不同稗草种群对五氟磺草胺的敏感性差异

为探讨不同地区稗草种群对五氟磺草胺的敏感水平,采用室内整株生测法测定五氟磺草胺对不同稗草种群的生物活性以及对不同稗草种群叶绿素含量、光合特性、叶绿素荧光参数和Rubisco活性的影响。结果表明,五氟磺草胺影响稗草Rubisco活性、最大光化学效率以及光合速率等生理指标,但不同稗草种群的变化略有差异。其中五氟磺草胺处理后4 d对安徽潜山稗草种群生理指标影响较大,五氟磺草胺3.75~60.00 g a.i./hm~2处理剂量下稗草Rubisco活性较相同种群空白对照显著降低24.45%~61.09%,15.00~60.00 g a.i./hm~2剂量下,稗草叶片净光合速率较对照显著降低30.04%~58.56%,60.00 g a.i./hm~2剂量下,稗草叶绿素含量和最大光化合效率分别较对照显著降低13.10~28.82%和6.64%~11.29%,而湖北武汉稗草种群叶绿素含量、叶绿素荧光参数以及Rubisco活性无显著变化,只是叶片净光合速率较相同种群空白对照显著降低18.82%~28.49%。整株生物活性测定结果表明,五氟磺草胺处理21 d后安徽潜山稗草地上部鲜质量ED90值最低,为14.936 g a.i./hm~2,而湖北武汉稗草的ED90值最高,为201.679 g a.i./hm~2,显著超过了五氟磺草胺生产使用的推荐剂量。可见湖北武汉稗草种群对五氟磺草胺敏感性明显低于其他地区稗草种群,生产中需要密切注意其抗药性水平的发展变化,及时调整化学防除策略。     

广东省水稻田稗对五氟磺草胺的抗性分析

为明确广东省水稻田杂草稗Echinochloa crus-galli对五氟磺草胺的抗性现状及其可能的抗性机理,采用整株剂量反应法测定不同地区稗种群对五氟磺草胺的抗性水平,对不同稗种群的乙酰乳酸合成酶（acetolactate synthase,ALS）基因片段进行扩增测序,分析细胞色素P450酶（cytochrome P450 monooxygenase,P450）和谷胱甘肽-S-转移酶（glutathione-S-transferase,GST）抑制剂胡椒基丁醚（piperonylbutoxide,PBO）和4-氯-7-硝基-2,1,3-苯并氧杂噁二唑（4-chloro-7-nitro-1,2,3-benzoxadiazole,NBD-Cl）对不同稗种群抗性水平的影响,并对替代药剂进行筛选。结果显示,广东省水稻田多数稗种群对五氟磺草胺仍表现敏感,但采自湛江市的1个种群BC-7对五氟磺草胺产生了抗性,抗性倍数达6.5倍。与敏感种群BC-2相比,BC-7种群并未发生已报道的ALS靶标抗性相关突变。PBO和NBD-Cl均可显著提高BC-7种群对五氟磺草胺的敏感性,其干重抑制中量GR₅₀由31.1 g/hm²分别降为11.0 g/hm²和24.7 g/hm²。BC-7种群对氰氟草酯和噁唑酰草胺仍较敏感,但对二氯喹啉酸和双草醚产生了抗性。表明P450和GST介导的代谢抗性是稗BC-7种群产生抗性的重要原因,氰氟草酯和噁唑酰草胺适用于治理该抗性种群。     

稻田稗属杂草田间种群对五氟磺草胺的抗性监测

五氟磺草胺是一种乙酰乳酸合成酶抑制剂类除草剂.为探明稻田稗草对五氟磺草胺的抗性现状,采用整株生物测定法测定了采自中国7省70地稻区的稗草田间种群对五氟磺草胺的抗性.结果表明:所监测的稗草种群对五氟磺草胺均产生了不同程度的抗性,其中高水平抗性种群达50.0％,中水平抗性种群达47.1％,低水平抗性种群为2.9％,无敏感种...     

