戊菌唑原药的高效液相色谱分析

为寻求操作简便、快速地测定戊菌唑中有效成分含量,建立了高效液相色谱法测定戊菌唑含量的定量分析方法.采用SB-C18 HPLC色谱柱,以甲醇/水(80∶20)为流动相,检测测波选择230nm.结果表明:方法的标准偏差为0.24,变异系数为1.36%,相关系数r=0.9998,平均回收率为99.7%.本方法检验实际样品中戊菌唑的含量,结果重现性好.     

戊菌唑在黄瓜和土壤中的残留

为探明戊菌唑在黄瓜中的安全性,采用气相色谱-电子捕获器法对戊菌唑在江苏南京、北京和吉林长春3个试验点黄瓜和土壤中的残留消解动态和最终残留进行了研究。结果表明,在0.01 mg/kg、0.10 mg/kg和1.00 mg/kg 3个添加水平下,戊菌唑在黄瓜中的添加回收率为82.5%～94.2%,相对标准偏差为4.8%～7.5%;在土壤中平均回收率为81.2%～93.2%,相对标准偏差为6.2%～9.1%;戊菌唑在黄瓜和土壤中的最低检测浓度均为0.01 mg/kg。戊菌唑在3个试验点黄瓜中的半衰期为1.6～1.9 d,在土壤中的半衰期为1.8～2.3 d。戊菌唑按低剂量(57.0 g/hm2,a.i.)或高剂量(85.5 g/hm2,a.i.)施药2次或3次,在最后一次施药1 d、3 d和5 d后采收,黄瓜中戊菌唑的残留量均低于0.080 mg/kg。按试验推荐施药剂量和次数施用戊菌唑,参照CAC、欧盟或日本制订的黄瓜中戊菌唑的最大残留限量标准(0.1 mg/kg),所采收的黄瓜是安全的。     

Mobility of four triazole fungicides in two Indian soils

The sorption and downward mobility of four triazole fungicides, triadimefon, hexaconazole, penconazole and propiconazole, were studied in two Indian soils (New Delhi and Punjab). Punjab soil (organic carbon 0.4%) showed greater sorption capability for triazole fungicides than New Delhi soil (organic carbon 0.5%) and the order of sorption of triazoles in both soils was: penconazole > hexaconazole > propiconazole > triadimefon. Fungicides were more mobile in New Delhi soil columns than Punjab soil columns, and increasing the total water flux from 1 pore volume to 3 pore volumes further increased the transport to lower down in the column. Triadimefon showed maximum mobility while penconazole was the least mobile triazole fungicide. After percolating 3 pore volumes of water, triadimefon leached down to 25-30 cm depth in New Delhi soil and 15-20 cm in Punjab soil columns. Downward mobility of triazole fungicides was in order of their sorption results.     

戊菌唑200克/升水乳剂高效液相色谱分析方法研究

本文采用高效液相色谱法,以乙腈＋磷酸溶液为流动相,使用以ZORBAX Extend-C18、5μm为填料的不锈钢柱和二极管阵列检测器,在220nm波长下对200克/升戊菌唑水乳剂进行分离和定量分析。结果表明,该分析方法的线性相关系数为0.999 8;标准偏差为0.095;变异系数为0.48%;平均回收率为100.1%。     

Sensitivity of Podosphaera aphanis isolates to DMI fungicides: distribution and reduced cross‐sensitivity

BACKGROUND: Management of strawberry powdery mildew, Podopshaera aphanis (Wallr.), requires numerous fungicide treatments. Limiting epidemics is heavily dependent on sterol demethylation inhibitors (DMIs) such as myclobutanil or penconazole. Recently, a noticeable reduction in the efficacy of these triazole fungicides was reported by strawberry growers in France. The goal of this study was to investigate the state of DMI sensitivity of French P. aphanis and provide tools for improved pest management. RESULTS: Using leaf disc sporulation assays, sensitivity to myclobutanil and penconazole of 23 isolates of P. aphanis was monitored. Myclobutanil EC₅₀ ranged from less than 0.1 to 14.67 mg L^?1 and for penconazole from 0.04 to 4.2 mg L^?1. A cross‐analysis and a Venn diagram showed that there was reduced sensitivity and a positive correlation between the less sensitive myclobutanil and penconazole isolates; 73.9% of isolates were less sensitive to a DMI and 47.8% exhibited less sensitivity to both fungicides. CONCLUSION: The results show that sensitivity to myclobutanil and, to a lesser extent, penconazole has become less efficient in strawberry powdery mildew in France. Therefore, urgent action is required in order to document its appearance and optimise methods of control. Copyright © 2009 Society of Chemical Industry     

Positive effects of Penconazole on growth of Brassica napus under drought stress

The aim of the present study was to compare the effects of drought on some physiological and biochemical parameters and to assess the inducing effects of Penconazole (PEN) on drought tolerance in two cultivars (RGS003 as a drought tolerant and Sarigol as a drought sensitive) of canola. Plants were treated with various PEG concentrations (0, 5, 10, and 15%) without or with PEN (15 mg l^?1). Decrease in fresh weight (FW) and dry weight (DW) in Sarigol under drought was higher than that of RGS003. Surprisingly, PEN reversed prominently the negative effects of drought on FW and DW in RGS003. Concomitantly, PEN treatment decreased malondialdehyde content in RGS003 under drought. Moreover, higher content of proline in RGS003 under all drought levels could be considered as a factor for drought tolerance of this cultivar. Superoxide dismutase (SOD), catalase (CAT) and Polyphenol oxidase (PPO) activities were induced by PEN in both cultivars under drought. Inducing effects of PEN on phenylalanine ammonia lyase and thyrosine ammonia lyase activities decreased by increasing of drought levels in both cultivars. In summary, PEN alleviated the negative effects of drought in RGS003 cultivar by inducing activities of SOD, CAT and PPO and proline content comparing to Sarigol.