福·腈菌可湿性粉剂的高效液相色谱分析

本文采用反相高效液相色谱法,以甲醇为溶剂,甲醇+水+冰乙酸为流动相,C18柱和紫外检测器,定量测定福·腈菌可湿性粉剂中福美双和腈菌唑的含量.结果表明福美双和腈菌唑的标准偏差分别为0.07和o.05;变异系数分别为0.42%、0.07%;回收率分别为99.1%、99.7%,线性相关系数为0.9998,1.0000.     

甲·福可湿性粉剂的高效液相色谱法

本文论述了在同一液谱条件下测定７０％甲·福可湿性粉剂中的甲基硫菌灵、福美双含量的方法。该方法采用反相色谱柱分离，三元混合流动相进行洗脱，采用紫外可变波长检测器进行检测，以外标法定量。甲基硫菌灵和福美双变异系数分别为０．９３％、１．４０％；回收率分别为９８．２５～１０２．０％、９８．４６～１０１．０％；线性相关系数分别为０．９９８７、０．９９９９。     

甲.福可湿性粉剂的高效液相色谱法

本文论述了在同一液谱条件下测定７０％甲．福可湿性粉剂中的甲基硫菌灵,福美双含量的方法,该方法采用反相色谱柱分离,三元混合流动相进行洗脱,采用紫外可变波长检测器进行检测,以外标法定量,甲基硫菌灵和福美双变异系数为０．９３％,１．４０％,回收率分别为９８．２５～１０２．０％９８．４６－１０１．０％,线性相关系数分别为０．９９８７,０．９９９９。     

小麦白粉病菌对喹氧灵和苯菌酮的敏感基线及药剂的生物活性

采用离体叶段法,分别测定了从河北、河南、湖北、陕西和四川5省分离的53个小麦白粉病菌单孢菌株对苯菌酮和喹氧灵的敏感性,并分析了白粉病菌对三唑酮和苯菌酮以及喹氧灵之间的 交互抗性。结果表明:小麦白粉病菌群体对苯菌酮和喹氧灵的平均EC50值分别为(0.001 9±0.000 6) 和(0.013 1±0.002 0) mg/L,苯菌酮比喹氧灵具有更高的抑菌活性;小麦白粉病菌对三唑酮和苯菌酮与喹氧灵之间均不存在交互抗性(R2值分别为0.102 6和0.491 9);室内盆栽试验结果显示:接种前1 d和接种后1d施药,苯菌酮和喹氧灵对小麦白粉病的保护与治疗作用防效分别为92.21%、84.25%和82.43%、70.25%,表明这2种药剂不仅具有优异的保护作用,同时还具有较好的治疗作用。     

甲基硫菌灵、福美双混合制剂的分析方法研究

本文介绍用反相高效液谱法,以甲醇为溶剂,异丙醇＋水为流动相,Ｃ１８为填料的色谱柱和紫外检测器,测定甲基硫菌灵、福美双的含量。     

甲基硫菌灵,福美双混合制剂的分析方法研究

本文介绍反相高效液谱法，以甲醇为溶剂，异丙醇＋水为流动相，Ｃ１８为填料的色谱柱和紫外检测器，测定甲基硫菌灵，福美双的含量。     

不同杀菌剂不同施用次数对小麦赤霉病的防效

在种植小麦赤霉病高感品种襄麦1321的田间进行施药试验。调查5种药剂:50%多菌灵可湿性粉剂、25%氰烯菌酯悬浮剂、25%咪鲜胺乳油、70%甲基硫菌灵可湿性粉剂、30%福美双可湿性粉剂分别喷施1~4次处理对小麦赤霉病的防治效果。结果表明,施药24h内降雨对氰烯菌酯的防效影响最大;咪鲜胺防效相对较差,不同施用次数的病指防效为42.51%~64.55%;多菌灵、甲基硫菌灵和氰烯菌酯施用3~4次的处理防效较高,病指防效均达70%以上;福美双的防效随施用次数增多而提高,施用4次的处理防效也达70%以上。     

70%百·福可湿性粉剂的高效液相色谱分析方法

本文采用高效液相色谱法,以SymmetryC18为固定相,以甲醇+水为流动相,用紫外检测器在230nm对70%百·福可湿性粉剂中的百菌清和福美双进行分离和定量分析。结果表明:百菌清、福美双的线性相关系数分别为0.99996、0.99999;标准偏差分别为0.0829、0.0798;变异系数分别为0.41%、0.16%;平均回收率分别为99.21%、101.01%。     

