Efficacy of postemergence herbicides tankmixes in aryloxyphenoxypropionate-resistant grain sorghum

The development of aryloxyphenoxypropionate (APP)-resistant grain sorghum could provide additional opportunities for postemergence herbicide grass control in grain sorghum. Field experiments were conducted in Texas (Bushland, and Yoakum), Kansas (Dodge City, Garden City, Hays, Manhattan, Colby, Ottawa, and Tribune), and South Dakota (Highmore) to evaluate the efficacy of quizalofop tank mixes in APP-resistant grain sorghum. Quizalofop was applied alone or in combination with dicamba, 2,4-D, prosulfuron, 2,4-D + metsulfuron methyl, or halosulfuron methyl + dicamba. Herbicides were applied when sorghum was 12–50 cm in height. Overall weed control was greater when quizalofop was applied with other herbicides than when applied alone. At 2 and 4 weeks after treatment (WAT), large crabgrass [Digitaria sanguinalis (L.) Scop.], giant foxtail (Setaria faberi Herrm.), and green foxtail [Setaria viridis (L.) Beauv.] control were greater than 90% when quizalofop was applied alone or in combination with dicamba, halosulfuron methyl + dicamba, or prosulfuron. Palmer amaranth (Amaranthus palmeri S. Wats.), puncturevine (Tribulus terrestris L.), and tumble pigweed (Amaranthus albus L.) control were greater than 90% in all treatments except when quizalofop was applied alone. Herbicide treatments, except those that included 2,4-D, caused slight to no sorghum injury. Grain sorghum yield was greater for all herbicide treatments compared to the weedy check. This research showed that application of quizalofop in combination with broadleaf weed herbicides provided excellent weed control in sorghum.     

我国抗ALS类除草剂油菜种质创制与研究进展

化学除草是控制田间草害的有效手段,但我国油菜化除面积非常有限。创制对特定除草剂具有选择抗性的油菜新种质,选育抗性品种是实现我国油菜化除的有效途径。乙酰乳酸合酶(acetolactate synthase,ALS) 类除草剂具有高效低量、选择性强、杀草谱广等优点,在生产上得到广泛应用。本文简述了ALS 基因及其突变产生抗性的机制,着重介绍我国基于ALS靶酶突变的抗除草剂油菜种质创制、抗性生理生化和分子机理等方面的研究进展,并探讨了抗除草剂新种质在油菜抗性新品种选育、杂交油菜制种及抗性基因在转基因工程中的应用。     

Effects of sulfosulfuron soil residues on barley (Hordeum vulgare), sunflower (Helianthus annuus) and common vetch (vicia sativa)

The phytotoxicity and sensitivity of succeeding crops to the new sulfonylurea, sulfosulfuron, have been reported although there is insufficient data on the phytotoxic effect of field soil residues. Growth chamber bioassays were conducted to detect the presence of residues in soil samples previously treated with sulfosulfuron at the recommended rate and double rate (20 and 40 g a.i./ha) that could affect the succeeding crop. Soil samples were collected between 7 and 9 months after sulfosulfuron application in field selectivity assays at nine different locations in Northern and Central Spain. The bioassay test species were barley (Hordeum vulgare L.) ‘Graphic’, sunflower (Helianthus annuus L.) ‘Albasol’ and common vetch (Vicia sativa L.) ‘Neska’, typical crops grown in rotation with wheat (Triticum aestivum L.) in this area. Sulfosulfuron residues did not affect barley and common vetch, but inhibited shoot length, root length and root dry weight of sunflower seeded into some soils treated with the 2× rate (40 g a.i/ha) 9 months earlier.     

禾宁防治豆田杂草试验总结

禾宁通用名精喹禾灵,主要用于防除豆田禾本科杂草,本试验通过每亩施用不同量的10.8%的禾宁,比较其防除效果及对大豆的安全性,为今后的大面积推广提供科学的依据。     

Evaluation of post-emergence herbicides for the control of wild oat (Avena fatua L.) in wheat and barley in Argentina

