[Objectives]This study was conducted to investigate the joint toxicity of fungicides on aquatic ecosystems.[Methods]Using zebrafish as a model organism,an LC-MS/MS simultaneous detection method was established for flu...[Objectives]This study was conducted to investigate the joint toxicity of fungicides on aquatic ecosystems.[Methods]Using zebrafish as a model organism,an LC-MS/MS simultaneous detection method was established for fluxapyroxad and pyraclostrobin(with detection limits at ng/L level),and their acute toxicity,joint toxicity and toxic mechanisms were systematically evaluated.[Results]The toxicity of pyraclostrobin(96 h-LC 50=0.052 mg/L)to zebrafish was approximately 25.8 times higher than that of fluxapyroxad(96 h-LC 50=1.34 mg/L).Joint toxicity evaluation using the fixed-ratio ray design revealed that six of the seven mixture ratios exhibited additive effects(AI=0.62-1.47),while the 8:1 ratio showed antagonism(AI=2.14).The analysis of toxicity mechanisms indicated that both fungicides induced oxidative stress,lipid peroxidation,and cellular damage through inhibition of mitochondrial complex III and II,respectively,with pyraclostrobin inducing more pronounced hepatic MDA elevation(2.56-fold)and antioxidant enzyme inhibition.Ecological risk assessment demonstrated that fluxapyroxad posed moderate risk(RQ=0.16-0.90),while pyraclostrobin posed moderate to high risk(RQ=0.56-3.56),and crustaceans faced the highest risk.[Conclusions]This study elucidated the mechanism underlying toxicity differences due to distinct mitochondrial targets,providing a scientific basis for fungicide management.展开更多
[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 ...[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.展开更多
[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 an...[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.展开更多
[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 preparatio...[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%.展开更多
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 ...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.展开更多
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 p...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.展开更多
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 relat...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.展开更多
Pyraclostrobin,a quinone outside inhibitor(QoI)fungicide,has been registered to control apple tree Valsa canker(AVC)caused by Valsa mali in China.However,there is no data available regarding the resistance risk of V.m...Pyraclostrobin,a quinone outside inhibitor(QoI)fungicide,has been registered to control apple tree Valsa canker(AVC)caused by Valsa mali in China.However,there is no data available regarding the resistance risk of V.mali to pyraclostrobin.In this study,the sensitivities of 120 V.mali isolates to pyraclostrobin were detected.The isolates were collected from apple orchards with no application of pyraclostrob at six provinces in China during 2013–2015,and showed similar sensitivity to pyraclostrobin.The EC_(50) values of these 120 V.mali isolates to pyraclostrobin ranged from 0.0014 to 0.0240μg/mL,indicating an excellent inhibitory efficacy of pyraclostrobin to the pathogen.The EC_(50) values were distributed as a unimodal curve with a mean value of 0.0091μg/mL,and the mean EC_(50) displayed correlation with geographic location.Meanwhile,three pyraclostrobin-resistant mutants(PR mutants)of V.mali were obtained using fungicide adaption method,with a resistance factor(RF)of 41.0,56.8 and 22.0,respectively.The mutants showed a stable resistance to pyraclostrobin after 10 transfers on pyraclostrobin-free medium.Comparing with the corresponding parental isolates,the hyphal growth,mycelial dry weight and pathogenicity of PR mutants were significantly reduced,but the number of propagules showed no significant difference.More importantly,no cross-resistance of PR mutants to pyraclostrobin,tebuconazole,difenoconazole,imazalil and thiophanate-methyl was detected.In conclusion,V.mali showed a moderate risk to pyraclostrobin,and pyraclostrobin could be used as an alternative fungicide to control AVC in the field in China.展开更多
为明确吡唑醚菌酯在大豆加工过程中的残留变化特征,本研究建立了气相色谱-串联质谱(Gas Chromatography Tandem Mass Spectrometry,GC-MS/MS)检测方法,系统分析大豆原料及其加工产物(豆皮、大豆仁、豆饼、压榨毛油、豆粕、浸出毛油和成...为明确吡唑醚菌酯在大豆加工过程中的残留变化特征,本研究建立了气相色谱-串联质谱(Gas Chromatography Tandem Mass Spectrometry,GC-MS/MS)检测方法,系统分析大豆原料及其加工产物(豆皮、大豆仁、豆饼、压榨毛油、豆粕、浸出毛油和成品油)中吡唑醚菌酯的残留特征。在黑龙江和安徽两地大豆田开展250 g·L^(-1)吡唑醚菌酯乳油的规范农药登记残留田间试验,结合加工因子(PF)校正的膳食风险评估模型,揭示其在不同加工环节的迁移规律及风险水平。结果表明:大豆经压榨和浸出两种方式加工后压榨毛油和浸出毛油中吡唑醚菌酯均存在浓缩效应,加工因子在3.21~6.70之间,且浸出毛油的加工因子较压榨毛油高。大豆压榨毛油和浸出毛油精炼后成品油的加工因子在0.52~0.69之间,均低于1,与精炼过程中白土的吸附有关。国家估计普通人群吡唑醚菌酯在大豆加工前后的每日摄入量(NEDI)分别为0.7393和0.7555 mg,风险系数分别为39.1%和40.0%。在良好农业规范(Good Agriculture Practices,GAP)条件下施用250 g·L^(-1)吡唑醚菌酯乳油及大豆加工后对消费者的健康风险较低,加工因子校正评估模型更切合实际风险水平。展开更多
基金Supported by New Project of Postgraduate Scientific Research Innovation in 2024(ZSCX2024Y21).
