有机硅助剂对草甘膦增效作用研究

进行了不同有机硅助剂对草甘膦防除非耕地杂草的增效试验。结果表明,有机硅Fairland 2625、Fairland 2626和Silwet 625可提高草甘膦防除非耕地杂草的速效性,杂草出现受害症状比未添加有机硅助剂的处理提前2～3 d;三种有机硅助剂对禾本科杂草的株防效与鲜重防效以及对阔叶杂草的株防效无显著影响,但均可显著增加对阔叶杂草的鲜重防效。在以草甘膦防除非耕地杂草时,建议将95%草甘膦铵盐可溶性粒剂与有机硅助剂Fairland 2625、Fairland 2626和Silwet 625按每40 g制剂添加5 ml助剂的比例推广使用。     

农药助剂牛脂胺聚氧乙烯醚的毒性及其分析技术研究进展

牛脂胺聚氧乙烯醚是一类广泛用于草甘膦制剂的农药助剂。大量研究表明,该助剂的毒性大于其活性成分草甘膦,因而引起了国内外研究人员的关注。本文对牛脂胺聚氧乙烯醚的结构、毒性以及其目前在环境中的分布水平和分析方法等内容进行了综述,旨在为牛脂胺聚氧乙烯醚在我国农药助剂领域的进一步研究、规范使用和管控提供科学依据。     

增效草甘膦田间除草试验简报

草甘膦茎叶喷雾,除草效果的优劣,很大程度取决于它渗入植物体内量的多少。由于植物叶片表面为角质层,外层主要是腊质,国产草甘膦现在多为水剂,喷施于叶面上,药液的湿润性、展着性和渗透性能都较差,影响了该药被植物吸收、传导,药效难以充分发挥。为了提高该药的生物效应,1987年化工部沈阳化工研究院对草甘膦进行了新制剂配方研究。“增效草甘膦”即是草甘膦与特种助剂复配的新制剂。由于新制剂改善了草甘膦水剂的物     

复合型助剂对不同除草剂的增效作用

本文利用田间试验及仪器分析的方法系统研究了不同类型助剂对除草剂的增效作用。结果表明,供试的几种助剂对草甘膦都具有明显的增效作用,其增效顺序为:复合型助剂>甲酯化植物油>有机硅助剂>非离子表面活性剂>葡萄糖助剂>氮盐类助剂。复合型助剂能够明显降低草甘膦药液的表面张力及干燥时间,降低幅度可达30%以上,并且明显增加药液的扩展直径、黏度及其在叶片上的最大持留量,增加率均在40%以上。因此表明复合型助剂对草甘膦具有明显的增效作用。并且,复合型助剂对烯草酮乳油及莠去津悬浮剂具有明显的增效作用(株防效分别增加至少9.34%、10.41%),并且随着助剂添加量越高,增效越强。     

几种有机硅助剂对草甘膦在单子叶植物体内吸收、转移和分布的影响

采用14C-草甘膦同位素标记法研究了4种有机硅助剂Silwet L-77、Silwet 800 、Freeway 和Boost 在体积分数0.1%用量下对草甘膦在黑麦草( Lolium perenne L. cv. Grasslands Greenstone)体内吸收、转移和分布的影响。结果表明:与单用草甘膦相比，4 种助剂的加入显著地降低了草甘膦在黑麦草体内的吸收和转移量，助剂之间无显著性差异。 处理后24和72 h测定，草甘膦主要分布在幼嫩组织中，其次是根部，在老叶片中的转移量最 少。无论转移量高低，草甘膦在植物体内的分布总是表现为地上部的比例高于地下部。有机 硅助剂对草甘膦在各组织中的分布比例没有影响。     

草甘膦制剂的质量状况及监管对策

近年来,在全国农药监督抽查中发现,草甘膦农药存在以铵盐或钠盐冒充异丙胺盐、甲醛超标等质量问题。本文梳理了草甘膦制剂产品市场监管及实际调研存在的问题,并对产生问题的原因进行了分析,提出了加强草甘膦制剂监管的建议。     

