棉田除草活性化合物SIOC0426生物活性初步评价

SIOC0426 属2-嘧啶氧基-N-芳基苄胺类选择性除草活性化合物。室内生物活性测定结果表明,SIOC0426具有良好的芽后早期除草活性,对棉花安全,在棉花与重要杂草马唐和反枝苋之间的选择性系数分别为 3.534 和4.299,能有效防除棉花田禾本科杂草和阔叶杂草,对莎草科杂草也有一定抑制作用,使用适期为杂草1~2叶期。田间试验表明,在有效成分90~120 g/hm2剂量范围内,对棉田主要杂草的总防效在73.1% ~87.6%之间。     

Pyrimidinyl-substituted amides and thioureas: syntheses, crystal structure and herbicidal activities

BACKGROUND: The high herbicidal activities of [1,2,4]triazolo[1,5-c]pyrimidine and 2H-1,2,4-thiadiazolo[2,3-a]pyrimidine derivatives suggested the development of new fused heterocyclic compounds for application as herbicides. RESULTS: Three series of pyrimidinyl-substituted thioureas (4) and amides (5, 6) were synthesized, and the typical crystal structure of a 2H-1,2,4-thiadiazolo[2,3-a]pyrimidine derivative (5a) was determined by X-ray diffraction. All the compounds were tested for herbicidal activity against selected weeds. CONCLUSION: The series of fused heterocyclic amides 5a to 5d exhibited high herbicidal activities both against monocotyledonous weeds (Echinochloa crus-galli L., Sorghum bicolor (L.) M?nch., Digitaria sanguinalis (L.) Scop) and against dicotyledonous weeds (Amaranthus retroflexus L. and Brassica campestris L.) in pre-emergence treatments. In particular, compound 5b at low concentration still showed high inhibitory activity against A. retroflexus in pre-emergence treatment. Different substituents at the meta positions of the pyrimidine ring were found to affect the herbicidal activity.     

新型除草剂ZJ0862的研究与开发

以水杨醛、3,4-二氯苯胺和4,6-二甲氧基-2-甲砜基嘧啶为原料合成了新型除草剂ZJ0862 ,其结构经1H NMR、MS、IR和元素分析确证。室内生物测定试验表明,ZJ0862在有效成分60 g/hm2剂量下,对水田重要杂草稗草和异型莎草的抑制率达90%以上;在45 g/hm2剂量下,对看麦娘、野燕麦、狗尾草等15种田间常规杂草的抑制率达85%~100%,杀草谱较广;田间试验结果显示,ZJ0862在150 g/hm2剂量下对移栽水稻安全,且在 60~90 g/hm2剂量下对水田主要杂草水苋菜、陌上菜、异型莎草等的防效达81.3%~98.4%。毒理学评价结果显示,该药剂为低毒、无刺激、弱致敏和致突变阴性。ZJ0862具有高效、低毒、安全的特点,在移栽水田将具有较好的开发前景。     

Responses of annual bluegrass (Poa annua L.) and creeping bentgrass (Agrostis palustris Huds.) seedlings to nitrogen,phosphorus and potassium†

The growth response to fertilizer under different soil texture (light clayey soil and composite soil consisting of the light clayey soil and sand), and the timing of N fertilization (early summer and fall fertilization) were determined for annual bluegrass (Poa annua L.) and creeping bentgrass (Agrostis palustris Huds., var. Penncross) in glasshouse experiments. At the three‐leaf stage, both plant species were treated with 30, 100, 300, 1,000, 3000 or 10 000 p.p.m. (w/v) of N, P₂O₅ and K₂O equivalent to ammonium sulfate (N), calcium superphosphate (P) and potassium chloride (K). Three weeks after fertilization, the dry weight of shoots or roots was measured. Both plant species were more sensitive to N than to P or K; however, creeping bentgrass required a higher rate of N (1000 p.p.m.) for maximum shoot and root growth than did the weed (300 p.p.m., N). Shoot growth of both plant species was strongly affected by the timing of N fertilization and soil texture; their shoot responses to N increased in the order: composite soil > light clayey soil, and early summer N fertilization > fall N fertilization, and this tendency was especially marked for creeping bentgrass. These results suggest that the response of annual bluegrass to fertilizer is similar to that of creeping bentgrass; however, the two plants are different in regard to the N requirement or their relationship between response to N and application timing and/or soil texture.     