宁夏地区稗草种群对五氟磺草胺的抗性机制研究

为了明确宁夏稻区稗草对五氟磺草胺抗性水平及抗性机制。采用整株生物测定法测定了宁夏地区6个稗的原变种Echinochloa crus-galli var.crus-galli种群对五氟磺草胺的抗性水平,并测定了每个种群的乙酰乳酸合酶基因(ALS)序列和ALS酶离体活性,以及P450抑制剂马拉硫磷对稗草种群抗性水平的影响。结果显示,与敏感种群相比,5个疑似抗性种群对五氟磺草胺表现出不同程度的抗性(10.18倍～32.71倍),其中抗性种群N14,N22,N27和N51的ALS 574位色氨酸突变为亮氨酸,N53的197位脯氨酸突变为亮氨酸,敏感种群N43没有发现突变位点,五氟磺草胺对抗性种群ALS酶的IC₅₀均明显高于敏感种群,马拉硫磷对五氟磺草胺有增效作用,可提高稗草种群对五氟磺草胺的敏感性。综上所述,稗草种群对五氟磺草胺产生抗性是由于靶标基因ALS突变,同时稗草种群对五氟磺草胺的抗性也可能与细胞色素P450介导的代谢增强有关。     

五氟磺草胺防除水直播稻田杂草效果

2.5%五氟磺草胺油悬浮剂(稻杰)是美国陶氏益农公司生产的新型稻田除草剂,为了验证其对直播稻田杂草的防除效果,2004年我们进行了田间试验,现将试验结果报告如下。1材料与方法1.1供试药剂2.5%五氟磺草胺油悬浮剂(稻杰,美国陶氏益农公司生产);36%苄·二氯(秧草净可湿性粉剂,江苏常隆化工有限公司生产)。1.2试验设计试验共设5个处理:2.5%五氟磺草胺油悬浮剂40ml/667m2、60ml/667m2、80ml/667m2,36%秧草净40g/667m2,以不用药为对照。1.3试验概况试验田设在武进区礼嘉镇新路村施文明的承包田中,前茬为小麦。水稻品种为银玉2084,于6月6日上午人工…     

五氟磺草胺防除水直播稻田杂草的效果

五氟磺草胺(DE-638)是美国陶氏益农公司研制生产的新型除草剂。为了明确其对水直播稻田杂草的防除效果及对水稻的安全性,特进行本试验。1材料与方法1.1供试药剂供试药剂有2.5%五氟磺草胺油悬剂(美国陶氏益农公司生产)、50%杀稗王可湿性粉剂(江苏省激素研究所生产)、10%苄磺隆可湿性粉剂(江苏快达农化股份有限公司生产)。1.2试验设计试验设药土法和喷雾法两种用药方法。药土法设2.5%五氟磺草胺油悬剂40 m l/667m2、60m l/667m2、80 m l/667m2、100 m l/667m2,2.5%五氟磺草胺油悬剂60 m l/667m2 10%苄磺隆20g/667m2,50%杀稗王30 g/667m2 10%…     

五氟磺草胺·氰氟草酯OF对水直播稻田杂草的防除效果

6%五氟磺草胺·氰氟草酯OF是陶氏益农公司开发的直播田新型除草剂.田间试验结果表明,五氟磺草胺·氰氟草酯OF对水稻田中禾本科杂草、阔叶草及莎草科杂草的防效良好.在60.0～180.0 g(ai)/hm2量范围内对水稻安全,不影响水稻的生长和发育.其适宜的施用剂量为90.0～120.0 g(ai)/hm2,施药适期为水稻3～5叶期,稗革3～4叶期,千金子2～3叶期.     