有机硅喷雾助剂对草甘膦在空心莲子草上的沉积和生物活性的影响

研究了有机硅喷雾助剂(OSA)对草甘膦在空心莲子草Alternanthera philoxeroides上的沉 积与生物活性的影响。当采用较大喷雾雾滴,施药液量高于632.5 L/hm2时,添加OSA(0.35 g/L) 后,草甘膦药液在空心莲子草上的沉积量显著下降。最大稳定持留量(MRG)由未添加OSA的0.61~0.63 μ L/cm2下降到0.50~0.54 μ L/cm2。分别以33.7和67.4 μ g/株剂量的草甘膦点叶处理空心莲子草,发现添加OSA的处理对再生植株茎叶生长的抑制率分别比对照提高了8.89%和14.83%。草甘膦(有效成分199.3 g/hm2)施药后1 h进行人工模拟降雨处理,添加OSA后药剂对空心莲子草的生物活性比无OSA对照处理提高了20.5%。研究结果表明,添加有机硅喷雾助剂促进了草甘膦在空心莲子草中的向下传导性能,提高了草甘膦水剂在空心莲子草叶片的耐雨水冲刷性能,但会降低草甘膦药液在空心莲子草上的最大稳定持留量。     

天然植物源助剂SD、SDP的特性及与除草剂应用效果

天然植物源助剂SD、SDP具有良好的润湿性、渗透性和粘着性 ,此助剂与除草剂、杀虫剂混用 ,能提高药效 ,减少药液流失 ,具有抗雨水冲刷的功能。本文介绍了其作用特点 ,基础应用研究的结果 ,以及SD、SDP与胺苯磺隆、草甘膦等除草剂使用技术和开发前景     

农药制剂中助剂安全性探讨及管理建议

本文对农药助剂的发展历史和种类进行了介绍,举例说明了制剂中的有机溶剂、表面活性剂等常用助剂对人畜的危害情况,并对国外在助剂的种类和使用量方面的相应限定和管理措施进行了简述。并提出正确评价农药助剂的安全性,规范其应用,以便更好的保护环境、保障农产品安全。     

第三届中国草甘膦产业发展高峰论坛在杭州召开

5月11—13日,由中国化工报社主办的2010年（第三届）中国草甘膦产业发展高峰论坛在杭州隆重召开,来自全国草甘膦和助剂生产企业、进出口贸易企业、科研院所、推广应用单位以及农化媒体的代表100多人出席会议。会上,有关专家就草甘膦产业的发展作了精彩报告。     

Comparison of commercial glyphosate formulations for control of prickly sida, purple nutsedge, morningglory and sicklepod

The efficacy of the commercial glyphosate [( N -phosphonomethyl) glycine] formulations Roundup Ultra, Touchdown and Engame were compared for the control of prickly sida ( Sida spinosa L.), morningglory ( Ipomeae hederacea var. integriuscula Gray), sicklepod ( Senna obtusifolia L.) and purple nutsedge ( Cyperus rotundus L.). Engame is a new formulation of glyphosate that contains glyphosate acid and 1-aminomethanamide dihydrogen tetraoxosulfate (AMADS), a proprietary mixture of sulfuric acid and urea, other than glyphosate salt and surfactants. Injury by Engame differed from Roundup Ultra and Touchdown in that necrotic lesions formed on leaves several hours after treatment. Leaves of very susceptible species, such as prickly sida, were rapidly, although incompletely, desiccated and then became chlorotic and died in a manner typical of other glyphosate formulations. Engame was 2–3 times more active to growth inhibition than either the Roundup Ultra or Touchdown formulations, based on GR₅₀ comparisons expressed on an acid equivalent basis. The GR₅₀ estimates did not change over the 3 week evaluation period for prickly sida and purple nutsedge, and after 2 weeks after treatment for morningglory. The GR₅₀ estimates for sicklepod decreased over the 3 week evaluation period indicating a slower response to glyphosate. The application of AMADS alone caused minute necrotic lesions on sicklepod and purple nutsedge, and lesions up to 3 mm in diameter on prickly sida and morningglory. Further injury from AMADS was not noted and plants resumed growth without apparent delay. At glyphosate rates above 1120 g ha⁻¹, greater than 80% control was achieved at 7 days after treatment. These results demonstrate that glyphosate efficacy can be further enhanced by formulations that apparently improve uptake and translocation.     

