Weed Technology (WEED TECHNOL )

Publisher: Weed Science Society of America, Weed Science Society of America


Weed Technology publishes original articles about current weed science research and technology, teaching, extension, industry, consulting, and regulation. Weed Technology includes original research on weed biology and control, weed and crop management systems, reports of new weed problems, new technologies for weed management, and special articles emphasizing technology transfer to improve weed control. Journal of the Weed Science Society of America.

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    Weed technology (Online), Weed technology
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Weed Science Society of America

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Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Kochia is a troublesome weed in the western Great Plains and many accessions have evolved resistance to one or more herbicides. Dicamba-resistant soybean is being developed to provide an additional herbicide mechanism of action for POST weed control in soybean. The objective of this study was to evaluate variation in response to dicamba among kochia accessions collected from across Nebraska. Kochia plants were grown in a greenhouse and treated when they were 8 to 12 cm tall. A discriminating experiment with a single dose of 420 g ae ha1 of dicamba was conducted on 67 accessions collected in Nebraska in 2010. Visual injury estimates were recorded at 21 d after treatment (DAT) and accessions were ranked from least to most susceptible. Four accessions representing two of the most and least susceptible accessions from this screening were subjected to dose-response experiments using dicamba. At 28 DAT, visible injury estimates were made and plants were harvested to determine dry weight. An 18-fold difference in dicamba dose was necessary to achieve 90% injury (I90) between the least (accession 11) and most susceptible accessions. Approximately 3,500 g ha1 of dicamba was required in accession 11 to reach a 50% dry weight reduction (GR50). There was less than twofold variation among the three more susceptible accessions for both the I90 and GR90 parameters, suggesting that most kochia accessions will be similarly susceptible to dicamba. At 110 DAT, accession 11 had plants that survived doses of 35,840 g ha1 , and produced seed at doses of 17,420 g ha1 . The identification of one resistant accession among the 67 accessions screened, and the fact that dicamba doses greater than 560 g ha1 were required to achieve GR80 for all accessions suggest that repeated use of dicamba for weed control in fields where kochia is present may quickly result in the evolution of dicamba-resistant kochia populations. Nom
    Weed Technology 04/2014; 28(1):151-162.
  • Weed Technology 01/2014; 28(1):104-110.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Nutsedge control is challenging in commercial vegetable production in the absence of methyl bromide, and therefore, an effective alternative is needed. This study investigated allyl isothiocyanate (ITC) as a methyl bromide alternative for purple nutsedge control under polyethylene-mulch. Greenhouse experiments were conducted to compare the retention of allyl ITC in treated soil (3,000 nmol g�1) under low-density polyethylene (LDPE) and virtually impermeable film (VIF) mulches. Field experiments were conducted to evaluate the effectiveness of allyl ITC (6 rates: 0, 15, 75, 150, 750, 1500 kg ai ha�1) under VIF mulch against purple nutsedge. Additionally, a standard treatment of methyl bromideþchloropicrin (67 : 33%) at 390 kg ai ha�1 under LDPE mulch was included for comparison. In the greenhouse experiment, the predicted half-life of allyl ITC under LDPE and VIF mulch was 0.15 and 0.59 d, respectively. In the field experiment, it was predicted that allyl ITC at 1,240 and 1,097 kg ha�1 under VIF mulch is required to control purple nutsedge shoot and tubers equivalent to methyl bromide þ chloropicrin at 4 wk after treatment (WAT). It is concluded that allyl ITC under VIF mulch would need to be applied at 2.8 to 3.2 times the standard treatment of methyl bromide þ chloropicrin under LDPE mulch for commercially acceptable purple nutsedge control.
    Weed Technology 01/2014; 28.
