Tobacco black shank caused by Phytophthora parasitica var.nicotianae(Breda de Hean)is one of the most serious diseases in tobacco growing,and few effective fungicides are available currently.The purpose of this study ...Tobacco black shank caused by Phytophthora parasitica var.nicotianae(Breda de Hean)is one of the most serious diseases in tobacco growing,and few effective fungicides are available currently.The purpose of this study was to assess the feasibility of using fluazinam to treat tobacco black shank disease.In vitro toxicities of fluazinam to 62 isolates of P.nicotianae were determined by mycelial growth rate method.The EC50 values ranged from 0.294 6 to 2.389 9 μg/mL with a mean of 1.084 0 μg/mL.The sensitivity distribution was unimodal,and there was no resistant isolate in P.nicotianae population.The carboxylic acid amide(CAA)fungicides were single-site in action and activity to oomycetes.The synergistic interactions were tested by Wadley method between fluazinam and dimethomorph,flumorph,mandipropamid,respectively.The mixture containing dimethomoph:Huazinam at 1:2 ratio showed additive actions,with the synergy ratio of 1.2.The mixture containing flumorph and fluazinam at 1:5 ratio had the highest synergy ratio(SR 2.07).Mandipropamid and fluazinam had an additive interaction and the proportion of 2:1 had the lowest EC50 value(0.020 7 μg/mL).This study demonstrated the sensitivity of P.nicotianae to fluazinam,and provided the experimental foundation to use fluazinam for tobacco black shank management.展开更多
To discover the fate of fluazinam after its application in pepper field, an efficient residual analytical method for determining fluazinam in pepper and soil was developed. The samples were extracted by acetone, clean...To discover the fate of fluazinam after its application in pepper field, an efficient residual analytical method for determining fluazinam in pepper and soil was developed. The samples were extracted by acetone, cleaned up by solid-phase extraction (SPE) florisil cartridge, and determined by gas chromatography with electronic capture detector (ECD). The recoveries ranged from 80 to 94.6%, with repeatability relative standard deviation ≤ 9.3% at spiking levels of 0.1-1 mg kg-1. The residue dynamics of fluazinam in pepper and soil were studied in a field plot. The experiment data showed that the half- lives of fluazinam in peppers and soils were 2.5-3.7 days and 1.2-4.2 days, respectively. When the pepper was treated by fluazinam 50% suspension concentrate (SC) at 495 g ha-1 4 times at 7-day intervals, the fluazinam in pepper on the 7th day after the last application was all below 0.06 mg kg-1, which was below the maximum residue limit (MRL) fixed in Korea (0.3 mg kg-1). It is implied that fluazinam in pepper is nonpersistent. The results suggested that fluazinam 50% SC should be used in a pepper field at most for 4 times, and the pre-harvest interval should be 7 days.展开更多
Fungicides are used to control pathogenic fungi of crop species,but they have also been shown to alter behavioral,life history and fitness related traits of nontarget insects.Here,we tested the fungicide effects on fe...Fungicides are used to control pathogenic fungi of crop species,but they have also been shown to alter behavioral,life history and fitness related traits of nontarget insects.Here,we tested the fungicide effects on feeding behavior,survival and physiology of the nontarget pest insect,the Colorado potato beetle(CPB)(Leptinotarsa decemlineata).Feeding behavior was studied by a choice test of adult beetles,which were allowed to choose between a control and a fungicide(fluazinam)treated potato leaf.Larval survival was recorded after 24 and 72 h exposure to control and fungicide-treated leaves with 2 different concentrations.The adults did not show fungicide avoidance behavior.Similarly,survival of the larvae was not affected by the exposure to fungicides.Finally,to understand the effects of fungicides at the physiological level(gene expression),we tested whether the larval exposure to fungicide alter the expression of 5 metabolic pathway and stress associated genes.Highest concentration and 72-h exposure caused upregulation of 1 cytochrome P450(CYP9Z14v2)and 1 insecticide resistance gene(Ldace1),whereas metabolic detoxification gene(Ugt1)was downregulated.At 24-h exposure,highest concentration caused downregulation of another common detoxification gene(Gs),while both exposure times to lowest concentration caused upregulation of the Hsp70 stress tolerance gene.Despite these overall effects,there was a considerable amount of variation among different families in the gene expression levels.Even though the behavioral effects of the fungicide treatments were minor,the expression level differences of the studied genes indicate changes on the metabolic detoxifications and stress-related pathways.展开更多
