50%醚菌酯干悬浮剂对香蕉尾孢菌叶斑病的毒力测定与防治试验

香蕉尾孢菌叶斑病是香蕉上的重要病害,每年夏秋季节在华南蕉区普遍发生,危害严重.2003～2004年进行新型杀菌剂50%醚菌酯干悬浮剂对香蕉尾孢菌的毒力测定和防治叶斑病药效试验,结果表明,50%醚菌酯干悬浮剂对香蕉尾孢菌的抑菌效果明显,对香蕉叶斑病有良好的防治效果,对香蕉安全;第3次施药后15 d,50%醚菌酯干悬浮剂1 500倍的防治效果达到82.67%,显著优于对照药剂25%敌力脱乳油1 500倍的防效,建议在生产上推广使用.     

醚菌酯对百合鳞茎青霉病的控制

采用醚菌酯浸泡兰州百合青霉病的研究结果表明:在25~100 mg/L处理浓度范围内,醚菌酯可明显降低损伤接种圆弧青霉(Penicillium cyclopium)在百合鳞片体内的扩展,其中以50 mg/L处理的效果最好,100 mg/L和125mg/L处理均造成了一定程度的药害.不同温度处理结果显示,40℃的醚菌酯处理效果优于其他温度处理,50℃和60℃处理均产生了严重的烫伤.损伤接种与药物处理的间隔时间也会对处理结果造成一定的影响.     

醚菌酯的高效液相色谱分析

采用反相高效液相色谱法对醚菌酯进行了定量分析研究,流动相为甲醇-乙腈-水(体积比为50∶20∶30),使用ODS C18为填料的不锈钢柱和具可变波长的紫外检测器。该方法的平均回收率为99.95%,变异系数为0.242 7%,标准偏差为0.235 8。     

Bioregulatory Effects of the Fungicidal Strobilurin Kresoxim-methyl in Wheat (Triticum aestivum)

Apart from its fungicidal effect, the strobilurin kresoxim-methyl (BAS 490 F) was found to induce physiological and developmental alterations in wheat (Triticum aestivum L.) which are seen in connection with improved yield. In a series of biotests including heterotrophic maize and photoautotrophic algal cell suspensions, duckweed, isolated mustard shoots and germinating cress seeds, kresoxim-methyl showed a similar response pattern to standard auxins (e.g. indol-3-ylacetic acid, IAA; 2-(1-naphthyl)acetic acid, α-NAA). Auxin-like activity of kresoxim-methyl was also found when stem explants of tobacco were cultured on a hormone-free medium. Kresoxim-methyl stimulated shoot formation, particularly at 10^-7 M . The same effect was induced by 10^-8 M IAA. The determination of phytohormone-like substances in shoots of wheat plants foliar-treated with 7×10^-4 M kresoxim-methyl revealed only slightly changed levels of endogenous IAA, gibberellins and abscisic acid. In contrast, the contents of dihydrozeatin riboside-type cytokinins increased to 160% of the control, while trans-zeatin riboside- and isopentenyladenosine-type cytokinins remained nearly unchanged. The most remarkable alterations were the reductions in 1-aminocyclopropane-1-carboxylic acid (ACC) levels and ethylene formation which were demonstrated in intact plants, leaf discs and the shoots of wheat subjected to drought stress. Kresoxim-methyl affected the induction of ACC synthase activity which converts S-adenosyl-methionine to ACC in ethylene biosynthesis. In shoots from foliar-treated wheat plants, 10^-4 M kresoxim-methyl inhibited stress-induced increases in endogenous ACC synthase activity, ACC levels and ethylene formation by approximately 50%. Reductions in ACC synthase activity and ACC levels of 30% were also obtained at low concentrations of α-NAA (10^-6 M ). In contrast, ACC synthase activity in vitro was not influenced by adding the compounds. In wheat leaf discs, the inhibiting effect of kresoxim-methyl, α-NAA and IAA on ethylene formation was accompanied by delayed leaf senescence, characterized by reduced chlorophyll loss. However, in contrast to kresoxim-methyl which showed only inhibitory activity on ethylene synthesis over a wide range of concentrations applied, the auxins stimulated ethylene production at high concentrations of about 10^-4 M . The inhibition of ethylene biosynthesis by kresoxim-methyl, together with an increase in endogenous cytokinins could explain the retardation of senescence and the intensified green leaf pigmentation in wheat exposed to this strobilurin. © 1997 SCI.     

