防除刺萼龙葵的除草剂初步筛选

[目的]刺萼龙葵是外来有毒有害杂草,筛选高效防控药剂对控制其危害蔓延具有重要意义.[方法]采用室内生测法研究了10种茎叶处理除草剂对刺萼龙葵的防效及对植株生物量的影响.[结果]结果表明:百草枯和草甘膦对刺萼龙葵的防效最佳,施药后第5天百草枯的效果达100%,而草甘膦药后15 d可达到相同的防效.氯氟吡氧乙酸、草铵膦和2,4-滴丁酯药后30d对刺萼龙葵也具有较好的防效(≥85%),对植株生物量的抑制效果均在90%以上.[结论]百草枯、草甘膦、草铵膦、氯氟吡氧乙酸和2,4-滴丁酯可作为应急防控刺萼龙葵的候选除草剂.     

15种除草剂防除打碗花、葎草效果评价

在春季采用茎叶处理的施药方式,对比分析了15种防除阔叶杂草的除草剂田间使用防除打碗花、葎草幼苗的效果.药后30 d调查结果表明:不同除草剂对打碗花、葎草防效差异很大.15种除草剂中,防除打碗花效果较好的有20%氯氟吡氧乙酸EC、10%嘧草硫醚AS、72%2,4-滴丁酯EC、56%2甲4氯SP、88%2,4-滴异辛酯EC,试验剂量下对打碗花鲜重防效在85%以上.防除葎草效果较好的有40%嗪草酮WP、75%苯磺降WG、88%2,4-滴异辛酯EC、72%2,4-滴丁酯EC、10%嘧草硫醚AS、10%苄嘧磺隆WP,试验剂量下对葎草鲜重防效在85%以上.80%溴苯腈SP、25%辛酰溴笨腈EC、5%嗪草酸甲酯EC、40%唑酮草酯WG对二者有触杀性防效,但最终防效较低或无防效.     

2,4-滴异辛酯与2,4-滴丁酯室内除草生物活性对比

采用温室盆栽生物测定法, 对比测定了2,4-滴异辛酯和2, 4-滴丁酯茎叶处理对播娘蒿、荠菜、苘麻、反枝苋和土壤处理对茼麻、反枝苋的生物活性.结果表明,2,4-滴异辛酯施药后杂草的受害症状、除草效果均与2,4-滴丁酯相似,且二者茎叶处理活性均明显高于土壤处理活性.2,4-滴异辛酯和2,4-滴丁酯都表现出茎叶处理对反枝苋活性最高,EC50值分别为16.74和11.86 g a.i./hm2;其次为苘麻,EC50值分别为30.23和30.51 g a.i./hm2;对播娘蒿、荠菜的EC50值为89.18～128.56 g a.i./hm2.二者土壤处理对反枝苋、苘麻的EC50值较低,2,4-滴异辛酯处理分别为139.04和136.10 g a.i./hm2,2,4-滴丁酯处理分别为189.91和201.23 g a.i./hm2.     

一种拌种剂对玉米苗期除草剂药害的作用

[目的]对抗多乐(BIO-FORGE,抗氧化剂)保护玉米苗期除草剂药害的效果进行研究。[方法]在室内条件下,对比了每1 kg玉米种子用100 mL 100 mL/L的抗多乐拌种和非拌种后,苗期喷施3、4.5 mL/L 72%2,4-滴丁酯EC,3、4.5 g/L 74.7%草甘膦铵盐SGX,1.5、2.25 mL/L 50%乙草胺EC+1.5 mL/L、2.25 mL/L 38%莠去津SG对玉米苗的药害。[结果]抗多乐可减轻玉米因2,4-滴丁酯和乙草胺+莠去津混合使用造成的药害。虽然不能改变草甘膦造成植株死亡的现实,但在某种程度上能延缓草甘膦对玉米苗造成的药害。[结论]抗多乐拌种对玉米苗期除草剂2,4-滴和乙草胺+莠去津所造成的药害具有保护作用。     