【目的】中国花生产区普遍发生冠腐病、根腐病和白绢病,严重影响花生生产。研究旨在比较并评价苯醚甲环唑与氟啶胺的微囊悬浮剂(microcapsule suspension,CS)和悬浮种衣剂(flowable concentrate for seed treatment,FS)对3种致病菌的毒...【目的】中国花生产区普遍发生冠腐病、根腐病和白绢病,严重影响花生生产。研究旨在比较并评价苯醚甲环唑与氟啶胺的微囊悬浮剂(microcapsule suspension,CS)和悬浮种衣剂(flowable concentrate for seed treatment,FS)对3种致病菌的毒力、包衣种子对花生的安全性以及对这3种病害的防治效果,以明确不同剂型制剂的安全性、持效期和施药方法。【方法】分别采用孢子萌发法和菌丝生长速率法比较苯醚甲环唑和氟啶胺的CS和FS对花生冠腐病菌、根腐病菌和白绢病菌的室内毒力,采用种子包衣法评价苯醚甲环唑和氟啶胺的两种制剂对花生的安全性,并进行田间药效试验。【结果】6%苯醚甲环唑FS、15%苯醚甲环唑CS、50%氟啶胺FS和12%氟啶胺CS对花生冠腐病菌孢子萌发的抑制率差异较大,其EC50分别为0.0503、0.4959、5.6141和46.5433 mg·L-1;对花生根腐病菌的EC50分别为0.5386、2.8604、0.3780和28.1665 mg·L-1;对花生白绢病菌的EC50分别为1.1435、3.2615、0.0951和3.8920 mg·L-1,表明微囊化后有效成分释放速度均显著减慢。20和25℃恒温下,与对照相比,苯醚甲环唑FS和CS 50、100、200 g a.i./100 kg种子、氟啶胺FS和CS 40、80和160 g a.i./100 kg种子包衣对花生出苗率、出苗时间、根长及鲜重、株高和茎叶鲜重均无明显影响。田间试验结果,所有处理的花生出苗时间和出苗率均无差异,6%苯醚甲环唑FS和15%苯醚甲环唑CS 100、200 g a.i./100 kg种子包衣对花生冠腐病、根腐病和白绢病的防效均达68.03%以上,12%氟啶胺CS 160 g a.i./100 kg种子对3种花生土传真菌病害的田间防效达74.97%以上,显著高于相同剂量的50%氟啶胺FS的防效。所有药剂处理均显著增加荚果产量,其中15%苯醚甲环唑CS 200 g a.i./100 kg种子处理的增产率最高,达7.22%—11.47%。【结论】6%苯醚甲环唑FS和15%苯醚甲环唑CS均在100、200 g a.i./100 kg种子,12%氟啶胺CS 160 g a.i./100 kg种子剂量下处理种子对花生安全,一次处理可以同时降低花生冠腐病、根腐病和白绢病的危害。展开更多
文摘Tobacco black shank caused by Phytophthora parasitica var.nicotianae(Breda de Hean)is one of the most serious diseases in tobacco growing,and few effective fungicides are available currently.The purpose of this study was to assess the feasibility of using fluazinam to treat tobacco black shank disease.In vitro toxicities of fluazinam to 62 isolates of P.nicotianae were determined by mycelial growth rate method.The EC50 values ranged from 0.294 6 to 2.389 9 μg/mL with a mean of 1.084 0 μg/mL.The sensitivity distribution was unimodal,and there was no resistant isolate in P.nicotianae population.The carboxylic acid amide(CAA)fungicides were single-site in action and activity to oomycetes.The synergistic interactions were tested by Wadley method between fluazinam and dimethomorph,flumorph,mandipropamid,respectively.The mixture containing dimethomoph:Huazinam at 1:2 ratio showed additive actions,with the synergy ratio of 1.2.The mixture containing flumorph and fluazinam at 1:5 ratio had the highest synergy ratio(SR 2.07).Mandipropamid and fluazinam had an additive interaction and the proportion of 2:1 had the lowest EC50 value(0.020 7 μg/mL).This study demonstrated the sensitivity of P.nicotianae to fluazinam,and provided the experimental foundation to use fluazinam for tobacco black shank management.
文摘To discover the fate of fluazinam after its application in pepper field, an efficient residual analytical method for determining fluazinam in pepper and soil was developed. The samples were extracted by acetone, cleaned up by solid-phase extraction (SPE) florisil cartridge, and determined by gas chromatography with electronic capture detector (ECD). The recoveries ranged from 80 to 94.6%, with repeatability relative standard deviation ≤ 9.3% at spiking levels of 0.1-1 mg kg-1. The residue dynamics of fluazinam in pepper and soil were studied in a field plot. The experiment data showed that the half- lives of fluazinam in peppers and soils were 2.5-3.7 days and 1.2-4.2 days, respectively. When the pepper was treated by fluazinam 50% suspension concentrate (SC) at 495 g ha-1 4 times at 7-day intervals, the fluazinam in pepper on the 7th day after the last application was all below 0.06 mg kg-1, which was below the maximum residue limit (MRL) fixed in Korea (0.3 mg kg-1). It is implied that fluazinam in pepper is nonpersistent. The results suggested that fluazinam 50% SC should be used in a pepper field at most for 4 times, and the pre-harvest interval should be 7 days.
