Sensitivity of Adzuki Bean (<i>Vigna angularis</i>) to Acifluorfen, Fomesafen, Bentazon, Imazethapyr and Halosulfuron-Methyl Applied Postemergence

New herbicide options are needed for postemergence (POST) broadleaf weed control in adzuki bean. A field study, of five experiments, was conducted over a three-year period (2014, 2015, 2016) in Ontario to evaluate the tolerance of adzuki bean to the POST application of acifluorfen (600 and 1200 g&middot;ai&middot;ha-1), fomesafen (240 and 480 g&middot;ai&middot;ha-1), bentazon (1080 and 2160 g&middot;ai&middot;ha-1), imazethapyr (100 and 200 g&middot;ai&middot;ha-1) and halosulfuron-methyl (75 and 150 g&middot;ai&middot;ha-1). Acifluorfen and fomesafen applied POST caused as much as 12% visible injury at the 1X rate and 20% visible injury at the 2X rate but had no adverse effect on adzuki bean population, shoot dry weight, height, maturity or yield. Bentazon caused as much as 23% visible injury at 1080 g&middot;ai&middot;ha-1 and 28% visible injury at 2160 g&middot;ai&middot;ha-1 but caused no adverse effect on adzuki bean population, shoot dry weight, height, maturity or yield at either rate, except at 2160 g&middot;ai&middot;ha-1 which reduced shoot dry weight 20% and height 12%. Imazethapyr caused as much as 22% visible injury at 100 g&middot;ai&middot;ha-1 and 34% visible injury at 200 g&middot;ai&middot;ha-1 but caused no adverse effect on adzuki bean population, shoot dry weight, height, maturity or yield at either rate except at 200 g&middot;ai&middot;ha-1 which delayed maturity slightly. Halosulfuron-methyl caused as much as 65% visible injury and reduced shoot dry weight, height and yield 64%, 41%, and 28%, respectively. This research concludes that acfluorfen, fomesafen, bentazon, imazethapyr and halosulfuron at the rates evaluated can cause the significant injury in adzuki bean.

Characteristics and Degradation Mechanism of Fomesafen

High performance liquid chromatography(HPLC) was used to determine the degradation efficiency of bacteria 2 strain(B2 S) under different conditions, the optimum cultivation conditions for fomesafen degradation bacterium B2 S were as the followings: temperature 35℃; inoculation quantity 5%; p H 5.0; glucose content 0.5% and fomesafen concentration 10 mg · L-1. Under optimal conditions, B2 S degraded fomesafen within 72 h of fomesafen application, with a degradation rate of nearly 100%. High performance liquid chromatography-mass spectrometry(HPLC-MS) was used to analyze fomesafen degradation into microbial products. A more thorough understanding of microbial fomesafen degradation mechanisms was discussed. The pathway of fomesafen degradation by B2 S was also inferred herein.

Influence of Water Quality, Formulation, Adjuvant, Rainfastness, and Nozzle Type on Efficacy of Fomesafen on Palmer Amaranth (<i>Amaranthus palmeri</i>) Control

Protoporphyrinogen oxidase (PPO) inhibitors are one of the few remaining postemergence herbicide options for controlling Palmer amaranth in soybean growing areas of Mississippi, USA. Most Palmer amaranth populations in Mississippi are resistant to both glyphosate and acetolactate synthase inhibitors. Resistance to PPO inhibiting herbicides in Palmer amaranth has very recently been reported in Arkansas, Tennessee, and isolated pockets of Mississippi. A significant proportion of reports of PPO inhibitor failures in Mississippi are not considered to be resistance-related at this time. Therefore, the objective of this research was to evaluate factors affecting the efficacy of fomesafen on Palmer amaranth including: quality of spray carrier (water), formulations, adjuvant, rainfastness, and nozzle type. All water samples and formulation combinations provided >95% control of Palmer amaranth 3 WAT. Some combinations of water samples and formulations did not result in complete control of the treated plants, with one or two individuals surviving 3 WAT. Formulation 1 provided 99% control compared to 95% from formulation 2. Irrespective of combinations of herbicide, adjuvant and height, control of Palmer amaranth was ≥91%. Formulation 1 provided 94% control compared to 88% from formulation 2. The adjuvant x height interaction was significant, owing to a 10% reduction in control of larger plants (86%) compared to smaller plants (96%) in presence of COC. COC provided better control (93%) than NIS (88%). Simulated rainfall applied ≥60 min after herbicide application did not adversely affect efficacy on Palmer amaranth when formulation 1 was applied in combination with NIS, with control ranging from 94% to 100%. Formulation 1 with COC provided ≥93% control at all rainfall application times, except 30 min after herbicide treatment, which resulted in 79% control. Formulation 2 provided better control with COC (79% to 100%) than NIS (71% to 90%), in general, across the rainfall treatments applied at various times following herbicide application. All nozzle and weed height combinations resulted in 89% or better control of Palmer amaranth. In summary, water quality, formulation, adjuvant, rainfastness, or nozzle type did not affect the activity of fomesafen under optimal application conditions in the greenhouse.