30% 2,4-滴丁酯·辛酰溴苯腈·烟嘧磺隆OD防除玉米田杂草的效果

[目的]通过田间药效试验明确30%2,4-滴丁酯·辛酰溴苯腈·烟嘧磺隆OD对玉米田杂草的防治效果、最佳使用剂量及对玉米的安全性。[结果]30%2,4-滴丁酯·辛酰溴苯腈·烟嘧磺隆OD可有效地防除玉米田杂草。适宜的施药时间为玉米3~5叶期,一年生禾本科杂草2~4叶,阔叶杂草2~5 cm时进行茎叶喷雾处理,适宜的施药剂量为420~630 g a.i./hm2。[结论]30%2,4-滴丁酯·辛酰溴苯腈·烟嘧磺隆OD对玉米田禾本科杂草和阔叶杂草有良好的防效,对玉米安全。     

2,4-滴丁酯除草剂的绿色合成

[目的]2,4-滴丁酯属于苯氧羧酸类除草剂,应用广泛且较少产生耐药性,研发2,4-滴丁酯的绿色合成具有重要意义。[方法]2,4-二氯苯氧乙酸与硼酸三丁酯在无溶剂、无催化剂条件下反应,经减压蒸馏分离得到2,4-滴丁酯。[结果]确定了合成2,4-滴丁酯的最佳反应条件:反应温度140℃,硼酸三丁酯与2,4-二氯苯氧乙酸的摩尔比为2∶1,反应时间4 h,在此条件下酯化率达93.7%。[结论]无溶剂无催化剂条件下合成2,4-滴丁酯,绿色环保,收率高,分离方便,具有工业化应用前景。     

2,4-滴丁酯再评价背景及生物降解的研究进展

2,4-滴丁酯属于苯氧乙酸类除草剂,其对动物的慢性毒性表现为运动组织受损、生理生化功能下降、内分泌系统紊乱和存活率低等。由于2,4-滴丁酯的挥发性、飘移性而易出现作物药害事故。因2,4-滴丁酯的药害问题、对水生生物的毒性以及对人类存在内分泌干扰风险,导致其在我国已被禁用。总结了2,4-滴丁酯的理化性质、国内外的登记情况、生态毒理、健康毒理、暴露评估及生物降解等现状,期望对苯氧乙酸类除草剂和其他高挥发性农药的科学管理提供借鉴。     

杨树幼林化学除草技术

草害是林木生长的大敌。我们于1980年开始在杨树幼林地内,进行了化学除草研究。采用茎叶、土壤处理剂,在不同土壤条件,对药剂配方、施药技术和影响药效的因素等进行了试验,并取得了一定成效。一、试验内容和方法 1、2年生杨树幼林地,采用土壤处理,供试除草剂:氟乐灵、敌草隆、阿特拉津、2,4-滴丁酯、除草醚等。3年生以上经过修枝定干的杨树幼林地,采用处理杂草茎叶,供试除草剂为草甘膦和百草枯。整个试验过程大体分三个阶段。第一阶     

巴西寻求禁止草甘膦、2,4-滴等高风险活性成分的使用

<正>巴西检察官寻求暂停使用孟山都Roundup除草剂中的活性成分草甘膦。最近的一项研究表明草甘膦可能导致一种致命的肾脏疾病,这种疾病已经对全球的贫困农村地区产生影响。据报道,除了草甘膦以外,巴西总检察长办公室还要求禁止以下8种活性成分:2,4-滴、甲基对硫磷、乳铁蛋白、甲拌磷、克百威、阿维菌素、福美双、百草枯。巴西检察长"敦促国家卫生监督机构(ANVISA)重新评估涉嫌对人类健康和环境造成损害的八种活性成分的毒性"。根据检察官网站表示,"有关机构质疑包含2,4-滴除草剂在内的阔叶杂草防除农药登记的情况。"     

除草剂药害新进展与解决方法

近年来除草剂2,4-滴类、烟嘧磺隆对当茬作物药害.二氯喹啉酸、烟嘧磺隆残留药害,2,4-滴丁酯、异哑草松等飘移药害比较突出,常与除草剂药害症状混淆的肥害、人工合成的植物生长调节剂药害,其他如杀菌剂、杀虫剂、栽培措施等应与除草剂加以区别,并应引起重视.解决方法是改进使用技术,限制长残留除草剂使用范围和用量,选用功能性植物营养剂缓解药害.     