2.5%五氟磺草胺悬浮剂+10%氰氟草酯乳油防除晚稻机插田杂草试验

试验结果表明:每667m2施用2.5%五氟磺草胺SC 40ml+10%氰氟草酯EC 40ml防除机插稻田杂草,对稗草、千金子、双穗雀稗、鸭舌草、节节菜、水苋菜、陌上菜和母草有较好的防除效果,防效达91%~100%,尤其对千金子防效优异。     

稻稗HJHL-715种群对五氟磺草胺的抗药性水平及抗性机理分析

为明确东北稻区稻稗Echinochloa oryzoides HJHL-715种群对五氟磺草胺的抗性水平及抗性机制,采用整株生物测定法测定稻稗种群对五氟磺草胺的敏感性,明确抗性种群的交互抗性和多抗性情况,研究3种细胞色素P450抑制剂对其敏感性的影响;并应用分子生物学方法进行稻稗的乙酰乳酸合酶(acetolactate synthase,ALS)离体活性测定、ALS基因序列分析及其表达量测定。结果表明:在东北稻区,五氟磺草胺对稻稗HJHL-715种群鲜重的抑制中剂量GR50为62.53 g/hm^2;稻稗HJHL-715的ALS基因序列中未发现氨基酸突变,其ALS离体活性与敏感种群的ALS离体活性无显著性差异,ALS基因表达量显著低于敏感种群。1-氨基苯并三唑(1-aminobenzotriazole,ABT)、胡椒基丁醚(piperomyl butoxide,PBO)、马拉硫磷3种P450抑制剂显著提高了稻稗HJHL-715种群对五氟磺草胺的敏感性,使其对五氟磺草胺的GR50由原来的62.53 g/hm^2分别下降到5.78、5.02、3.53 g/hm^2。表明东北稻区已经出现了对五氟磺草胺具有高水平抗性的稻稗种群,稻稗HJHL-715种群对五氟磺草胺的抗性很可能是由细胞色素P450介导的代谢增强所致。     

五氟磺草胺与吡氟酰草胺的联合作用及对水稻移栽田杂草的防效

吡氟酰草胺属于类胡萝卜素生物合成抑制剂类除草剂,为明确其与乙酰乳酸合成酶抑制剂类除草剂五氟磺草胺复配的联合作用及复配剂对水稻移栽田杂草的田间防效,采用温室盆栽法,评价了二者复配后的除草活性及联合作用类型,并通过田间小区试验评价了复配制剂对水稻田杂草的防效和对水稻的安全性。温室盆栽试验结果表明：五氟磺草胺与吡氟酰草胺复配后对稗、马唐、异型莎草及鳢肠的活性均表现为相加作用,二者复配的合适配比(质量比)范围为(1～2):(5～10)。田间小区试验结果表明,于水稻移栽后8 d茎叶喷雾处理,300 g/L五氟磺草胺·吡氟酰草胺(1:5)悬浮剂对水稻生长安全,且对水稻田稗、异型莎草、耳叶水苋及丁香蓼有良好的防效：在有效成分用量112.5～135.0 g/hm²剂量下,药后35 d,复配悬浮剂对上述杂草的总草株防效和总草鲜重防效分别为93.8%～95.8%和94.1%～96.1%,尤其是显著提高了对较难防除型杂草耳叶水苋及丁香蓼的防效,整体防效显著高于对照两个单剂处理及当地常规用药22%苄嘧磺隆·乙草胺可湿性粉剂处理。五氟磺草胺与吡氟酰草胺复配能够在扩大杀草谱的同时提高防效,且...     

Resistance of barnyardgrass (Echinochloa crus-galli) to atrazine and quinclorac

Two populations of Echinochloa crus-galli (R and I) exhibited resistance to quinclorac. Another population (X) exhibited resistance to quinclorac and atrazine. The R and I populations were collected from monocultures of rice in southern Spain. The X population was collected from maize fields subjected to the application of atrazine over several years. The susceptible (S) population of the same genus was collected from locations which had never been treated with herbicides. The quinclorac ED₅₀ value (dose causing 50% reduction in shoot fresh weight) for the R and I biotypes were 26- and 6-fold greater than for the S biotype. The X biotype was 10 times more tolerant to quinclorac than the S biotype and also showed cross-resistance to atrazine, being 82-fold more resistant to atrazine than the R, I and S biotypes. Chlorophyll fluorescence and Hill reaction analysis supported the view that the mechanism of resistance to atrazine in the X biotype was modification of the target site, the DI protein. Quinclorac at 20 mg litre^-1 did not inhibit photosynthetic electron transport in any of the test biotypes. The quinclorac I₅₀ values (herbicide dose needed for 50% Hill reaction reduction) of the S population was over 50000-fold higher than the atrazine I₅₀ value for the same S population, indicating that quinclorac is not a PS II inhibiting herbicide. Propanil at doses greater than 0·5 kg ha^-1 controlled all the biotypes. © 1997 SCI     