Investigation of an emulsifiable oil adjuvant and its components on the activity of a new grass herbicide by factorial experimentation

The herbicidal activity of a new compound [(±)-(EZ}-2-[1-allyloxy-imino)propyr]-3-hydroxy-6-(4-cyanophenyl)cyclohex-2-ene-1-one] (I) , selective to broad-leaf plants, and partially selective in some cereal crops was enhanced by an emulsifiable paraffinic oil (HVI 60E). In order to determine the amount of HVI 60E to be applied with an emulsifiable concentrate of I (IE) a factorial herbicidal assay involving six concentrations of I and five concentrations of HVI 60E (both sets including zero concentration) was conducted to obtain response surfaces of herbicidal activity. The total selectivity of IE in broad-leaf species remained for all HVI 60E concentrations. The activity against grass weeds, except Poa annua L., increased markedly with increasing HVI 60E concentration and enhancement of performance of IE by HVI 60E in broad-leaf crops could be pursued without fear of crop phytotoxicity. However, the increases in activity against grass weeds were accompanied by increases in phytotoxicity against cereal crops. The response surfaces of Echinochloa crus-galli(L.) Beauv. and Zea mays L. were coincident and this result terminated further testing in this outlet. However, the response surfaces of Avena fatua L. and Triticum aestivum L. were reasonably well separated. Further tests in this outlet and in broad-leaf crops are planned around optimum cost-performance ratios derived from combinations with cost-response surfaces. The results of a further lest showed that both components (oil and emulsifier) of HVI 60E were approximately equivalent in adjuvant enhancement activity and so, on cost grounds, a crop oil (low emulsifier content) would be preferred over a crop oil concentrate (high emulsifier content).     

Biological activity of the new herbicide LGC-40863 {benzophenone O-[2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoyl]oxime}

Herbicidal characteristics of the experimental compound LGC-40863 (ISO proposed common name: pyribenzoxim) were investigated in greenhouse and field. In the greenhouse, LGC-40863 had strong post-emergent activity on various grass and broadleaf weeds including Echinochloa crus-galli L. Beauv., Alopecurus myosuroides Huds. and Polygonum hydropiper L., while it was safe in rice (Oryza sativa L.), wheat (Triticum aestivum L.) and zoysiagrass (Zoysia japonica Steud; (a turf species). Among important rice weeds, E. crus-galli was controlled over a wide window from the one-leaf to the six-leaf stages. In the field, LGC-40863 provided excellent control of E. crus-galli (>95%) at 30 to 40 g ha^-1 when applied alone, or at 15 to 30 g ha^-1 when applied in combination with pendimethalin, while it did not cause injury to rice at up to 60 g ha^-1. These results suggest that LGC-40863 has potential as a new selective post-emergent herbicide in rice. © 1997 SCI     

Synthesis and herbicidal activity of new 3-(3-bromothiophen-2-yl)-5-(2,6-difluorobenzyl)oxymethyl-5-methyl-4,5-dihydroisoxazole as a paddy field herbicide

A new compound 3-(3-bromothiophen-2-yl)-5-(2,6-difluorobenzyl)oxymethyl-5-methyl-4,5-dihydroisoxazole was synthesized and the herbicidal activity was assessed under glasshouse and flooded paddy field conditions. This compound demonstrated good rice selectivity and potent herbicidal activity against annual weeds at 125 g ai ha⁻¹ under greenhouse conditions. Soil application of this compound showed the complete control of barnyardgrass to the 4th leaf stage at 250 g ai ha⁻¹. Field trials indicated that this compound, combined with pyrazosulfuron-ethyl, controlled annual and perennial weeds rapidly with good tolerance by transplanted rice seedlings from postemergence and soil application. This compound showed a low mammalian and environmental toxicity in various toxicological tests.     

新型酰胺类除草剂NC1的除草作用及对水稻的安全性

为了明确新型除草剂NC1的杀草谱、施药时期、使用剂量及对水稻的安全性,采用种子生物测定法测定34.5％ NCI悬浮剂对稗草的生物活性,并与30乡丙草胺乳油进行比较;采用室内整株生物测定法测定34.5％NC1 SC不同时期处理对禾本科杂草的控制作用和对水稻的安全性,并进行田间验证.结果 表明:NC1对稗草种子的生物活性优...     