文摘[Objectives]This study was conducted to investigate the joint toxicity of fungicides on aquatic ecosystems.[Methods]Using zebrafish as a model organism,an LC-MS/MS simultaneous detection method was established for fluxapyroxad and pyraclostrobin(with detection limits at ng/L level),and their acute toxicity,joint toxicity and toxic mechanisms were systematically evaluated.[Results]The toxicity of pyraclostrobin(96 h-LC 50=0.052 mg/L)to zebrafish was approximately 25.8 times higher than that of fluxapyroxad(96 h-LC 50=1.34 mg/L).Joint toxicity evaluation using the fixed-ratio ray design revealed that six of the seven mixture ratios exhibited additive effects(AI=0.62-1.47),while the 8:1 ratio showed antagonism(AI=2.14).The analysis of toxicity mechanisms indicated that both fungicides induced oxidative stress,lipid peroxidation,and cellular damage through inhibition of mitochondrial complex III and II,respectively,with pyraclostrobin inducing more pronounced hepatic MDA elevation(2.56-fold)and antioxidant enzyme inhibition.Ecological risk assessment demonstrated that fluxapyroxad posed moderate risk(RQ=0.16-0.90),while pyraclostrobin posed moderate to high risk(RQ=0.56-3.56),and crustaceans faced the highest risk.[Conclusions]This study elucidated the mechanism underlying toxicity differences due to distinct mitochondrial targets,providing a scientific basis for fungicide management.
基金Supported by the Independent Innovation Fund Project of Agricultural Science and Technology in Jiangsu Province[CX(14)2056]Agricultural Science&Technology Supporting Program of Zhenjiang City(NY2014005)Science and Technology Innovation Items of Jurong City(NY2013026)~~
文摘[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.
基金Supported by Agricultural Science and Technology Research and Development Program of Jiangsu Province(BE2012378)Six Talent Peaks Project of Jiangsu Province(2013-NY-001)Agricultural Science and Technology Research and Development Program of Zhenjiang City(NY2014029)~~
文摘[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.
基金Supported by Jiangsu Agricultural Science and Technology Independent Innovation Fund(CX(14)2056)Science & Technology Specific Project for Enriching People and Strengthening County Economy in China(BN20156222)~~
文摘[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%.
文摘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.
基金supported by the National Key R&D Program of China (2017YFD0200301, 2016YFD0200500)
文摘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.
基金the Key Scientific Research Projects of Henan Province to College Youth Backbone Teacher(No.2021118)the National Key Research and Development Program of China(No.2021YFE0112000)。
文摘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.
基金supported by the National Key R&D Program of China(2016YFD0201100).
文摘Pyraclostrobin,a quinone outside inhibitor(QoI)fungicide,has been registered to control apple tree Valsa canker(AVC)caused by Valsa mali in China.However,there is no data available regarding the resistance risk of V.mali to pyraclostrobin.In this study,the sensitivities of 120 V.mali isolates to pyraclostrobin were detected.The isolates were collected from apple orchards with no application of pyraclostrob at six provinces in China during 2013–2015,and showed similar sensitivity to pyraclostrobin.The EC_(50) values of these 120 V.mali isolates to pyraclostrobin ranged from 0.0014 to 0.0240μg/mL,indicating an excellent inhibitory efficacy of pyraclostrobin to the pathogen.The EC_(50) values were distributed as a unimodal curve with a mean value of 0.0091μg/mL,and the mean EC_(50) displayed correlation with geographic location.Meanwhile,three pyraclostrobin-resistant mutants(PR mutants)of V.mali were obtained using fungicide adaption method,with a resistance factor(RF)of 41.0,56.8 and 22.0,respectively.The mutants showed a stable resistance to pyraclostrobin after 10 transfers on pyraclostrobin-free medium.Comparing with the corresponding parental isolates,the hyphal growth,mycelial dry weight and pathogenicity of PR mutants were significantly reduced,but the number of propagules showed no significant difference.More importantly,no cross-resistance of PR mutants to pyraclostrobin,tebuconazole,difenoconazole,imazalil and thiophanate-methyl was detected.In conclusion,V.mali showed a moderate risk to pyraclostrobin,and pyraclostrobin could be used as an alternative fungicide to control AVC in the field in China.
文摘为明确吡唑醚菌酯在大豆加工过程中的残留变化特征,本研究建立了气相色谱-串联质谱(Gas Chromatography Tandem Mass Spectrometry,GC-MS/MS)检测方法,系统分析大豆原料及其加工产物(豆皮、大豆仁、豆饼、压榨毛油、豆粕、浸出毛油和成品油)中吡唑醚菌酯的残留特征。在黑龙江和安徽两地大豆田开展250 g·L^(-1)吡唑醚菌酯乳油的规范农药登记残留田间试验,结合加工因子(PF)校正的膳食风险评估模型,揭示其在不同加工环节的迁移规律及风险水平。结果表明:大豆经压榨和浸出两种方式加工后压榨毛油和浸出毛油中吡唑醚菌酯均存在浓缩效应,加工因子在3.21~6.70之间,且浸出毛油的加工因子较压榨毛油高。大豆压榨毛油和浸出毛油精炼后成品油的加工因子在0.52~0.69之间,均低于1,与精炼过程中白土的吸附有关。国家估计普通人群吡唑醚菌酯在大豆加工前后的每日摄入量(NEDI)分别为0.7393和0.7555 mg,风险系数分别为39.1%和40.0%。在良好农业规范(Good Agriculture Practices,GAP)条件下施用250 g·L^(-1)吡唑醚菌酯乳油及大豆加工后对消费者的健康风险较低,加工因子校正评估模型更切合实际风险水平。