Herbicide-resistant barnyardgrass (Echinochloa crus-galli) in global rice production

Barnyardgrass (Echinochloa crus-galli (L.) Beauv.), an annual species of the family Poaceae, is a major weed problem in rice-producing countries throughout the globe. Synthetic herbicides can effectively control this grass in rice paddies, but the development of resistant biotypes after the continuous use of the same active ingredients has led to low herbicide efficacy and yield losses. In this review, a summary of resistant-barnyardgrass cases in global rice production is reported based on data from the International Herbicide-Resistant Weed Database. The first case of resistant barnyardgrass in rice paddies was to the photosystem-II inhibitor propanil in the late 1980s. Eighty-five (85) out of 116 cases in the period from 1986 to 2022 refer to resistant barnyardgrass (E. crus-galli var. crus-galli, E. crus-galli var. formosensis and E. crus-galli var. zelayensis) in 16 countries. Barnyardgrass has been found resistant to acetolactate synthase (ALS) inhibitors (34 cases), acetyl-CoA carboxylase (ACCase) inhibitors (23 cases), photosystem-II inhibitors (11 cases), auxin mimics/cellulose biosynthesis inhibitors (9 cases), very long chain fatty acid inhibitors (6 cases), and microtubule assembly inhibitors (1 case). The majority of all resistance cases reported to the active ingredients penoxsulam, bispyribac-sodium, and imazamox (ALS inhibitors), cyhalofop-butyl and fenoxaprop-ethyl (ACCase inhibitors), propanil (photosystem-II inhibitors), and quinclorac (auxin mimics/cellulose biosynthesis inhibitors). Although target-site resistance with specific mutations has been identified, non-target site resistance mainly through herbicide detoxification is also of great concern increasing the chance of multiple herbicide resistance evolution. Rotation of herbicides should be adopted concerning the modes of action used as well as the application methods to mitigate resistance evolution of this weed in rice paddies.     

Effect of temperature on herbicidal properties of MTB-951, a mycoherbicide to control Echinochloa crus-galli L.

MTB-951 is a potential mycoherbicide using a fungal plant pathogen ( Drechslera monoceras ) isolated from native Echinochloa species in Japan. Conidia of this pathogen were used as the active ingredient and the effect of temperature on its properties was examined in a laboratory. The optimum temperature for conidium germination was broad between 15 and 35°C and no difference in the germination ratio existed within this temperature range. Mycelial growth was the fastest at 25°C but was slower outside of the range 15–35°C. When leaves of Echinochloa crus-galli L. were immersed in deionized water containing the conidia, cellular electrolyte leakage from the leaves was observed. However, no electrolyte leakage occurred from leaves of rice ( Oryza sativa L.) under the same conditions. The occurrence of electrolyte leakage from E. crus-galli was dependent on the temperature and was the highest at 25°C. Herbicidal activity of MTB-951 against E. crus-galli was high between 25°C and 30°C, but decreased at 35°C in a glass vessel. In the present study, it was revealed that the physiological and herbicidal properties of MTB-951 depended on the temperature.     