A scanning electron microscope study of glyphosate deposits in relation to foliar uptake

The effects of several formulations on foliar uptake of glyphosate, and on the morphology of glyphosate deposits on leaves, were examined in Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.). [¹⁴C]glyphosate, in the form of the free acid or the isopropylamine salt (IPAS), was applied to foliage alone or with various adjuvants. Uptake of all glyphosate IPAS formulations was greater than that of the corresponding acid formulation. Addition of ‘Tween 20’ enhanced the uptake of glyphosate IPAS compared to glyphosate alone, but had no effect on the uptake of glyphosate acid. Ammonium sulfate and the ‘Roundup’ formulation blank increased the uptake of glyphosate acid and IPAS to 2-3 times that of herbicide alone. Surface deposits, as observed by scanning electron microscopy, varied with the formulation of the herbicide, although there were no differences between the acid and IPAS formulations. Glyphosate alone initially formed a deposit with both crystalline and smooth, amorphous areas. Later in the treatment period (48 and 72 h after application), the deposit was almost entirely crystalline. The addition of ‘Tween 20’ or of formulation blank resulted in the formation of a more amorphous, non-crystalline deposit. Herbicide solutions containing ammonium sulfate dried to form a highly crystalline deposit. However, crystals similar to those of glyphosate alone were not visible in these deposits. The ability of these adjuvants to prevent or delay crystal formation may play a role in their enhancement of herbicide uptake.     

Joint action of amino acid biosynthesis-inhibiting herbicides

The joint action of binary mixtures of the amino acid biosynthesis‐inhibiting herbicides glyphosate, glufosinate‐ammonium, metsulfuron‐methyl and imazapyr was assessed in pot experiments applying the Additive Dose Model (ADM). Plants of Sinapis arvensis or S. alba were sprayed with seven doses of the herbicides alone and binary fixed‐ratio mixtures of the four herbicides. In total, 73 binary mixtures were studied in six separate experiments. Mixtures of glyphosate and glufosinate‐ammonium were less phytotoxic than predicted by ADM whether commercial formulations or technical grade products were applied. In contrast, mixtures of glyphosate and metsulfuron‐methyl, glyphosate and imazapyr, glufosinate‐ammonium and metsulfuron‐methyl, glufosinate‐ammonium and imazapyr, and metsulfuron‐methyl and imazapyr either followed ADM or were synergistic. Synergism was observed most frequently for mixtures of glyphosate or glufosinate‐ammonium with metsulfuron‐methyl. Synergism was also more pronounced for commercial formulations of glyphosate and glufosinate‐ammonium than for the corresponding technical grade formulations, implying that synergism was caused by the presence of the formulation constituents of the commercial glyphosate and glufosinate‐ammonium formulations in the spray solution.     

Some physicochemical factors influencing foliar uptake enhancement of glyphosatemono(isopropylammonium) by polyoxyethylene surfactants