Effects of Methylated Soybean Oil Adjuvant on Fomesafen Efficacy to Weeds

Tank-mix adjuvant has the potential to improve the weed control efficacy of post-emergence herbicides. In order to study the synergistic effect of adjuvant, the effects of different rates of fomesafen alone or applied methylated soybean oil adjuvant（MSO） were sprayed on redroot pigweed, abutilon and black nightshade under greenhouse condition. The results showed that fomesafen had different performance on the three weeds, and MSO adjuvant could effectively increase the control. The nightshade control was lower than other two weeds with all the fomesafen doses from 131.25 to 506.25 ga.i. · hm-2 with or without adjuvant. The control of abutilon was between the black nightshade and the redroot pigweed, and had better control at 375 ga.i. · hm-2 with adjuvant or 506.25 ga.i. · hm-2 alone or with adjuvant respectively. The results indicated that mixing adjuvant with fomesafen improved the control on weeds, especially at the low rate. Black nightshade was more difficult to control. The redroot pigweed had the most susceptibility to fomesafen alone or with adjuvant.

碳量子点修饰g-C_(3)N_(4)缓解二苯醚类除草剂污染

为加速二苯醚类除草剂在可见光环境的降解,以玉米芯制碳量子点修饰石墨相氮化碳,合成一种非金属型光催化剂.考察在该催化剂作用下,氟磺胺草醚、三氟羧草醚和乙氧氟草醚等的光解行为及光解前后毒性.结果表明,氟磺胺草醚在可见光照射下的光解速率最大、其次为乙氧氟草醚,光照3 h的降解率即达99%和91%,而三氟羧草醚的光解速率最低、须光照至8 h才能达到90%的降解率.由高斯软件计算NPA(Natural Population Analysis)电荷分布得福井函数和双描述符,预测反应位点并结合液质联用分析降解产物,推测除草剂的降解过程应包括裂解、水解、脱卤、还原和羟基化等,证明了空穴和羟基自由基在其中的作用.观察玉米种子的生长实验,发现氟磺胺草醚的毒性略高于乙氧氟草醚,但二者经光照处理后毒性均显著下降,三氟羧草醚及其光解产物显示为低毒性.

Effects of aging process on adsorption–desorption and bioavailability of fomesafen in an agricultural soil amended with rice hull biochar

Biochar has been introduced as an acceptable soil amendment due to its environmental benefits such as sequestering soil contaminants. However, the aging process in biochar amended soil probably decreases the adsorption capacity of biochar through changing its physico-chemical properties. Adsorption, leaching and bioavailability of fomesafen to corn in a Chinese soil amended by rice hull biochar after 0, 30, 90 and 180 days were investigated. Results showed that the addition of 0.5%-2% fresh biochar significantly increases the adsorption of fomesafen 4-26 times compare to unamended soil due to higher SSA of biochar. Biochar amendment also decreases fomesafen concentration in soil pore water by 5%-23% resulting lower risk of the herbicide for cultivated plants. However, the aging process decreased the adsorption capacity ofbiochar since the adsorption coefficient values which was 1.9-12.4 in 0.5%-2% fresh biochar amended soil, declined to 1.36-4.16, 1.13-2.78 and 0.95-2.31 in 1, 3 and 6-month aged treatments, respectively. Consequently, higher desorption, leaching and bioavailable fraction of fomesafen belonged to 6-month aged treatment. Nevertheless, rice hull biochar was effective for sequestering fomesafen as the adsorption capacity of biochar amended soil after 6 months of aging was still 2.5-5 times hi^her compared to that of unamended soil.