共存物质对O3/H2O2工艺降解2,4-D的影响(Ⅰ)2,4-D降解动力学

采用少量无机盐、有机物添加至去离子水配制的2,4-D溶液及自来水、地表水配制2,4-D溶液的方法,模拟实际复杂水质对O3/H2O2工艺降解2,4-D的影响.结果表明不同共存物质对2,4-D降解动力学产生不同的影响,磷酸钠、碳酸钠、硅酸钠、碳酸氢钠、甲酸、硝酸钠、地表水、自来水促进2,4-D降解,氯化钠、叔丁醇、正丙醇、...     

The Effects Of Humic Substances On Pinus Callus Are Reversed By 2,4-Dichlorophenoxyacetic Acid

The reversal of humic matter-induced inhibition of callus growth and metabolism by 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in Pinus laricio. Two forest humic fractions (relative molecular mass (M_r) > 3500), derived from soil under Fagus sylvatica (Fs) and Abies alba (Aa) plantation, were used. Pinus laricio callus was grown for a subculture period (4 weeks) on Basal Murashige and Skoog (MS) medium plus forest humic matters (Fs or Aa), at a concentration of 1 mg C/l, and then was transferred, for an additional four weeks, to a MS medium culture without humic matter, but with different hormones: indole-3-acetic acid (IAA, 2 mg/1) or 2,4-dichlorophenoxyacetic acid (2,4-D, 0.5 mg/1) and/or 6-benzylaminopurine (BAP, 0.25 mg/1). Growth of calluse, glucose, fructose, and sucrose contents, and activities of soluble and bound invertases, glucokinase, phosphoglucose isomerase, aldolase, and pyruvate kinase were monitored. The results show a negative effect of humic fractions on callus growth, due to decreased utilization of glucose and fructose, and decreased activities of glycolytic enzymes. The effects are reversible. Substitution of humic fractions with 2,4-D+BAP or 2,4-D is followed by an increase of glycolytic enzyme activities and, consequently, by the utilization of glucose and fructose that induces a restart of growth. In contrast, the inhibitory effects of humic fractions persist when they are substituted with BAP alone, indicating that only the auxin 2,4-D is capable of reversing the negative effects. A possible competitive action on the auxin-binding site between 2,4-D and the chemical structures in the forest humic fractions is suggested.     

水溶性煤基酸对除草剂生物活性的影响

利用室内生物测定的方法研究了三种不同来源的水溶性煤基酸对六种除草剂 ( 2 ,4- D丁酯、草甘膦、巨星、禾大壮、乙草胺和百草枯 )生物活性的影响 .结果表明 :水溶性煤基酸对2 ,4- D丁酯、草甘膦和巨星的生物活性有明显的增效作用 ;加快了禾大壮的作用速度 ;对乙草胺的生物活性影响较小 ;却使百草枯失去了活性 .三种不同来源的水溶性煤基酸对除草剂生物活性的影响程度不同 ,经化学降解制备的水溶性煤基酸略高于从风化煤中直接提取的水溶性煤基酸 .通过水溶性煤基酸对溶液表面活性以及对除草剂渗透性的影响 ,初步探讨了水溶性煤基酸影响除草剂生物活性的机理     

2,4-滴类药剂防除麦田阔叶杂草的初步研究

采用室内盆栽喷雾法和田间茎叶喷雾处理法,研究了2,4-滴类除草剂防除麦田杂草的应用技术。室内活性试验结果表明,2,4-滴类药剂对麦田杂草的除草活性由高到低依次顺序为:460g/L 2,4-滴.麦草畏水剂>304 g/L 2,4-滴.毒莠定水剂>720 g/L 2,4-滴二甲胺盐水剂>2,4-滴酸原药>50%2,4-滴异辛酯乳油。田间试验结果表明,同一药剂随着剂量的增加,除草效果显著提高,持效期可达45 d以上;2,4-滴类与麦草畏或毒莠定复配后不仅可以提高对阔叶杂草的防效,而且也可以降低单剂的使用量,扩大杀草谱。     

Adsorption of 2,4-D on Mg/Al–NO3 layered double hydroxides with varying layer charge density

