葡萄中克菌丹残留量的气相色谱测定法

研究了葡萄中克菌丹残留分析方法,即用丙酮∶乙酸乙酯（体积比1∶1）高速匀浆提取;提取物用弗罗里硅净化,用带ECD检测器的气相色谱仪进行测定。克菌丹的最低检出量为0.5×10-12 g,在植株、土壤和籽粒中的最低检出浓度为0.01 mg/kg,平均回收率在94.0%～95.3%之间,相对标准偏差为2.6%～7.3%,符合残留分析要求。     

The fungicides thiram and captan affect the phenotypic characteristics of Rhizobium leguminosarum strain C1 as determined by FAME and Biolog analyses

 We assessed the effects of the fungicides captan and thiram on the survival and phenotypic characteristics of Rhizobium leguminosarum bv. viceae, strain C1. Fungicide was applied to pea seed at rates of 0.25–2 g a.i. kg^–1 seed, and treated seed was inoculated with strain C1. After 24 h, rhizobia were extracted from treated seed and viable numbers determined by plating onto yeast extract mannitol agar. Phenotypic characteristics were assessed using FAME (fatty acid methyl ester) profiles and Biolog substrate utilization patterns. Captan and thiram significantly reduced the numbers of rhizobia recovered from seed and altered the FAME and Biolog profiles of recovered rhizobia. However, only the highest concentrations of captan affected nodulation and plant growth. Contact with some seed-applied fungicides can significantly alter phenotypic characteristics of rhizobia, but these changes might be offset by the presence of host plants. Received: 20 February 1999     

Pre- and post-inoculation activity of a protectant and a systemic fungicide for control of anthracnose fruit rot of strawberry under different wetness durations

A protectant fungicide (Captan, a.i. captan) and a systemic fungicide (Switch, a.i. fludioxonil + cyprodinil) were evaluated as pre- and post-inoculation applications for control of anthracnose fruit rot (AFR), caused by Colletotrichum acutatum, under a short (6 or 8 h) or long (18 or 24 h) wetting period. Evaluations were conducted for two seasons in Maryland and for two seasons in Florida. Both Captan and Switch were very effective for control of AFR when applied prior to inoculation, but control was more effective under the shorter wetting period. Switch was as effective when applied 4, 8, or 24 h post-inoculation as when applied before inoculation, but control was better under the short wetting period. Captan was effective when applied 4 or 8 h after inoculation under the short wetting period, but was ineffective at 24 h post-inoculation. Post-inoculation sprays of Captan were ineffective at any time under the long wetting period. The post-infection activity of Switch allows greater flexibility for managing AFR when fungicide applications are scheduled based on weather-based decision-support systems.     

Emergence of cuphea seeds treated with different fungicides

Cuphea (Cuphea viscosissima Jacq. × C. lanceolata f. silenoides W.T. Aiton, Lythraceae) is an oilseed crop, with medium-chain fatty acids, being developed for the North Central United States for industrial applications in the manufacture of soaps and detergents. Seed germination and seedling emergence of cuphea is often low when compared to the commercial crops. Identification of seed treatments to optimize seedling emergence and stand establishment for cuphea are important for commercial production. The objective of this study was to determine the effect of several fungicide treatments on pure live seed emergence (PLSE) of cuphea. Pure live seed emergence is defined as total seedling emergence adjusted by the germination of the seed planted. Field experiments were conducted at Prosper, ND and Glyndon, MN, in 2005 and 2006. Previous crop rotations were soybean [Glycine max (L.) Merr.]/hard red spring wheat (Triticum aestivum L.), and soybean/hard red spring wheat/sugarbeet (Beta vulgaris var. saccharifera L.) at Prosper and Glyndon, respectively, for both years. The experimental design was a randomized complete block with six treatments and four replicates. Treatments were: no fungicide applied (check treatment), captan, mefenoxam, fludioxonil + mefenoxam, azoxystrobin, and azoxystrobin + mefenoxam. Plant stand was counted and PLSE was calculated 10 to 15 d after seeding at all locations by counting emerged seedlings in the center two-plot-rows and adjusting PLSE for germination. Greenhouse experiments were conducted with soil treatments (pasteurized and non-pasteurized) and the same fungicide seed treatments as the field experiment. Pure live seed emergence, vigor index, and percent of diseased seedlings were recorded. Plant stand and PLSE were significantly greater for the seed treatments that had mefenoxam at the Glyndon, MN, environments, in which the previous crop was sugarbeet. Soil treatment (pasteurization) increased PLSE and vigor index. All fungicide seed treatments improved PLSE and vigor index and reduced damping-off compared to the untreated check. Results suggest that seed treatments including mefenoxam would be beneficial for commercial cuphea production.     