  • Weed Technology 01/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Crop Protection Online (CPO) is a decision support system, which integrates decision algorithms quantifying the requirement for weed control and a herbicide dose model. CPO was designed to be used by advisors and farmers to optimize the choice of herbicide and dose. The recommendations from CPO for herbicide application in spring barley in Denmark were validated through field experiments targeting three levels of weed control requirement. Satisfactory weed control levels at harvest were achieved by a medium control level requirement generating substantial herbicide reductions (~ 60% measured as the Treatment Frequency Index (TFI)) compared to a high level of required weed control. The observations indicated that the current level of weed control required is robust for a range of weed scenarios. Weed plant numbers 3 wk after spraying indicated that the growth of the weed species were inhibited by the applied doses, but not necessarily killed, and that an adequate level of control was reached later in the season through crop competition.
    Weed Technology 01/2014; 28(1):19-27.
  • Weed Technology 10/2013; 27(4):712-717.
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    ABSTRACT: Weed control in Florida citrus is primarily based on herbicides. Saflufenacil, a POST-applied herbicide is recently registered for broadleaf weed control in citrus. Saflufenacil has very limited grass activity; therefore, it should be tank mixed with graminicides or broad-spectrum herbicides to increase the spectrum of weed control. Greenhouse and field experiments were conducted at two locations (Polk County and Orange County, FL) to evaluate the efficacy and potential antagonism or synergy of saflufenacil and sethoxydim applied alone or tank mixed, and various two- and three-way mixes with glyphosate or pendimethalin. The results suggested that tank mixing saflufenacil and sethoxydim had neither synergistic nor antagonistic effect on broadleaf and grass weed control, respectively. Tank mixing pendimethalin with saflufenacil and sethoxydim improved broadleaf and grass weed control and reduced weed density and biomass, compared with saflufenacil or sethoxydim applied alone or tank mixed at 45 and 60 d after treatment (DAT). Glyphosate tank mixed with saflufenacil and sethoxydim provided > 90 % control of broadleaf and grass weeds at 15 DAT, reduced density ≤ 8 plants m −2 , and reduced biomass < 95 g m −2 at 60 DAT. Glyphosate applied alone was less effective than it was when tank mixed with saflufenacil and sethoxydim or pendimethalin for broadleaf and grass weed control, indicating an additive effect of tank mixture on glyphosate efficacy. It is concluded that saflufenacil can be tank mixed with sethoxydim for control of broadleaf and grass weeds without antagonism on the efficacy of either herbicide; however, tank mixing saflufenacil and sethoxydim with glyphosate or pendimethalin provided long-term, broad-spectrum weed control in Florida citrus. El control de malezas en cítricos en Florida está basado principalmente en herbicidas. Saflufenacil, un herbicida aplicado POST, fue registrado recientemente para el control de malezas de hoja ancha en cítricos. Saflufenacil tiene actividad muy limitada sobre gramíneas; por lo que debe ser mezclado en tanque con graminicidas o herbicidas de amplio espectro para incrementar el espectro de control de malezas. Se realizaron estudios de invernadero y de campo en dos localidades (condados Polk y Orange en Florida) para evaluar la eficacia y el antagonismo o sinergismo potencial de saflufenacil y sethoxydim aplicados solos o en mezcla en tanque, y varias mezclas en dos y tres formas con glyphosate o pendimethalin. Los resultados sugirieron que mezclar en tanque saflufenacil y sethoxydim no tuvo efectos sinérgicos ni antagónicos en el control de malezas de hoja ancha o gramíneas, respectivamente. El mezclar en tanque pendimethalin con saflufenacil y sethoxydim mejoró el control de malezas de hoja ancha y gramíneas y redujo la densidad y biomasa de malezas a 45 y 60 días después del tratamiento (DAT), en comparación con saflufenacil o sethoxydim aplicados individualmente o en mezcla en tanque. Glyphosate mezclado en tanque con saflufenacil y sethoxydim brindó >90% de control de malezas de hoja ancha y gramíneas a 15 DAT, redujo la densidad ≤8 plantas m −2 y redujo la biomasa <95 g m −2 a 60 DAT. Glyphosate aplicado solo fue menos efectivo que cuando se aplicó en mezcla en tanque con saflufenacil y sethoxydim o pendimethalin para el control de malezas de hoja ancha y gramíneas indicando un efecto aditivo de la mezcla en tanque sobre la eficacia de glyphosate. Se concluye que saflufenacil puede ser mezclado en tanque con sethoxydim para el control de malezas de hoja ancha y gramíneas sin causar antagonismo sobre la eficacia de ninguno de estos herbicidas. Sin embargo, el mezclar en tanque saflufenacil y sethoxydim con glyphosate o pendimethalin brindó un control de amplio espectro de malezas de larga duración en cítricos en Florida.