39%氟·松·烯草酮乳油在东北地区春大豆田的应用效果

为明确39%氟·松·烯草酮乳油对东北地区春大豆田一年生杂草的防效及最佳用量,采用随机区组试验设计方法进行田间药效试验。结果表明,39%氟·松·烯草酮乳油在有效成分用量为611.0,666.5,722.0和1333.0 g·hm^(-2)的条件下,施药后30 d,对大豆田一年生杂草总的株数防效分别为93.9%、97.0%、98.7%和99.6%,总草鲜重防效分别为96.0%、98.3%、99.1%和99.8%,与空白对照相比,大豆增产率分别为196.2%、203.8%、204.9%和198.1%。由此可知,39%氟·松·烯草酮乳油在本试验剂量下,于大豆1~2片复叶、杂草2~4叶期进行茎叶喷雾处理,对大豆安全,除草效果好,有增产作用,可作为东北地区春大豆田除草剂使用。适宜的施药剂量为105.0~123.0 mL·(666.7 m^(2))^(-1),即有效成分用量为611.0~722.0 g·hm^(-2)。

大豆茎叶除草应用缓解剂增产效果分析

在筛选适宜的茎叶除草缓解剂处理,以期解决茎叶除草造成大豆叶片损伤继而影响产量问题。以大豆品种“克豆52”为试材,利用松·喹·氟磺胺乳油茎叶除草处理。3种缓解剂GAP、GAL、GAC分别设置3个浓度2个施用时期共18个处理,CKW茎叶除草次日喷清水,CKA仅进行茎叶除草。通过调查、统计、分析大豆叶片药害指数、株高、节数、有效荚数、百粒重,结合经济效益和对杂草影响决选最优处理。结果表明,AC1处理便于农户掌握,产量最高,增产18.48%,综合收益较高,对除草效果影响较小,值得在生产上推广。

38%灭·喹·氟磺胺微乳剂的研制

通过对溶剂、乳化剂及成盐物的筛选和配伍,确定了38%灭·喹·氟磺胺微乳剂最佳配方:灭草松25%,精喹禾灵3%,氟磺胺草醚10%,二甲苯10%,氢氧化钠5.3%,烷基糖苷6%,脂肪醇聚氧乙烯醚10%,乙二醇5%,消泡剂0.1%,自来水补足100%。该剂型配方具有良好的热储稳定性、低温冷冻稳定性及较宽的透明温度范围,各项性能指标均符合微乳剂产品的标准要求。

六种有机硅助剂对氟磺胺草醚的增效作用及其增效机理初探

采用温室盆栽法研究了6种不同结构的有机硅助剂对氟磺胺草醚防除阔叶杂草苘麻的增效作用及其增效机制。于苘麻4-5叶期,分别喷施添加有机硅助剂Agrowet 818、Agrowet 820、GY-S903、Sio-683、TD-600和TD-6408的氟磺胺草醚药液,测定药液对苘麻的抑制率及增效比;取苘麻6龄叶片,分别测定添加不同有机硅助剂后氟磺胺草醚药液的表面张力、在叶片上的扩展直径及最大持留量。结果表明：6种有机硅助剂对氟磺胺草醚的增效作用可达15.88%-23.04%;可以显著降低氟磺胺草醚药液的表面张力（由60.7 m N/m降至20-25 m N/m）,使药剂在叶片表面的最大持留量增加30%-70%,扩展直径由4.7 mm增至6.5-8.2 mm;其中,Agrowet 820增效作用最明显,可使表面张力降低65%,最大持留量增加69%,扩展直径增加74%,防效提高23.04%。