Structure-concentration–foliar uptake enhancement relationships between commercial polyoxyethylene primary aliphatic alcohol (A), nonylphenol (NP), primary aliphatic amine (AM) surfactants and the herbicide glyphosatemono(isopropylammonium) were studied in experiments with wheat (Triticum aestivum L.) and field bean (Vicia faba L.) plants growing under controlled-environment conditions. Candidate surfactants had mean molar ethylene oxide (EO) contents ranging from 5 to 20 and were added at concentrations varying from 0·2 to 10 g litre^?-1 to [¹⁴C]glyphosate formulations in acetone–water. Rates and total amounts of herbicide uptake from c. 0·2–μl droplet applications of formulations to leaves were influenced by surfactant EO content, surfactant hydrophobe composition, surfactant concentration, glyphosate concentration and plant species, in a complex manner. Surfactant effects were most pronounced at 0·5 g acid equivalent (a.e.) glyphosate litre^?-1 where, for both target species, surfactants of high EO content (15–20) were most effective at enhancing herbicide uptake: surfactants of lower EO content (5–10) frequently reduced, or failed to improve, glyphosate absorption. Whereas, at optimal EO content, AM surfactants caused greatest uptake enhancement on wheat, A surfactants gave the best overall performance on field bean; NP surfactants were generally the least efficient class of adjuvants on both species. Threshold concentrations of surfactants needed to increase glyphosate uptake were much higher in field bean than wheat (c. 2 g litre^?-1 and < 1 g litre^?-1, respectively); less herbicide was taken up by both species at high AM surfactant concentrations. At 5 and 10 g a.e. glyphosate litre^?-1, there were substantial increases in herbicide absorption and surfactant addition could cause effects on uptake that were different from those observed at lower herbicide doses. In particular, the influence of EO content on glyphosate uptake was now much less marked in both species, especially with AM surfactants. The fundamental importance of glyphosate concentration for its uptake was further emphasised by experiments using formulations with constant a.i./surfactant weight ratios. Any increased foliar penetration resulting from inclusion of surfactants in 0·5 g litre^?-1 [¹⁴C]glyphosate formulations gave concomitant increases in the amounts of radiolabel that were translocated away from the site of application. At these low herbicide doses, translocation of absorbed [¹⁴C]glyphosate in wheat was c. twice that in field bean; surfactant addition to the formulation did not increase the proportion transported in wheat but substantially enhanced it in field bean.     

A critique of studies evaluating glyphosate effects on diseases associated with Fusarium spp.

With the large-scale adoption of glyphosate-resistant crops in North America, there are concerns that non-target microbial populations might be affected by increased frequency of glyphosate use. Stimulation of fungal species associated with crop diseases, including Fusarium spp., has been observed in laboratory and glasshouse experiments. Although field surveys in Saskatchewan detected positive associations between the incidence of Fusarium head blight and application of glyphosate formulations, few field experiments have been successful at demonstrating a stimulatory effect of glyphosate on crop diseases, including diseases associated with Fusarium spp. Taken at face value, there is little evidence from experimental field trials to support a causative link between glyphosate and crop diseases associated with Fusarium spp. However, we are concerned that the experimental field trials investigating links between glyphosate and Fusarium spp. are not representative of interactions that occur under actual farming conditions. In addition, inadequate consideration may have been given to microbial ecology during the design and maintenance of these experimental field trials. At this time, there is insufficient evidence to prove or disprove a link between glyphosate and crop diseases associated with Fusarium spp. and this area should receive high research priority, given the rapid and widespread increase in glyphosate use.     

不同生育期转基因抗草甘膦抗虫棉花对草甘膦的耐受性

为明确转基因抗草甘膦抗虫棉田草甘膦的使用适期,于棉花子叶期、3~4片真叶期和花铃期喷施不同浓度的草甘膦,比较药害发生情况、棉花产量和纤维品质。棉花子叶期、3~4片真叶期和花铃期喷施1 640~9 840 g/hm²(有效成分,下同)草甘膦后,施药初期棉花均表现出一定的药害症状,药后4~8 d药害株率和药害指数达最大值,药后12 d药害症状逐渐减轻或消失。棉花子叶期和3~4片真叶期喷施草甘膦,对棉花产量无显著影响,但棉花花铃期喷施2 460~9 840 g/hm²草甘膦后,棉花产量显著降低,降幅达35.0%~63.3%。3个时期喷施草甘膦均不影响棉花的纤维品质。研究表明,转基因抗草甘膦抗虫棉田草甘膦的使用适期为棉花苗期。     

Applying the double knock technique to control Conyza bonariensis

Sequential applications of glyphosate followed by another postemergent herbicide, known as the "double knock" technique, were trialled for their effectiveness in controlling Conyza bonariensis . Combinations of glyphosate with and without 2,4-D followed by paraquat plus diquat, paraquat, or 2,4-D were tested at a range of follow-up application times in two field and two pot experiments. The results showed that paraquat plus diquat or paraquat following glyphosate or glyphosate plus 2,4-D provided highly effective weed control compared to glyphosate alone. The optimum timing for follow-up applications of paraquat or paraquat plus diquat was between 5 and 7 days after the initial glyphosate application. Combined applications of glyphosate and 2,4-D, compared to split applications, were not significantly different. However, following glyphosate application with 2,4-D >1 day later considerably reduced the level of control. This study showed that the double knock technique is highly effective in controlling C. bonariensis and is rapidly becoming an important tool in the management of this problem weed.     