    Weed Technology 01/2013; 27(1):129-137.
  • [Show abstract] [Hide abstract]
    ABSTRACT: With growing agricultural demands from both conventional and organic systems comes the need for sustainable practices to ensure long-term productivity. Implementation of reduced- or no-till practices offers a number of environmental benefits for agricultural land and maintains adequate yield for current and future production. Concerns over satisfactory pest control options, particularly weed control, have contributed to the slow adoption of conservation practices in many areas. To identify effective alternative weed management options for use in conservation systems, research in the Southeast has continued to evaluate the use of cover crops in conjunction with reduced-tillage practices. A number of cover crop species, including cereal grains, legumes, and Brassicaceae species, that have potential to suppress weeds through direct crop interference or allelopathic potential have been investigated. Many recent research projects in the Midsouth and southeastern United States have assessed the success of cover crops in reduced-tillage row crop settings with promising outcomes in some systems. However, continued research is necessary to identify appropriate cover crop and tillage systems for use in other agricultural settings, such as vegetable crops and organic production systems. Con el incremento en la demanda de productos agrícolas tanto de sistemas convencionales como orgánicos, viene la necesidad de prácticas sostenibles que aseguren la productividad a largo plazo. La implementación de prácticas de labranza reducida o cero ofrece un número de beneficios ambientales para la tierra agrícola y mantiene rendimientos adecuados para la producción actual y futura. La preocupación con respecto al control satisfactorio de plagas, particularmente de malezas, ha contribuido a la lenta adopción de prácticas de conservación en muchas áreas. Con el objectivo de identificar opciones alternativas para el manejo de malezas, las investigaciones en el Sureste han continuado para evaluar el uso de cultivos de cobertura en combinación con prácticas de labranza reducida. Se han investigado varias especies como cultivos de cobertura, incluyendo cereales, leguminosas y especies Brassicaceae, que tienen el potencial de suprimir malezas mediante la interferencia directa del cultivo o por su potencial alelopático. Muchos proyectos de investigación recientes en el Sur medio y en el Sureste de los Estados Unidos han evaluado el éxito de cultivos de cobertura en cultivos extensivos y bajo labranza reducida con resultados promisorios en varios sistemas. Sin embargo, se necesita que la investigación continúe para identificar cultivos de cobertura apropiados y sistemas de labranza para el uso en otros sistemas agrícolas, tales como vegetales y sistemas de producción orgánica.
    Weed Technology 01/2013; 27(1):212-217.