黄花蒿叶醇提取物除草活性物质的分离及结构鉴定

为明确黄花蒿除草活性及活性物质的成分,本研究采用室内生测法测定了黄花蒿叶醇提物对4种杂草的活性;采用系统溶剂分离、硅胶柱层析分离及气质联用色谱法对提取物进行了分离和结构鉴定.结果 表明:5.0 mg/mL的黄花蒿叶醇提物对供试杂草发芽率、发芽势和发芽指数均有一定的抑制作用,抑制作用从大到小的顺序为反枝苋,苘麻,狗尾草,...     

Weed seed bank as affected by tillage,residue, and fertilization management under sweet corn-wheat cropping sequence in Iran

Soil weed seed bank is an important factor determining above-ground floristic composition and weed density in agricultural systems. The quantitative and qualitative measures of weed seed bank can help growers to predict the extent to which they are facing weed problems. Along with tillage, crop residues can affect the fate of weeds in the upcoming crops. To investigate such effects, we compared the effects of tillage systems [conventional tillage (CT), reduced tillage (RT), and no tillage (NT)], wheat residue retention, and nitrogen (N) rates (0, 69, 138, and 207 kg N ha⁻¹) on depth-related characteristics of the weed seed bank under a sweet corn-wheat sequence during 2014–2015 growing seasons in Shiraz, Iran. Soil bank was not affected by tillage systems but tended to be slightly higher under RT. The highest (898 seeds m⁻²) and lowest (322 seeds m⁻²) weed population at 0–10 cm depth were found when 138 kg N ha⁻¹ in 2015 and 207 kg N ha⁻¹ in 2014 were applied. Species richness and diversity were higher under NT and RT practices at the top layer, but CT system was more diversified at deeper depths. They were higher when crop residues were retained as well. Barnyard grass (Echinochloa crus-galli [L.] Beauv), common lambsquarter (Chenopodium album L.), common purslane (Portulaca oleracea L.), field bindweed (Convolvulus arvensis L.), flixweed (Descoreinia sofia [L.] Webb. & Berth.), henbit (Lamium amplexicaule L.), pigweeds (Amaranthus spp.), and stinking goosefoot (Chenopodium vulvaria L.) were the most common weeds found in all tillage systems and soil depths. Grasses were relatively lower than broadleaves regardless of treatments. Weed seed bank was mostly affected by weather conditions than treatments in this short-term experiment.     

Studies of the New Herbicide KIH-6127. Part III. Synthesis and Structure–Activity Studies of Analogues of KIH-6127 against Barnyard Grass (Echinochloa oryzicola)*

The previously evaluated prototype, methyl 6-acetyl-2-[(4,6-dimethoxypyrimidin-2-yl)oxy]benzoate, was modified by the introduction of an oximino group. Further extensive synthetic modifications were then made to the 6-alkyl moiety (R¹), the ester moiety (R²), the alkoxyimino moiety (R³), the bridge-atom (X) and the 4,6-disubstituted-pyrimidine moiety (A, B, Z). Structure–activity relationships of the synthesized compounds were studied by examining their herbicidal activity against Barnyard grass (Echinochloa oryzicola) in paddy rice at various growth stages, including pre-emergence. The novel herbicide methyl 2-[(4,6-dimethoxypyrimidin-2-yl)oxy]-6-[1-(methoxyimino)ethyl]benzoate, (KIH-6127) was found to be the most effective compound. The commercial development of this compound is currently in progress. © 1997 SCI.     

Studies of the New Herbicide KIH-6127. Part II. Synthesis and Herbicidal Activity of 6-Acyl Pyrimidin-2-yl Salicylates and Analogues against Barnyard Grass

The method reported previously (Part I) was employed to prepare a variety of novel 6-acylsalicylates as key intermediates. 6-Acylpyrimidin-2-yl salicylates (2-acyl-6-[(4,6-disubstituted pyrimidin-2-yl)oxy]benzoate derivatives: Type 1), the closely related phthalide compounds (3-alkyl-7-[(4,6-dimethoxypyrimidin-2-yl)oxy]phthalide derivatives: Type 2) and the ketal derivatives of 2-acyl-6-[(4,6-dimethoxypyrimidin-2-yl)oxy]benzoates (Type 3) were synthesized and their herbicidal activities measured. Methyl 2-acetyl-6-[(4,6-dimethoxypyrimidin-2-yl)oxy]benzoate gave excellent control of barnyard grass with a promising profile as a prototype rice herbicide.     