21％聪唑禾草灵·乙菝氟草醚乳油液相色谱分祈

本文采用高效液相色谱法,以C18柱为固定相,甲醇+水为流动相,用236nm紫外检测器定量测定唑禾草灵、乙羧氟草醚混剂的有效成分含量。本方法的变异系数分别为0.06%、0.40%;标准偏差分别为0.009、0.032;平均回收率分别为99.13%、100.05%;线性相关系数分别为0.9993、0.9998。     

高效液相色谱串联质谱测定水果和蔬菜中的甲基硫菌灵和多菌灵残留

建立了同时测定水果和蔬菜中甲基硫菌灵、多菌灵的液相色谱串联质谱法。选取3种代表性水果鸭梨、苹果、西瓜和3种蔬菜菜花、芦笋、胡萝卜进行研究,先用乙腈提取,经石墨化碳氨基复合柱净化后,用C18柱分离,以乙腈和水为流动相进行梯度洗脱,四极杆串联质谱采用电喷雾正离子和多反应监测模式检测。结果表明:甲基硫菌灵在0.05~0.8μg/mL质量浓度范围内,多菌灵在0.005~0.08μg/mL质量浓度范围内线性关系良好,相关系数均不小于0.99;甲基硫菌灵、多菌灵的检出限分别为10μg/kg和1μg/kg。在3个不同的加标水平下,多菌灵的回收率在85%~106%之间,甲基硫菌灵的回收率在78~89%之间,相对标准偏差为分别为6.7%~7.6%和8.7%~9.8%。该方法能有效检测出多种水果和蔬菜中甲基硫菌灵、多菌灵的残留量,且稳定性好,结果可靠。     

Survey of Fungicide Sensitivity in Colletotrichum gloeosporioides from Different Avocado and Mango Production Areas in South Africa

Pre-harvest fungicidal treatments aimed at reducing inoculum levels in the field include copper oxychloride and benomyl. Pre-harvest applications of benomyl are currently restricted if used on fruit destined for certain export markets. Isolates of Colletotrichum gloeosporioides collected during a three-year market survey were used to determine the incidence of resistance to benomyl, thiabendazole and prochloraz using an in vitro assay. A total of 17.7% of all isolates tested were resistant to benomyl, of which 8.5% were highly and 9.2% moderately resistant. Isolates from certain production areas were less sensitive to benomyl and thiabendazole, and mango isolates were generally more sensitive than avocado isolates. No isolates were resistant to thiabendazole or prochloraz.     

Survey of benomyl resistance in Fusavium species on winter wheat in England and Wales in 1986

In 1986, samples from 109 winter wheat crops in England and Wales were examined for benomyl resistance in Fusarium species. Of the 704 isolates obtained, 581 were identified as Fusarium nivale, of which 92.1 % were resistant to benomyl. Of the remaining isolates, 82 were identified as F. avenaceum, 40 as F. culmorum and one as F. poae; none of these isolates were resistant to benomyl. The vast majority of isolates of Fusarium spp. were obtained from superficial nodal or internodal lesions on the stems.     

High pressure liquid chromatography of benzimidazolcs

A laboratory-assembled high pressure liquid chromatograph with variable wavelength ultraviolet detector is described. The chromatography of the systemic fungicides benomyl, thiabendazole, thiophanate, related fungicides and benzimidazoles (13 compounds in all) is described using reverse phase and adsorption systems. Temperature affects reverse phase systems but not adsorption systems. Use of a variable wavelength detector increases sensitivity and selectivity. High pressure liquid chromatography (h.p.l.c.) has been applied to measurements of the solubility of benomyl and carbendazim in water and the degradation of benomyl in solution. Use of h.p.l.c. to measure benzimidazole residues awaits the development of methods of avoiding interference by substances extracted from crops and soils.     

Influence of artificial rainfall and washing on the benomyl and thiophanate-methyl residue content in lettuce

Experiments have been carried out to investigate the influence of artificial rainfall, applied during the growing season of lettuce in a glasshouse, and washing of the sample prior to analysis on the residue content of the crop treated with the systemic fungicides benomyl and thiophanate-methyl. The results show that if artificial rainfall is applied, treatment with a threefold dose of thiophanate-methyl, compared to benomyl, results in about the same residue content at harvest time. Applying artificial rainfall during the growing season leads to a residue level on the average 54.7% lower for benomyl and 60.2% for thiophanate-methyl compared to no sprinkling. If the sample is thoroughly rinsed with water prior to analysis the figures obtained are 34.6% with and 39.3% without artificial rainfall for benomyl and 56.9 and 71.3% respectively for thiophanate-methyl. The combined effect of both treatments is a residue content of 70.4 % less for benomyl and 88.8 % for thiophanate-methyl.     