Layered double hydroxides (LDHs) have high surface area and high anion exchange capacity, so they have been proposed to be an effective scavenger for contaminants. In this study, the adsorption of 2,4-dichlorophenoxyacetate (2,4-D) on Mg/Al–NO₃ LDHs with varying layer charge density was investigated with particular attention on the effect of the orientation of the interlayer nitrate. Three Mg/Al LDHs were synthesized with Al³⁺/(Al³⁺ + Mg²⁺) molar ratios of 3.3 (LDH3), 2.6 (LDH4) and 2.1 (LDH5). The results of adsorption experiments showed that LDH5 exhibited an S-type isotherm with a low 2,4-D adsorption capacity due to the low accessibility of 2,4-D to the interlayer space. The accessibility was restricted by the small basal spacing of LDH5 as a result of the parallel orientation of the interlayer nitrate with respect to the hydroxide sheet. Thus, the 2,4-D adsorption occurred mainly on the external surface of the material. On the contrary, LDH3, which has the highest layer charge density among the samples, contains nitrate with an orientation perpendicular to the hydroxide sheet of LDH3. The interlayer nitrate was readily exchanged by 2,4-D. Thus, in addition to the adsorption on the external surface, the replacement of the interlayer nitrate by 2,4-D contributed to a higher adsorbed amount of 2,4-D; the 2,4-D adsorption of LDH3 exhibited an L-type isotherm. For LDH4 that contained interlayer nitrate with both parallel and perpendicular orientations, the adsorption characteristics were between those of LDH3 and LDH5. This work has demonstrated the dependence of 2,4-D adsorption characteristics on the nitrate orientation in LDHs, as a consequence of changing layer charge density.     

16种农药对莲草直胸跳甲成虫的生物活性测定

以叶片残留法,在室内测定了农田常用除草剂和杀虫剂对莲草直胸跳甲成虫的影响。试验结果表明:在常用浓度下,2,4-滴丁酯、草甘膦、丁草胺、氟草烟、灭草松、吡氟乙草灵、二甲戊乐灵、烯禾啶、杀螟丹、杀虫双处理后,对莲草直胸跳甲成虫的校正死亡率均小于50%,说明上述农药在常用浓度下对莲草直胸跳甲成虫影响不大;而百草枯、草酮、乐果、敌敌畏、氯氟氰菊酯、鱼藤酮·氰戊菊酯处理后,对莲草直胸跳甲的校正死亡率均大于50%,说明上述农药在常用浓度下对此影响较大。     

共存物质对O3/H2O2工艺降解2,4-D的影响(Ⅱ)氯和过氧化氢动力学分析

为了模拟实际水体中复杂的水质环境,在去离子水配制的溶液里加入少量无机盐、有机物,以及用自来水、地表水配制2,4-D溶液,采用O3/H2O2工艺处理水溶液中2,4-D污染物,通过跟踪反应液内氯离子和过氧化氢的浓度变化,考察共存物质对脱氯和过氧化氢产生分解的影响.实验结果表明,脱氯量小于2,4-D去除量,2,4-D降解过程...     

Treatment of Water Contaminated with Chlorinated Organic Herbicide 2,4-D by an Ozone/Gamma Process

Radiation-induced degradation of 50 ppm 2,4-dichlorophenoxyacetic acid (2,4-D) was investigated in different ozonation times. Co-60 gamma-source was used as a gamma-source with a dose rate of 0.07 kGy/h. Ozonized samples were irradiated for the 0.2 kGy dose. It is observed that irradiation enhances the degradation of 2,4-D with ozone. The amount of passed ozone from samples is between 0.0695 g/L and 8.33 g/L with a flow rate of ozone at 0.078 L/min (10 g/h), from 10 s to 1200 s with the ozone generator. Aliphatic acids and chloride were determined with ion chromatography. Formaldehyde, dissolved oxygen, pH and total acidity were also measured. Both species and amounts of radiolytic intermediates were determined. 2,4-dichloro phenol (2,4-DCP) is one of the toxic intermediates of 2,4-D observed with GC/MS and it decomposes at further ozonation times. It is observed that combination of ozone/gamma irradiation is more effective for degradation of 2,4-D and its intermediate 2,4-DCP. Chloride ions are observed as completely released with combined processes at lower ozonation times although nearly 98% are released with 20 min' ozonation. Intermediate 2,4-DCP decomposes at earlier ozonation times than 2,4-D.