Wild oat (Avena fatua L.) is the most troublesome weed in cereal crops in Argentina. With the aim of studying the effects of different herbicides, doses, and wild oat growth stage at application on weed control and crop yield, field experiments were conducted in wheat and barley crops during three growing seasons in the south of Buenos Aires Province, Argentina. Treatments were post-emergence applications of new herbicide, pinoxaden + cloquintocet mexyl (5%-1.25%), at doses that ranged from 20 g to 60 g a.i. pinoxaden ha⁻¹, applied at two to three leaves and the beginning of tillering of wild oat. In addition, standard treatments were included and applied at the same wild oat growth stages. Diclofop methyl at 511 g a.i. ha⁻¹ and fenoxaprop-p-ethyl at 55 g a.i. ha⁻¹ were applied in barley. In wheat, diclofop methyl was replaced by clodinafop-propargyl + cloquintocet mexyl (24%-6%) at 36 g a.i. clodinafop-propargyl + 9 g cloquintocet mexyl ha⁻¹ and in 2008/09 wheat experiments, iodosulfuron plus metsulfuron methyl (5%-60%) at 3.75 g a.i. ha⁻¹ + 3 g a.i. ha⁻¹ also was included. In both crops, pinoxaden at 30 g a.i. ha⁻¹ and at higher rates, fenoxaprop-p-ethyl and clodinafop-propargyl gave the best control of wild oat. In 2006/07 wheat crops, treatments applied at tiller initiation provided better control than the early timing averaged across herbicides. However, wheat yield generally was greater with early application. In barley, wild oat control and crop yield were similar regarding time of application. Variations in crop yield were correlated with grain number m⁻² both in wheat and barley, but relationships between both grain number and spikes m⁻² and with grains per spike were identified only in wheat.     

大豆生产田杂草防除及存在的问题

在大豆集约化生产中，杂草防除是一个极为重要的问题。大豆生产田应在人工除草和机械除草的基础上，在兼顾生态环境的前提下，适当提倡化学除草，做到高效率、低残留，降低农民的劳动强度和生产成本，从而提高大豆的国际竞争力。     

Weed control in sunn hemp and its ability to suppress weed growth

Sunn hemp is a tropical, herbaceous annual legume that has potential as a cover crop during the summer in temperate climates. Due to the recent increased interest in sunn hemp breeding and seed production for temperate climates, there is a need for weed control in sunn hemp production. No herbicide product currently on the market specifically identifies sunn hemp as a tolerant crop. The aims of this research were 1) to evaluate herbicides with the intent of identifying a herbicide program that can assure near weed free sunn hemp intended for seed harvest and 2) to demonstrate and quantify sunn hemp-weed suppression. Pre-emergence applied treatments consisted of pendimethalin alone, imazethapyr alone, and pendimethalin plus imazethapyr. Pendimethalin alone provided consistent effective weed control and maximum sunn hemp biomass, but when yellow nutsedge was present, imazethapyr was required for effective control and greater sunn hemp biomass. The combination of pendimethalin and imazethapyr was detrimental to sunn hemp biomass yield. Results also established that sunn hemp is tolerant of 2,4-DB applied post-emergence, but was not necessary for weed control in these studies because of the lack of broadleaf weed pressure. In a separate study with variable sunn hemp densities, weed biomass reductions of ≥50% were obtained with sunn hemp densities of only 20 to 50 plants m⁻². This degree of weed suppression obtained from relatively modest sunn hemp densities is likely indicative of the ability of sunn hemp to grow faster and taller than other plants.     

Weed control and potato (Solanum tuberosum) tolerance with dimethenamid isomers and other herbicides

Two research studies were conducted to evaluate weed control in potato with dimethenamid and dimethenamid-p. No significant injury was observed from most applications of dimethenamid prior to potato emergence, but injury was 20% to 38% with dimethenamid when emerging potatoes were covered slightly by soil during “drag-off” and rain occurred within 24 h. Common lambsquarters (Chenopodium album L.) and common ragweed (Ambrosia artemisiifolia L.) control with dimethenamid preemergence (PRE) did not exceed 68%. Dimethenamid-p plus metribuzin or dimethenamid-p followed by (fb) rimsulfuron postemergence (POST) controlled common lambsquarters 95% to 96% and common ragweed 71% to 92%. Annual grass control was greater with S-metolachlor alone than with dimethenamid isomers alone. Broadleaf and grass control was similar with dimethenamid and dimethenamid-p.     