Mycorrhizae, biocides, and biocontrol 3. Effects of three different fungicides on developmental stages of three AM fungi

The effects of biocide use on nontarget organisms, such as arbuscular mycorrhizal (AM) fungi, are of interest to agriculture, since inhibition of beneficial organisms may counteract benefits derived from pest and disease control. Benomyl, pentachloronitrobenzene (PCNB) and captan were tested for their effects on the germination and early hyphal growth of the AM fungiGlomus etunicatum (Becker & Gerd.),Glomus mosseae (Nicol. & Gerd.). Gerd. and Trappe andGigaspora rosea (Nicol & Schenck) in a silty-clay loam soil placed in petri plates. Application of fungicides at 20 mg active ingredient (a.i) kg^–1 soil inhibited spore germination by all three AM-fungal isolates incubated on unsterilized soil for 2 weeks. However, fungicides applied at 10 mg a.i. kg^–1 soil had variable effects on AM-fungal isolates. Fungicide effects on germination and hyphal growth of G.etunicatum were modified by soil pasteurization and CO₂ concentration in petri plates and also by placing spores below the soil surface followed by fungicide drenches. Effects of fungicides on mycorrhiza formation and sporulation of AM fungi, and the resulting host-plant response, were evaluated in the same soil in associated pea (Pisum sativum L.) plants. Fungicides applied at 20 mg a.i. kg^–1 soil did not affect the root length colonized byG. etunicatum, but both benomyl and PCNB reduced sporulation by this fungus. Benomyl and PCNB reduced the root length colonized byG. rosea at 48 and 82 days after transplanting. PCNB also reducedG. mosseae-colonized root length at 48 and 82 days, but benomyl only affected root length colonized byG. mosseae at the earlier time point. Only PCNB reduced sporulation byG. mosseae, consistent with its effect on root length colonized by this fungus. captan reduced the root length colonized by G. rosea at 48 days, but not at 82 days, and reduced colonization byG. mosseae at 82 days, but not at 48 days. Captan did not affect sporulation by any of the fungi.G. rosea spore production was highly variable, but benomyl appeared to reduce sporulation by this fungus. Overall,G. etunicatum was the most tolerant to fungicides in association with pea plants in this soil, andG. rosea the most sensitive. Benomyl and PCNB were overall more toxic to these fungi than captan. Interactions of AM fungi and fungicides were highly variable and biological responses depended on fungus-fungicide combinations and on environmental conditions.     

GC-MS联机技术对克菌丹原药及其主要杂质的定性分析

气相色谱和质谱联机是分离和检测有机物及其杂质和代谢产物,并进行定性定量的一种有效方法。本文采用GC-MS对克菌丹原药主成分及其主要杂质进行定性分析,并确定了2个主要杂质。GC条件为:HP-5毛细管色谱柱(30m×0.25mm×0.25um),氦气1mL/min,进样口温度200℃,柱温从50℃(1min)→200℃(10℃/min,2min)→280℃(20℃/min,2min),进样量1μL。MS条件为,离子源230℃,扫描范围12~350amu。     

克菌丹在苹果园土壤中的代谢研究

GC-M S是对农药及其代谢物进行定性定量分析的重要方法。本研究采用气相色谱-质谱(GC-M S)联用研究了克菌丹在土壤及苹果中的代谢,确证了克菌丹的代谢物为四氢邻苯二甲酰亚胺。克菌丹在土壤中的半衰期为1.6~1.9 d。最低检出浓度为0.006 m g/kg。     

克菌丹原药中微量四氯化碳测定方法的研究

建立了气相色谱法测定克菌丹原药中微量四氯化碳含量的方法,采用DB-624毛细管柱分离,氢火焰离子化检测器检测。在选定的色谱条件下,四氯化碳与克菌丹中杂质能得到有效分离,并能获得较好的检测效果。分析结果表明,四氯化碳的质量浓度在0~9.53μg/m L范围内线性关系良好,其线性相关系数为0.999 4;加标回收率为92.30%~105.8%,变异系数为2.88%,最低检出浓度为0.39μg/m L,最小检出量为0.39ng。