Inhibition of cutinase and prevention of fungal penetration into plants by benomyl—A possible protective mode of action

Cutinase purified from Fusarium solani f. sp. pisi was effectively inhibited by the fungicide benomyl. This irreversible inhibition was shown to be caused by the reaction of n-butylisocyanate, a breakdown product of benomyl, with the active serine in the enzyme. Methyl-2-benzimidazolecarbamate (MBC), the other breakdown product of benomyl, had no cutinase inhibitory activity. The fungicidal action of benomyl was measured by a bioassay using pea stems with or without intact cuticular and cell wall barriers. Benomyl prevented infection of Pisum sativum by conidia of F. solani f. sp. pisi only on intact pea stems with 50% efficiency at 7 μM, but was without effect on wounded stems or when benomyl (up to 50 μM) was applied 24 hr after inoculation with spores. Both MBC and benomyl strongly inhibited mycelial growth with 50% inhibition at 2 μM indicating a toxic mode of action. The prevention of fungal infection on only intact stem surfaces was established, however, with a fungal strain which was relatively tolerant to the toxic effect of these fungicides. With this strain complete protection was obtained at 5 μM benomyl which caused only 30% inhibition of growth. These results suggest that benomyl at low concentrations prevented fungal penetration and thus infection probably through inhibition of cutinase. It is also shown that treatment of cutin with n-butylisocyanate made it resistant to cutinase action.     

Metabolism of 2-aminobenzimidazole and benzimidazole in melon plants

Melon plants grown in a liquid nutrient solution were separately treated either with benomyl, 2-aminobenzimidazole (2-AB), or benzimidazole (BZ), and after 60 days each compound had decomposed into significant concentrations of metabolites, those from 2-AB and BZ corresponding to the metabolites from benomyl. This supported the following postulated metabolic pathway for benomyl in melon plants: benomyl → carbendazim → 2-AB→BZ Involvement of the other identified metabolites of benomyl (2-aminobenzonitrile, o-phenylenediamine, aniline, and the conjugates of carbendazim and 2-AB) cannot be proposed unequivocally. In the extracts from plants treated with 2-AB or BZ, new and unidentified metabolites have also been observed using gas-liquid chromatography (g.l.c.).     

Control of brown blotch of Bambara groundnut with garlic extract and benomyl

Field trials were conducted over two seasons to evaluate the efficacy of a water extract of garlic either alone, or in combination with reduced quantities of Benlate (benomyl 50% a.i., WP), for control of brown blotch of bambara groundnut caused byColletotrichum capsici. Results obtained showed that garlic extract has potential for control of brown blotch under field conditions, although it is not so effective as benomyl. Combining the extract with lower dosages of benomyl, however, appeared to have a synergistic effect. Consequently, the treatment comprising half the recommended dosage of benomyl (0.3 gl ⁻¹) combined with 1% (w/v) garlic extract was as effective as the full dosage of the fungicide which gave complete control of the disease. http://www.phytoparasitica.org posting Feb. 2, 2003.     

Further studies of the inheritance of benomyl resistance in Venturia pirina isolated from pear orchards in Israel

Fourteen single-spore cultures of benomyl-resistant Venturia pirina were isolated from pear scab lesions at four sites in Israel. According to the ability of the isolates to germinate and grow at varying benomyl concentrations, four levels of resistance were determined in vitro : three isolates with low resistance (LR) grew at 0.5 but not at 5 μg/ml benomyl: five moderately resistant (MR) isolates grew at 5 but not at 50 μg/ml benomyl: five highly resistant (HR) isolates grew at 50 μg/ml but their hyphae were curled: and one isolate with very high resistance (VHR) grew unaffected at 50 μg/ml benomyl. The difference between the HR and the VHR phenotypes was clearly shown on medium amended with N -(3.5-dichlorophenyl) carbamate (MDPC): only the VHR isolate showed negative cross-resistance to 1 μ g/ml MDPC. whereas HR isolates grew unaffected. Crosses between resistant isolates and sensitive wild types, as well as between different resistant isolates, showed that the various levels of resistance are conferred by four allelic mutations that constitute a polymorphic series at a single locus.     

Incidence of benomyl and iprodione resistance in isolates of Botrytis cinerea in tomato crops in England and Wales in 1986

In 1986, mass-mycelial isolates of Botrytis cinerea from 67 tomato crops in England and Wales were examined for benomyl and iprodione resistance. Of the 706 isolates obtained, 62.7% were resistant to benomyl at 2μg/ml and 43.2% were resistant to iprodione at 2 μg/ml. Iprodione resistance persisted in the absence of a dicarboximide spray programme. The incidence of benomyl resistance has not decreased since the last survey in 1984 in spite of a considerable reduction in the use of benzimidazole fungicides. There were no clear indications that the use of dichlofluanid influenced the incidence of benomyl or iprodione resistance. Disease control was poorer in crops with a higher incidence of iprodione resistance.