Weed control with pre-emergence herbicides in vegetable soybean (Glycine max L. Merrill)

Field and laboratory experiments were conducted in the early and late rainy seasons in Thailand to evaluate the effect of pre-emergence application of herbicides and determine the herbicide residues on vegetable soybean (Glycine max L. Merrill cv. No. 75) production. No visible crop injury was observed after application of alachlor 469 g a.i./ha, clomazone 1080 g a.i./ha, metribuzin 525 g a.i./ha, pendimethalin 1031.25 g a.i./ha, tank-mixed clomazone 960 g a.i./ha + pendimethalin 928 g a.i./ha, or tank-mixed metribuzin 350 g a.i./ha + pendimethalin 928 g a.i./ha. However, acetochlor 1875 g a.i./ha, isoxaflutole 75 g a.i./ha, and oxadiazon 1000 g a.i./ha caused visible crop injury. Plant bioassay of herbicide residues in the soil after harvest showed no phytotoxic effect on baby corn (Zea mays Linn. cv. Suwan 3), cucumber (Cucumis sativus L. cv. Pijit 1), pak choi (Brassica chinensis Jusl. cv. Chinensis), and soybean (G. max L. Merrill cv. CM 60). Gas Chromatography-Mass Spectrometry (GC–MS) analysis showed no significant herbicide residues on crop yield (or MRLs < 0.01 ppm) for all herbicides used in this study. The application of metribuzin at 525 g a.i./ha was sufficient to provide satisfactory full-season control of several weed species and gave the highest crop yield. In addition, pendimethalin at 1031.25 g a.i./ha, and tank-mixed metribuzin at 350 g a.i./ha + pendimethalin at 928 g a.i./ha can provide a similar level of weed control as an alternative to reduce herbicide dosage thereby increasing food and environmental safety in vegetable soybean production.     

大豆除草剂对水稻秧苗生长的影响

就施过豆磺隆、普施特、广灭灵的大豆茬,对后作水稻本田秧苗生长的影响进行研究。结果表明:各处理对水稻移栽后的幼苗生长发育都有程度不同的影响。     

大豆除草剂对水稻秧苗生长的影响

就施过豆磺隆、普施特、广灭灵的大豆茬,对后作水稻本田秧苗生长的影响进行研究。结果表明：各处理对水稻移栽后的幼苗生长发育都有程度不同的影响。     

作保灵对磺酰脲类除草剂解毒效应的研究

利用田间试验方法研究保护剂对磺酰脲类除草剂解毒效应.作保灵浸种和拌种处理能保护玉米免受豆磺隆残留药害,而且拌种处理优于浸种处理;玉米不同品种对绿磺隆残留反应不同,不同品种间作保灵对绿磺隆解毒作用有差异;作保灵拌种对玉米生长发育无任何影响。     

大豆田除草剂混用技术及药害

为了指导大豆田杂草防除技术,介绍了大豆田杂草发生的主要种类与特点,除草剂混用品种的选择,除草剂药害的分类,除草剂药害调查分级与除草剂混用性能比较等,以及大豆田杂草防除技术和施用除草剂混剂不当造成的药害.     

Weed control in rice seedling nurseries

Experiments were conducted in farmers' fields at Guimba, Nueva Ecija and at the International Rice Research Institute (IRRI), Los Baños, Laguna to test the efficacy of different methods of controlling weeds in rice (Oryza sativa L.) seedling nurseries. Hand weeding was laborious and ineffective due to the morphological similarities between rice and the Echinochloa species and the regeneration of perennial weeds. It was also injurious to rice seedlings. Manual separation of weed seedlings from rice seedlings before transplanting was ineffective, laborious, time consuming and expensive. Thiobencarb, butachlor, pretilachlor+fenclorim, propanil and quinclorac+bensulfuron were inexpensive and effective in controlling weeds in seedling nurseries without any deleterious effect on rice.     

Weed control and sesame (Sesamum indicum L.) response to preplant incorporated herbicides and method of incorporation

Field studies were conducted at two sesame-growing regions of Texas in 2004 and 2005 to determine weed control and sesame response to four dinitroaniline herbicides and their method of incorporation. Ethalfluralin, pendimethalin (formulated as Prowl EC), and trifluralin were applied at the X, 1X, and 2X of the suggested label dose for Gossypium hirsutum L. Pendimethalin (formulated as Prowl H₂O) was applied at the X, 1X, and 1X rate. Two methods of incorporation included rolling cultivator mixing wheels and spring tooth harrow. With rolling cultivator mixing wheels, all herbicides controlled Amaranthus tuberculatus (Moq.) J.D. Sauer at least 74% regardless of dose. The X dose of ethalfluralin and pendimethalin (formulated as Prowl EC), or the X and 1X dose of pendimethalin (formulated as Prowl H₂O) controlled Brachiaria platyphylla (Griseb.) Nash no better than 73% while all other doses of the herbicides controlled B. platyphylla at least 80%. The use of mixing wheels to incorporate the herbicides resulted in better sesame stands and less stunting than the use of the spring tooth harrow; however, sesame stands were reduced as herbicide rate increased when using mixing wheels. Ethalfluralin at the 1X dose, pendimethalin (formulated as Prowl H₂O) at the X dose, and trifluralin at the X dose produced the highest sesame yield while ethalfluralin at the 2X dose produced the lowest yield.     