分散固相萃取-超高效液相色谱-串联质谱联用快速检测大豆及土壤中氟磺胺草醚残留

采用分散固相萃取(QuEChERS)样品前处理方法,建立了超高效液相色谱-串联质谱(UPLC-MS/MS)快速检测大豆和土壤中氟磺胺草醚的残留分析方法.大豆和土壤样品采用乙腈(含0.5%甲酸)提取,N-丙基乙二胺(PSA)或石墨化碳黑(GCB)净化,UPLC-MS/MS外标法检测定量.在0.005—0.5 mg.kg-1添加范围内,氟磺胺草醚在土壤、大豆和大豆植株中的平均回收率在79.4%—109.0%之间,变异系数在3.6%—10.1%之间.在山东、河南、吉林进行了氟磺胺草醚在大豆植株和土壤中的降解动态研究,结果表明,试验点中氟磺胺草醚在土壤中的降解半衰期为8.5—23.7 d;在大豆植株中的降解半衰期为2.7—9.8 d.

不同缓解处理对氟磺胺草醚大豆药害的缓解效果研究

为了研究氟磺胺草醚对大豆的药害情况以及不同缓解剂对药害的缓解作用,在大田大豆喷施氟磺胺草醚后,分2个时期分别喷施8种缓解剂,然后在特定时间分别调查大豆的株高、地上鲜重、叶绿素含量、单株荚数和产量。结果表明:高剂量氟磺胺草醚对大豆药害明显,大豆株高、地上鲜重分别降低16.89%、49.39%,叶绿素含量下降43.75%,单株荚数和产量也分别减少30.0%、14.24%。药害前期喷施宝叶、萘乙酸、赤霉酸和磷酸二氢钾或药害后期喷施宝叶、奈安、芸苔素内酯和氨基酸对大豆产量均有较好的缓解效果。综合分析,药害前期喷施萘乙酸、磷酸二氢钾更有利于大豆增产,其产量较未喷施氟磺胺草醚对照分别增加36.22%和29.88%,可用于修复药害对大豆生长发育造成的影响。

氟磺胺草醚降解菌的分离鉴定及生长特性研究

氟磺胺草醚广泛应用于大豆田防除阔叶杂草,其长残留问题十分严重,微生物降解是解决氟磺胺草醚残留问题的有效途径。利用高压富集的方法,从长期施用氟磺胺草醚的田间土壤中,分离筛选出6株能够以氟磺胺草醚为唯一碳源生长的降解菌,其中一个菌株在查氏液体培养基中培养5d,对40mg a.i./L氟磺胺草醚的降解率为92.13%。通过形态特征鉴定并对该菌株18S rRNA的部分序列进行基因测序,对其在系统发育分类学上的地位加以分析,同时研究环境条件对其生长的影响。结果表明,该菌株为真菌,初步鉴定为黄曲霉(Aspergillus flavus),实验室命名为TZ1985。菌株TZ1985最适生长温度为25℃,最适培养基pH值为7.0,生长最适葡萄糖含量为0.6%,生长最适氟磺胺草醚的浓度是10mg a.i./L。

氟磺胺草醚的生物测定方法研究

试验利用对氟磺胺草醚敏感的玉米、向日葵、高粱为指示作物,利用土培法研究了不同条件下,氟磺胺草醚不同浓度对作物的抑制作用,并建立了氟磺胺草醚玉米生物测定方法——玉米株高法。试验结果表明,最佳生物测定条件为在27℃条件下,培养120 h。研究结果对土壤中氟磺胺草醚的快速测定和轮作换茬具有重要意义。

pH对氟磺胺草醚水解的影响

采用试验分析方法研究了氟磺胺草醚在不同pH缓冲溶液中的水解作用。结果表明,随着溶液pH值的增大,氟磺胺草醚的水解反应逐渐减慢,速率常数K减小,半衰期相应地增大。氟磺胺草醚在pH为5.0、6.0、7.0、8.0、9.0的缓冲液中的水解半衰期分别为105.74、157.41、183.26、215.16、247.40 d。