Surfactant and salt affect glyphosate retention and absorption

The influence of nonylphenoxy surfactants and glyphosate salt formulation on spray retention, phytotoxicity and [¹⁴C]glyphosate uptake was investigated in wheat (Triticum aestivum L). and Kochia scoparia L. The amount of spray retained, and uptake of [¹⁴C]glyphosate increased with increasing hydrophilic-lipophilic balance (HLB) value of surfactants. The volume of spray delivered to the plant treatment area and retained by wheat and K. scoparia plants increased with increasing surfactant HLB values, but this only partly accounted for the higher spray retention. Spray retention by leaves of plants was not affected by calcium chloride, either alone or with ammonium sulphate in the glyphosate spray solution. [¹⁴C]Glyphosate absorption by wheat and K. scoparia was reduced by calcium chloride alone, but not in mixtures with ammonium sulphate, regardless of surfactant. Phytotoxicity and uptake of glyphosate salt formulations for wheat was: isopropylamine > ammonium > sodium > calcium; these results indicate that the surfactant selected is important to maintain glyphosate efficacy and that sodium and calcium cations antagonize glyphosate by forming salts that are absorbed less than commercial isopropylamine formulations.     

Comparison of efficacy, absorption and translocation of three glyphosate formulations on velvetleaf (Abutilon theophrasti)

Growth analysis, absorption and translocation studies were conducted to compare a 1-aminomethanamide dihydrogen tetraoxosulfate (GLY-A) formulation of glyphosate with two isopropylamine (GLY-IPA-1, GLY-IPA-2) formulations of glyphosate on velvetleaf. The two isopropylamine formulations differed by the presence of a surfactant in the formulation, GLY-IPA-1 containing surfactant whereas GLY-IPA-2 did not. Four- to six-leaf velvetleaf was treated with GLY-A and GLY-IPA-1 and GLY-IPA-2 (0, 50, 67, 89, 119, 158, 280, 420, 560 and 840 g AE ha(-1)) with and without ammonium sulfate (AMS; 20 g L(-1)). GLY-A and GLY-IPA-2 included a non-ionic surfactant (2.5 mL L(-1)) in the spray solution at all herbicide concentrations. No additional surfactant was added to GLY-IPA-1. The IC50 value for GLY-A was 88 g AE ha(-1) compared with 346 and 376 g AE ha(-1) for GLY-IPA-1 and GLY-IPA-2 respectively in the absence of AMS. When AMS (20 g L(-1)) was added to the spray solution, the estimated IC50 values were 143, 76 and 60 g AE ha(-1) for GLY-IPA-1, GLY-IPA-2 and GLY-A respectively. Absorption of 14C-glyphosate into the third leaf of five- to six-leaf velvetleaf was three- to sixfold greater 72 h after treatment (HAT) when applied as GLY-A compared with GLY-IPA-1 and GLY-IPA-2 respectively in the absence of AMS. AMS (20 g L(-1)) increased absorption of 14C-glyphosate in all glyphosate formulations two- to threefold, but differences among the formulations remained. Approximately three- and sixfold more 14C-glyphosate applied as GLY-A had translocated out of the treated leaf compared with GLY-IPA-1 and GLY-IPA-2 respectively by 72 HAT. Adding AMS (20 g L(-1)) increased translocation of 14C-glyphosate out of the treated leaf approximately 2.5-fold for all three formulations. The increased efficacy of GLY-A versus GLY-IPA-1 and GLY-IPA-2 on velvetleaf is due to the greater rate of absorption and subsequent translocation of glyphosate out of the treated leaf. AMS increased the efficacy of all three formulations by increasing absorption and translocation of glyphosate in the plant.