Studies on the selectivity of alloxydim-sodium in plants

Alloxydim-sodium, methyl 3-[1-(allyloxyimino)butyl]-4-hydroxy-6,6-dimethyl-2-oxocyclohex-3-enecarboxylate sodium salt, is a selective herbicide which controls grass weeds in a wide range of broad-leaf crops. Spray retention, tested at two growth stages, was generally greater for the broad-leaf crops (cotton, sugarbeet, flax, beans and peas) than for wild oat (Avena fatua L.), blackgrass (Alopecurus myosuroides Huds), barley and couch grass [Agropyron repens (L.) Beauv.], and did not contribute to selectivity between susceptible and tolerant species. Broad-leaf crops tolerated 2820 g alloxydim-sodium ha^?1, three times the recommended rate used to control annual grasses. Differential uptake and translocation were not factors contributing to selectivity. In wild oat, blackgrass and sugarbeet, uptake and translocation of ¹⁴C continued during a period of 14 days after treatment with [¹⁴C]alloxydim-sodium. Translocation in susceptible and tolerant species was predominately symplastic. Over 40% of the applied ¹⁴C was eliminated from treated wild oat, blackgrass and sugarbeet plants within 7 days, due to degradation and volatilisation. A greater proportion of the methanol-soluble radioactivity extracted from leaves and roots was present as water-soluble polar metabolites in sugarbeet, than in wild oats, 7 days after treatment. The proportion of unaltered alloxydim in the organo-soluble fraction of a methanol extract was greater in wild oat than in sugarbeet. Differential metabolism appears to be one of the factors contributing to alloxydim-sodium selectivity between sugarbeet and wild oat.     

Synthesis and herbicidal potential of substituted aurones

BACKGROUND: With the objective of exploring the herbicidal activity of substituted aurones, a series of 4,6‐disubstituted and 4,5,6‐trisubstituted aurones were synthesised, and their herbicidal activities against Brassica campestris L. and Echinochloa crusgalli (L.) Beauv. were evaluated in laboratory bioassays. Effects of some of the compounds were evaluated on seed germination. The most active compounds in the laboratory were evaluated in the greenhouse. RESULTS: The compounds were characterised by ¹H NMR, ¹³C NMR and HRMS; some of them were further identified by IR. A (Z)‐configuration was assigned to the aurones, based on spectroscopic and crystallographic data. Bioassay results of root growth showed that the aurones had a moderate herbicidal activity against the dicotyledonous plant Brassica campestris. (Z)‐2‐Phenylmethylene‐4,6‐dimethoxy‐3(2H)‐benzofuranone(6o) was the most active compound, with 81.3 and 88.5% inhibition at 10 and 100 µg ml^?1 respectively, equal to the activity of mesotrione. Some of the aurones possessed some inhibition of germination on several plant species. For glasshouse tests, the substituted aurones had lower herbicidal activity than metolachlor and mesotrione. CONCLUSION: It is possible that aurone derivatives, which possess structures different from those of the commercial herbicides, may become novel lead compounds for the development of herbicides against dicotyledonous weeds with further structure modification. Copyright © 2012 Society of Chemical Industry     

Novel 3,3a,5,9b-tetrahydro-2H-furo[3,2-c][2] benzopyran derivatives: synthesis of chiral glycol benzyl ether herbicides

Novel tricyclic 3,3a,5,9b-tetrahydro-2H-furo[3,2-c][2]benzopyran (TFB) derivatives were synthesized, and their herbicidal activities were elucidated. They were synthesized from D-glucose as a natural chiral source. The formation of the TFB skeleton was achieved by a Friedel-Crafts type intramolecular cyclization of methyl 5-deoxy-2,3-O-dibenzyl-5-C-methyl-D-xylofranosides. The intramolecular cyclization was dependent upon the electronic effects of the substituents at the C-2 benzyloxy group of methyl xylofranosides. Some TFBs exhibited a remarkable herbicidal activity to annual paddy weeds, such as Echinochloa sp, without injury to the rice.     

