验结果表明,延长喷药间隔期15、20、25 d,对苹果黑星病的防效分别为70.73%~83.51%、73.02%~89.10%、67.35%~91.48%;推迟首次喷药期,80%花谢后进行第1次喷施、80%花谢后15 d进行第1次喷施和80%花谢后30 d进行第1次喷施对苹果黑星病的防效分别为71.89%~82.06%、66.08%~88.87%、62.84%~89.55%。因此,在确保对苹果黑星病取得明显防治效果的前提下,可将喷药间隔期延长至20 d或将首次喷药期推迟至80%花谢后15 d进行,2种施药方式可分别减少喷药4次和2次,化学药剂减量控害效果显著。

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.

Pyraclostrobin-loaded poly(lactic-co-glycolic acid) nanospheres: Preparation and characteristics

We used poly(lactic-co-glycolic acid)(PLGA) as a carrier polymer for pyraclostrobin-loaded nanospheres. Using the ultrasound emulsification-solvent evaporation method, the physicochemical characteristics and release properties of the pyraclostrobin-loaded nanospheres were studied by dialysis. The optimal nanospheres prepared had a diameter of 0.6 μm, an active ingredient loading of 17.2%, and a loading rate of 89.7%. Infrared spectroscopy data and differential scanning calorimetry revealed that pyraclostrobin was successfully embedded in the carrier PLGA, and photostability tests indicated enhanced ultraviolet resistance of pyraclostrobin-loaded PLGA nanospheres nanospheres. Release property testing indicated that smaller particles had a faster release rate. Nanospheres also had a faster release rate in slightly acidic and slightly basic environments than in a neutral condition. Agitated nanospheres had a faster release rate than immobile nanospheres. The cumulative release kinetics of pyraclostrobin-loaded nanospheres was consistent with the first order kinetic equation and the Weibull equation.

吡唑醚菌酯与氟环唑复配对小麦叶锈病的防治效果及对小麦的安全性

为筛选适用于小麦叶锈病防治的化学药剂,本研究选取吡唑醚菌酯和氟环唑及二者不同比例复配组合,采用喷雾接种法,测定了吡唑醚菌酯和氟环唑单剂及其不同复配比例在作为保护剂使用时对小麦叶锈病的室内防治效果,并测定了室内筛选确定的最佳比例复配药剂对小麦的安全性及对小麦叶锈病的田间防治效果。室内防效试验显示:吡唑醚菌酯、氟环唑及二者不同比例复配对小麦叶锈病病斑扩展有强烈的抑制作用,其中吡唑醚菌酯的抑制作用更强,其EC_(50)值为0.01μg/mL。联合毒力评价表明:所有复配组合均表现出协同相加作用,吡唑醚菌酯·氟环唑质量比50∶133复配时增效系数(SR)最大,为1.50。室内及田间防治试验表明:在所设浓度梯度范围内,防效与浓度呈正相关;在有效成分120 g/hm^(2)剂量下,26%吡唑醚菌酯·氟环唑悬浮剂(SC)的田间防效为85.12%,优于各自单剂处理。安全性评价结果显示:所有处理均能保证不同品种小麦正常生长,未发生药害现象。研究表明,吡唑醚菌酯·氟环唑复配对小麦叶锈病有很好的防治效果,可为生产上防治小麦叶锈病和科学用药提供理论依据。