Integrated effect of allelochemicals and herbicides on weed suppression and soil microbial activity in wheat (Triticum aestivum L.)

To evaluate the allelopathic effects of major crops and weeds, studies were conducted during 2011–12 and 2012–13 by utilizing water extracts of allelopathic plants namely rice (Oryza sativa L.), Parthenium hysterophorus L., Phragmites australis Cav., and Datura alba L. with reduced rates of fenoxaprop-p-ethyl and bromoxynil plus MCPA to control weeds. Application of Phragmites australis and Parthenium hysterophorus along with lower rates of fenoxaprop-p-ethyl and bromoxynil plus MCPA showed promising results by controlling weeds and improving yield. Parthenium hysterophorus extract with half of the recommended dose of fenoxaprop-p-ethyl and bromoxynil plus MCPA reduced weed density by 51 and 50% during year 1 and year 2, respectively, compared with the control. Phragmites australis extract with half of the recommended dose of fenoxaprop-p-ethyl produced grain yield (5.7 and 6.1 t ha⁻¹ during year 1 and 2, respectively) in wheat. However, these results were also at par with Parthenium hysterophorus and Datura alba extracts in combinations with half the recommended doses of the above mentioned herbicides. The study of microbial activity showed higher amount of mineralizable carbon in D. alba with half the recommended dose of fenoxaprop-p-ethyl treated plots (0.073 g during both the years). The lowest amount of mineralizable carbon (0.035 and 0.030 g during year 1 and 2, respectively) was observed in the control plots. The presence of allelopathic plants in field crops and subsequent mixing in soil by tillage may create problems in crop production. Therefore, further studies are suggested to fully explore all the possible interactions among allelochemicals and herbicides.     

Broadleaved weed control in wide-row soybean (Glycine max) using conventional and glyphosate herbicide programmes

A field study was conducted in 2001 and 2002 at Blackville, SC, to evaluate broadleaved weed control and economics of conventional and glyphosate-containing herbicide programmes in glyphosate-resistant soybean planted in 97-cm-wide rows. Treatments included chlorimuron plus sulfentrazone or chlorimuron plus metribuzin applied pre-emergence followed by post-emergence applications of lactofen or glyphosate 4 wk after soybean emergence (WAE). Other treatments were glyphosate applied 4 WAE, sequential applications of low dose glyphosate applied 2 and 4 WAE, and a non-treated control. Pre-emergence herbicides followed by glyphosate, controlled Ipomoea lacunosa L. 8 WAE. I. hederacea var. integriuscula Gray control with pre-emergence herbicides followed by glyphosate was 100% with similar control from chlorimuron plus sulfentrazone followed by lactofen, whereas control following the single glyphosate application was 84%. Amaranthus palmeri S. Wats. control 9 WAE was 100% following single or sequential glyphosate applications, while control ranged from 76% to 96% with pre-emergence herbicides followed by lactofen. However, early season weed interference when a single application of glyphosate was delayed until 4 WAE reduced soybean yields an average of 389 kg/ha compared to pre-emergence herbicides followed by glyphosate. Based on mean contrasts, pre-emergence herbicides followed by glyphosate had greater gross profit margins than a single glyphosate application alone, but were similar to sequential glyphosate applications. Gross profit margins from pre-emergence herbicides followed by lactofen were not different from glyphosate alone.     

Effect of herbicides and annual weeds on the yield and seed quality of lathyrus (Lathyrus sativus L.)

Field research conducted over six location years has indicated that lathyrus (Lathyrus sativus L.) is a poor competitor with annual weed species. Failure to control annual weeds reduced lathyrus seed yields by 54–95%, depending on the weed species present and their density. Weed competition also reduced thousand-seed weight. Preplant soil-incorporated applications of trifluralin and postemergence applications of sethoxydim controlled wild oat (Avena fatua L.) and green foxtail (Setaria viridis (L.) Beav.). Trifluralin failed to control wild mustard (Sinapis arvensis L.), an important broad-leaved weed in western Canada, but this weed was controlled by both preplant soil-incorporated and postemergence applications of metribuzin. Lathyrus exhibited excellent tolerance to these herbicides, which are currently registered for use on high-acreage crops in Canada.