稗草生防菌新月弯孢菌株J15（2）的生物学特性

研究了分离自稗草上的一个致病菌新月弯孢Curvularia lunata菌株J15（2）的基本生物学特性。结果表明,该菌菌丝生长、产孢的最适温度为28～32℃,pH为6～8。菌丝生长对光照无要求,黑暗利于增加产孢量,培养至15d可达产孢高峰。碳、氮、磷和硫等元素是该菌菌丝体生长、产孢的必需元素,钾、镁和铁对菌丝体的生长、产孢有极大的促进作用。分生孢子萌发的适宜温度范围为20～35℃,最适温度28℃;适宜培养基初始pH值在4～10之间。在58℃下,分生孢子10min失活。     

Annual cycles of germinability and differences between primary and secondary dormancy in buried seeds of Echinochloa crus-galli

The seasonal changes in percentage of dormant seeds of Echinochloa crus-galli in the field were recorded for 4 years. The lots of seeds were wrapped in nylon fabric, buried 20 cm under the grass sward and exhumed at monthly intervals. The proportion of seeds germinating under light conditions at a constant temperature of 25 °C fluctuated between 0% and 96%, with maxima in May–July and minima in September–November. Small between-year differences in the course of summer dormancy induction and its winter termination were probably caused by variation of weather conditions.
Attributes of dormancy innate to seeds after maturation (primary dormancy) and dormancy induced in buried seeds during the summer (secondary dormancy) were compared by investigating the rate of dormancy termination during storage of (a) dry seeds at 25 °C, (b) imbibed seeds at 5°C and (c) in seeds buried under field conditions during October–June. Percentage of germination increased faster in secondary than primary dormant seeds at both constant 25 °C and 5 °C. The seeds with primary and secondary dormancy also differed in the response to `germination pre-treatment', a 10-day exposure of imbibed seeds at 25 °C that causes germination of the non-dormant fraction of seed materials. After this treatment the time to resuming germination in primary dormant seeds was substantially increased, whereas the secondary dormant seeds were much less affected. Annual variation in the proportion of germinable seeds explains the low efficiency of autumn soil cultivation for decreasing reserves of E. crus-galli seeds in the soil.     

Influence of water management, application timing and temperature on efficacy of MTB-951, a mycoherbicide using Drechslera monoceras to control Echinochloa crus-galli L.

MTB-951 is a potential mycoherbicide using a fungal plant pathogen ( Drechslera monoceras ) isolated from native Echinochloa species in Japan. Conidia of this pathogen were used as the active ingredient and its herbicidal performance was examined in a greenhouse. The efficacy of MTB-951 on Echinochloa crus-galli L. was higher in deep water (7–9 cm) than in relatively shallow water (3–5 cm). In a postemergence application, the efficacy decreased as the leaf stage of E. crus-galli proceeded between the 1 and 2.5 leaf stage. For example, the control ratio (%) of E. crus-galli was 95% when applied at the 1 leaf stage, and 72% at the 2.5 leaf stage in 5 cm water. Generally, mycoherbicidal efficacy was less when applied pre-emergence rather than postemergence. Efficacy was also influenced by the duration of submergence in deep water. For example, when water depth was kept at 5 cm for more than 7 days after application and then decreased down to 3 cm, the efficacy was high. However, when the water depth was kept at 5 cm for less than 7 days, the efficacy was low. Efficacy was lower under high temperatures (35°C/25°C, day/night) than under low temperatures (25°C/15°C, day/night). Water management, application timing and temperature are important factors on herbicidal efficacy of MTB-951 to control E. crus-galli .     

Effects of oxadiargyl on direct-seeded rice and Echinochloa crus-galli under aerobic and anaerobic conditions

Dose–response experiments were conducted in glasshouse pot experiments to investigate the selectivity of oxadiargyl, a recently introduced herbicide, in direct‐seeded rice under both aerobic and anaerobic conditions. Crop sensitivity to oxadiargyl was comparatively greater for wet‐seeded (anaerobic) than for dry‐seeded rice (aerobic). Likewise, greater efficacy against Echinochloa crus‐galli (L.) was also observed under anaerobic conditions. These results indicate greater activity of oxadiargyl under anaerobic conditions, but that application pre‐sowing with subsequent flooding would reduce selectivity in wet‐seeded rice. The results are discussed in relation to rice production in Mediterranean agriculture.