不同玉米品种对氟磺胺草醚的敏感性差异

为评价氟磺胺草醚对玉米的安全性，采用室内毒土法和酶活力测定法探讨不同玉米品种对氟磺胺草醚的敏感性差异及其机制。不同玉米品种对氟磺胺草醚的敏感性有较大差异，其中，东农888对氟磺胺草醚最敏感，IC50为0.59 mg·kg^-1，其次为垦粘1号，耐药倍数仅为1.10；龙467、高油186、龙单38等8个品种的敏感性中等，耐药倍数为2.88～5.25；吉单27、先玉335等6个品种表现出较强的耐药性，耐药倍数为5.71～8.83，其中，吉单27、先玉335和东农888、垦粘1号对氟磺胺草醚敏感性差异显著。氟磺胺草醚对4种玉米的PPO活性、叶绿素含量及光合速率影响均随残留量增加而逐渐增大，氟磺胺草醚对玉米PPO活性、叶绿素含量及光合速率的抑制与品种的耐药性呈负相关。研究表明，不同玉米品种对氟磺胺草醚产生的敏感性差异源于PPO活性差异。

一株降解氟磺胺草醚的黑曲霉菌特性

从被氟磺胺草醚污染的土壤中筛选、富集培养了能够高效降解氟磺胺草醚的黑曲霉菌株S7。研究表明:低浓度氟磺胺草醚可促进黑曲霉菌株S7的生长,对氟磺胺草醚降解率较高;当氟磺胺草醚质量浓度在100mg/L情况下,碳源为1.0%,初始pH值为6,温度为28～36℃,接菌量为2%～3%,有利于黑曲霉菌株S7的生长、提高其活力,更利于对氟磺胺草醚的降解。

助剂对氟磺胺草醚除草活性及大豆安全性的影响

通过盆栽试验测定3种助剂(ZA、JA、FA)对氟磺胺草醚增效作用及大豆安全性影响。结果表明,3种助剂能显著增加氟磺胺草醚对反枝苋和龙葵的防除效果,对低剂量(<262.5 g·hm-2)水平下氟磺胺草醚增效作用高于高剂量水平(>375 g·hm-2);同一施药量水平下,FA增效作用高于JA和ZA,FA和JA间差异不显著,均显著高于ZA。添加助剂增加氟磺胺草醚对大豆表观药害症状,加重低剂量(262.5 g·hm-2)氟磺胺草醚对大豆生长抑制,不增加高剂量(>375 g·hm-2)氟磺胺草醚对大豆生长的抑制,3种助剂间差异不显著,不会影响药害恢复时间。

大豆苗后除草剂和表面活性剂多元混用的研究

在大豆田采用二次旋转回归设计测定了 3种大豆苗后除草剂 (虎威、苯达松、精喹禾灵 )和十二烷基苯磺酸钠 (ABS)、渗透剂JFC 5元混用的最佳配比和互作关系。药剂间的互作关系分别采用回归系数t测验法和变量轮换 -方差分析法测定。两种方法对除草剂间的互作关系判别结果一致。其结果表明 ,虎威 +苯达松对苘麻有增效作用 ,虎威 +精喹禾灵对反枝苋有拮抗作用 ,其余为相加作用或独立作用。对除草剂和表面活性剂的互作关系的评价结果 ,两种方法不一致。其原因是在不同剂量范围某些因素相互作用方式和程度有时有所不同。回归系数t测验表明的相互作用关系指的是整个试验剂量范围 ,而变量轮换 -方差分析法则能反映特定剂量内 (如最佳配比 )的相互作用关系。采用后者测定表明 ,在最佳配比范围内ABS和JFC与 3种除草剂组合有增效作用。采用微分法求混用的最佳配比 ,某些值会超出了试验水平范围 。

氟磺胺草醚对大豆根瘤固氮酶活性及光合速率的影响

采用田间试验的方法研究了氟磺胺草醚对大豆根瘤固氮酶活性和叶片光合速率的影响。结果表明,在喷药后的38d内,氟磺胺草醚263g/hm2和525g/hm2施药一次对光合速率的抑制率分别为:3.72%～18.164%和8.13%～23.41%,对固氮酶活性的抑制率分别为:33.93%～73.97%和44.44%～79.43%,且第38天对根瘤固氮酶活性的抑制率最高。氟磺胺草醚263+263g/hm2和525+525g/hm2施药两次对光合速率的抑制率分别为:5.07%～42.574%和7.30%～44.50%,对固氮酶活性抑制率分别为:14.66%～65.77%和22.08%～70.96%,第23天对固氮酶活性抑制率最高。