脐橙果园杂草对地表径流和土壤流失的影响

江西省赣州市是我国最大的脐橙主产区,但长期以来果园水土流失问题未得到有效解决。试验于2015年3-8月雨季分别在江西省赣县和信丰县2个县各选择1个脐橙果园进行,在每个试验区果园设置3个径流小区,每个小区为1个处理,分别是清耕裸露(CK)、全园保留杂草(T1)和杂草条带(T2),观测地表径流和土壤流失情况。共调查到45种果园杂草,分属27科43属,其中马唐和宽叶雀稗为优势草种。径流小区观测结果显示,与清耕裸露地相比,果园全园保留杂草和杂草条带能减少地表径流量15.5%~50.3%、土壤流失量30.9%~45.4%,T1处理减幅总体比T2处理大。表明脐橙果园杂草在防治果园水土流失方面发挥着重要作用,值得深入研究。     

双唑草腈的除草活性及对水稻的安全性

本文采用室内整株生测法测定了1.8%双唑草腈颗粒剂的除草活性及对不同水稻品种的安全性。在杂草出苗前、1叶期和2叶期以有效成分145.8g/hm2的剂量撒施1.8%双唑草腈颗粒剂对水稻田常见杂草稗草、鸭舌草、耳叶水苋和异型莎草的鲜重抑制率均在92%以上,药后3d杂草表现叶片干枯、黄化、僵苗等中毒症状,其见效速度明显快于对照药剂25g/L五氟磺草胺油悬浮剂。在水稻播后苗前或1叶期施用,其在‘南粳9108’(粳稻)、‘K两优10’(杂交稻)和稗草间的选择性指数均大于4,对水稻安全。     

Investigation on the transformation of fluchloralin by soil fungi: Identification of some metabolites

Fluchloralin [N-(2-chloroethyl)-α,α,α,-trifluoro-2,6-dinitro-N-propyl-p-toluidine] was transformed by two common soil fungi, Aspergillus flavus Link and Fusarium solani (Mart.) Sacc. in pure culture. The fungi were isolated from enrichment cultures of an analogous herbicidal compound, pendimethalin [N-(1-ethylpropyl)-2,6-dinitro-3,4-xylidine)]. Transformation of fluchloralin by these fungi resulted in the formation of several metabolites, 13 of which were identified. Besides the known mechanisms of microbial transformation of dinitroanilines, methylation of the anilino nitrogen and direct elimination of a nitro group at 2 position from the aromatic ring without any further substitution were also observed.     

Real-time weed detection, decision making and patch spraying in maize, sugarbeet, winter wheat and winter barley

Information on temporal and spatial variation in weed seedling populations within agricultural fields is very important for weed population assessment and management. Most of all, it allows a potential reduction in herbicide use, when post‐emergence herbicides are only applied to field sections with weed infestation levels higher than the economic weed threshold; a review of such work is provided. This paper presents a system for site‐specific weed control in sugarbeet (Beta vulgaris L.), maize (Zea mays L.), winter wheat (Triticum aestivum L.) and winter barley (Hordeum vulgare L.), including online weed detection using digital image analysis, computer‐based decision making and global positioning systems (GPS)‐controlled patch spraying. In a 4‐year study, herbicide use with this map‐based approach was reduced in winter cereals by 60% for herbicides against broad‐leaved weeds and 90% for grass weed herbicides. In sugarbeet and maize, average savings for grass weed herbicides were 78% in maize and 36% in sugarbeet. For herbicides against broad‐leaved weeds, 11% were saved in maize and 41% in sugarbeet.     

东北地区四种常见禾本科杂草病原真菌资源调查及其致病性测定

为了解我国东北地区常见禾本科杂草病原真菌资源状况,于禾草生长季节对东北三省19个县市的稗草、狗尾草、马唐和虎尾草的发病情况进行了调查和采样。对病害样品用组织分离法分离获得186个真菌菌株,经形态学观察和rDNA ITS序列比对分析,鉴定到10个属的真菌。对其中分离率较高具代表性的或来自发病严重样品的31个菌株用人工接种法进行了致病性测定,明确了新月弯孢(Curvularia lunata)对稗草、狗尾草、马唐和虎尾草均有较强致病性,梭形凸脐蠕孢(Exserohilum fusiforme)和尖角凸脐蠕孢(E. monoceras)对稗草具有较强致病性,麦根腐平脐蠕孢(Bipolaris sorokiniana)、狗尾草平脐蠕孢(B. setariae)、嘴突凸脐蠕孢(E. rostratum)和链格孢(Alternaria spp.)对狗尾草具有较强致病性。不同菌株致病性有差异,一般来讲,对原寄主的致病性强于对其他寄主的致病性。研究结果丰富了禾草的病菌资源和信息,为真菌除草剂的研发奠定了基础。