醚菌酯·己唑醇40%悬浮剂高效液相色谱定量分析

建立了在同一色谱条件下测定混剂中醚菌酯和己唑醇含量的方法。采用250mm×4.60mm(i.d.)phenomenex Gemini C18柱分离,以甲醇∶水(75∶25,V/V)为流动相,在220nm紫外检测波长下,经保留时间定性确证,峰面积外标法进行定量分析。结果表明,醚菌酯和己唑醇的线性相关系数分别为0.9998、0.9996;变异系数分别为0.32%、0.39%;平均回收率分别为99.15%、100.28%。     

葡萄炭疽病菌对甲基硫菌灵、戊唑醇和醚菌酯的敏感性检测

采用菌丝生长法检测了78株采自浙江省杭州、嵊州和嘉兴 3地的葡萄炭疽病菌 Colletotrichum gloeosporioides 对甲基硫菌灵、戊唑醇和醚菌酯的敏感性。结果表明:供试病菌已对甲基硫菌灵产生了严重的抗药性,抗性频率为51.3%,且均为高水平抗药性菌株;78个供试菌株对戊唑醇的EC50值在0.04～21.56 μg/mL之间,平均为1.63 μg/mL,其中L-58菌株的敏感性最低,EC50值为21.6 μg/mL。旁路氧化酶抑制剂水杨肟酸(SHAM)处理对醚菌酯抑制葡萄炭疽病菌菌丝生长的活性表现出明显的增效作用:无SHAM存在时,醚菌酯抑制菌丝生长的EC50(EC50Q)值在0.03～436.55 μg/mL之间,平均为27.77 μg/mL;当SHAM的处理质量浓度为50 μg/mL时,EC50(EC50Q+S)值在0.01～15.20 μg/mL 之间,平均为4.40 μg/mL。旁路氧化的相对贡献值 F 最低为0,最高为155.47,平均为20.09。     

30%醚菌酯悬浮剂在黄瓜和土壤中的残留降解行为及安全使用技术

[目的]评价30%醚菌酯悬浮剂在设施栽培黄瓜上使用后的残留行为及环境安全性。[方法]参照《农药残留试验准则》,通过气相色谱法检测分析黄瓜中醚菌酯含量,研究了30%醚菌酯悬浮剂在黄瓜上的残留动态。[结果]醚菌酯在银川、长沙、哈尔滨黄瓜中的半衰期分别为2.8~3.1、2.4~3.7、2.1~5.1 d,施药3、5、7 d黄瓜中醚菌酯的残留量均低于0.500 0 mg/kg,未超出国家限量标准。[结论]建议设施栽培条件下,最高制剂用药量270 g.a.i/ha(制剂0.09 g/m2),最多施药3次,安全间隔期3~5 d。     

黄瓜与土壤中醚菌酯残留的气相分析方法研究

[目的]建立黄瓜和土壤中醚菌酯残留检测方法。[方法]用乙腈提取黄瓜和土壤样品,经弗罗里硅柱净化后用气相色谱ECD检测器检测。[结果]在醚菌酯添加水平为0.05、0.20、0.50 mg/kg 3个浓度时,黄瓜中回收率为80.2%~114.0%,变异系数为2.1%~5.8%;土壤中回收率为95.1%~106.5%,变异系数为3.1%~7.3%,醚菌酯的最小检出量为2.5×10-2ng,最低检出浓度为2.5μg/kg。[结论]该方法灵敏度高、检测限低、重现性好,完全能够满足黄瓜和土壤中醚菌酯残留的检测要求。     

Laboratory tests to determine the intrinsic toxicity of four fungicides and two insecticides to the predacious miteAgistemus fleschneri

Laboratory tests showed that trifloxystrobin (Flint® 50WG), myclobutanil (Nova® 40WP), flusilazole (Nustar® 50DF) and kresoxim-methyl (Sovran® 50WG) were harmless to adult mites and did not affect adversely the reproductive capacity ofAgistemus fleschneri (Summers) (Acari: Stigmaeidae). Among the insecticides evaluated, by the same technique, λ-cyhalothrin (Warrior T® 12%) and imidacloprid (Admire® 24%) were also non-toxic.     

Differential responses of germinating Venturia inaequalis conidia to kresoxim-methyl

A new class of agricultural fungicides derived from strobilurins act as respiration inhibitors by binding to mitochondrial cytochrome b. The effects of the strobilurin, kresoxim-methyl, on conidia germination, mycelial growth and the protection of apple leaves from scab development were investigated for two isolates of Venturia inaequalis randomly selected from a culture collection. Inhibition of mycelial growth required relatively high doses of kresoxim-methyl (ED₅₀=1 μg ml^-1) for both isolates. In comparison, germination of conidia was highly sensitive for one of the isolates (ED₅₀=0·005 μg ml^-1), while the level of inhibition achieved for the second isolate was 60-fold less (ED₅₀=0·3 μg ml^-1). As deduced from identical sequences of cytochrome b cDNAs prepared from both isolates, the different responses of germinating conidia to kresoxim-methyl were not caused by differences in the sequence of cytochrome b as the target site for strobilurin action. Strong synergistic effects of salicylhydroxamic acid on kresoxim-methyl inhibitory potency suggested that the reduced kresoxim-methyl sensitivity observed for germinating conidia was caused by interference of the alternative respiratory pathway with inhibitor action. However, this mechanism of target site circumvention in germinating conidia had no adverse effects on the protection of apple leaves from scab infection by kresoxim-methyl. © 1998 Society of Chemical Industry