基金supported by the Finish Cultural foundation and the Academy of Finland(Grant NO.308302 to LL and 322980 to MK).
文摘Fungicides are used to control pathogenic fungi of crop species,but they have also been shown to alter behavioral,life history and fitness related traits of nontarget insects.Here,we tested the fungicide effects on feeding behavior,survival and physiology of the nontarget pest insect,the Colorado potato beetle(CPB)(Leptinotarsa decemlineata).Feeding behavior was studied by a choice test of adult beetles,which were allowed to choose between a control and a fungicide(fluazinam)treated potato leaf.Larval survival was recorded after 24 and 72 h exposure to control and fungicide-treated leaves with 2 different concentrations.The adults did not show fungicide avoidance behavior.Similarly,survival of the larvae was not affected by the exposure to fungicides.Finally,to understand the effects of fungicides at the physiological level(gene expression),we tested whether the larval exposure to fungicide alter the expression of 5 metabolic pathway and stress associated genes.Highest concentration and 72-h exposure caused upregulation of 1 cytochrome P450(CYP9Z14v2)and 1 insecticide resistance gene(Ldace1),whereas metabolic detoxification gene(Ugt1)was downregulated.At 24-h exposure,highest concentration caused downregulation of another common detoxification gene(Gs),while both exposure times to lowest concentration caused upregulation of the Hsp70 stress tolerance gene.Despite these overall effects,there was a considerable amount of variation among different families in the gene expression levels.Even though the behavioral effects of the fungicide treatments were minor,the expression level differences of the studied genes indicate changes on the metabolic detoxifications and stress-related pathways.
文摘【目的】中国花生产区普遍发生冠腐病、根腐病和白绢病,严重影响花生生产。研究旨在比较并评价苯醚甲环唑与氟啶胺的微囊悬浮剂(microcapsule suspension,CS)和悬浮种衣剂(flowable concentrate for seed treatment,FS)对3种致病菌的毒力、包衣种子对花生的安全性以及对这3种病害的防治效果,以明确不同剂型制剂的安全性、持效期和施药方法。【方法】分别采用孢子萌发法和菌丝生长速率法比较苯醚甲环唑和氟啶胺的CS和FS对花生冠腐病菌、根腐病菌和白绢病菌的室内毒力,采用种子包衣法评价苯醚甲环唑和氟啶胺的两种制剂对花生的安全性,并进行田间药效试验。【结果】6%苯醚甲环唑FS、15%苯醚甲环唑CS、50%氟啶胺FS和12%氟啶胺CS对花生冠腐病菌孢子萌发的抑制率差异较大,其EC50分别为0.0503、0.4959、5.6141和46.5433 mg·L-1;对花生根腐病菌的EC50分别为0.5386、2.8604、0.3780和28.1665 mg·L-1;对花生白绢病菌的EC50分别为1.1435、3.2615、0.0951和3.8920 mg·L-1,表明微囊化后有效成分释放速度均显著减慢。20和25℃恒温下,与对照相比,苯醚甲环唑FS和CS 50、100、200 g a.i./100 kg种子、氟啶胺FS和CS 40、80和160 g a.i./100 kg种子包衣对花生出苗率、出苗时间、根长及鲜重、株高和茎叶鲜重均无明显影响。田间试验结果,所有处理的花生出苗时间和出苗率均无差异,6%苯醚甲环唑FS和15%苯醚甲环唑CS 100、200 g a.i./100 kg种子包衣对花生冠腐病、根腐病和白绢病的防效均达68.03%以上,12%氟啶胺CS 160 g a.i./100 kg种子对3种花生土传真菌病害的田间防效达74.97%以上,显著高于相同剂量的50%氟啶胺FS的防效。所有药剂处理均显著增加荚果产量,其中15%苯醚甲环唑CS 200 g a.i./100 kg种子处理的增产率最高,达7.22%—11.47%。【结论】6%苯醚甲环唑FS和15%苯醚甲环唑CS均在100、200 g a.i./100 kg种子,12%氟啶胺CS 160 g a.i./100 kg种子剂量下处理种子对花生安全,一次处理可以同时降低花生冠腐病、根腐病和白绢病的危害。