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    ABSTRACT: Vapor movement of synthetic auxin herbicides can injure desirable plants outside the treatment zone. Vapor movement of the synthetic auxin herbicides aminocyclopyrachlor and aminocyclopyrachlor methyl was compared with that of the relatively volatile herbicide dicamba and the low volatile herbicide aminopyralid with a soybean bioassay under greenhouse and field conditions. Soybean is very sensitive to these active ingredients. Under greenhouse conditions, 82 (61 to 104) mg ae ha −1 of aminocyclopyrachlor, 26 (18 to 33) mg ae ha −1 of aminocyclopyrachlor methyl, 82 (69 to 95) mg ae ha −1 of aminopyralid, and 61 (47 to 75) mg ae ha −1 of dicamba produced an estimated 25% visual soybean phytotoxicity response when soybean was treated POST at the V3 growth stage (GR 25 [95% confidence interval]). In field studies, aminocyclopyrachlor, aminocyclopyrachlor methyl, and aminopyralid were applied at 70 g ae ha −1 and dicamba was applied at 560 g ae ha −1 (labeled application rates) to soybean at the V3 growth stage. All herbicides were applied within an enclosed chamber (3 m by 3 m by 1 m) to mitigate movement of spray droplets. The enclosures were removed shortly after spray application and soybean response immediately surrounding the treated area was recorded in each of eight directions approximately 10 d after treatment. On the basis of bioassay responses, relative amount of vapor movement was dicamba > aminocyclopyrachlor methyl > aminopyralid ≈ aminocyclopyrachlor. Vapor movement of aminocyclopyrachlor was very low indicating that the risk of phytotoxic response of sensitive plants due to volatility of aminocyclopyrachlor is negligible. El movimiento de vapores de herbicidas auxinas sintéticas puede dañar plantas deseables fuera de la zona de tratamiento. El movimiento de vapores de los herbicidas auxinas sintéticas aminocyclopyrachlor y aminocyclopyrachlor methyl fue comparado con el del herbicida relativamente volátil dicamba y del herbicida de baja volatilidad aminopyralid con un bioensayo con soya bajo condiciones de invernadero y de campo. La soya es muy sensible a estos ingredientes activos. Bajo condiciones de invernadero, 82 (61 a 104) mg ae ha −1 de aminocyclopyrachlor, 26 (18 a 33) mg ae ha −1 de aminocyclopyrachlor methyl, 82 (69 a 95) mg ae ha −1 de aminopyralid, y 61 (47 a 75) mg ae ha −1 de dicamba produjeron un estimado de 25% de respuesta de fitotoxicidad visual en la soya cuando la soya fue tratada POST en el estado de desarrollo V3 (GR 25 [95% intervalo de confianza]). En los estudios de campo, aminocyclopyrachlor, aminocyclopyrachlor methyl, y aminopyralid fueron aplicados a 70 g ha −1 y dicamba fue aplicado a 560 g ha −1 (dosis de aplicación según la etiqueta) a soya en el estado de desarrollo V3. Todos los herbicidas fueron aplicados dentro de una cubierta cerrada (3 m por 3 m por 1 m) par mitigar el movimiento de gotas de aspersión. Las cubiertas fueron removidas poco después de la aplicación y la respuesta de la soya localizada inmediatamente alrededor del área tratada fue registrada en cada una de las ocho direcciones aproximadamente 10 días después del tratamiento. Con base en las respuestas de los bioensayos, el movimiento relativo del vapor fue dicamba > aminocyclopyrachlor methyl > aminopyralid ≈ aminocyclopyrachlor. El movimiento del vapor de aminocyclopyrachlor fue muy bajo, indicando así que el riesgo de la respuesta de fitotoxicidad de plantas sensibles debido a la volatilidad de aminocyclopyrachlor es insignificante.
    Weed Technology 01/2013; 27(1):143-155.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Noninversion tillage with tine- or disc-based cultivations prior to crop establishment is the most common way of reducing tillage for arable cropping systems with small grain cereals, oilseed rape, and maize in Europe. However, new regulations on pesticide use might hinder further expansion of reduced-tillage systems. European agriculture is asked to become less dependent on pesticides and promote crop protection programs based on integrated pest management (IPM) principles. Conventional noninversion tillage systems rely entirely on the availability of glyphosate products, and herbicide consumption is mostly higher compared to plow-based cropping systems. Annual grass weeds and catchweed bedstraw often constitute the principal weed problems in noninversion tillage systems, and crop rotations concurrently have very high proportions of winter cereals. There is a need to redesign cropping systems to allow for more diversification of the crop rotations to combat these weed problems with less herbicide input. Cover crops, stubble management strategies, and tactics that strengthen crop growth relative to weed growth are also seen as important components in future IPM systems, but their impact in noninversion tillage systems needs validation. Direct mechanical weed control methods based on rotating weeding devices such as rotary hoes could become useful in reduced-tillage systems where more crop residues and less workable soils are more prevalent, but further development is needed for effective application. Owing to the frequent use of glyphosate in reduced-tillage systems, perennial weeds are not particularly problematic. However, results from organic cropping systems clearly reveal that desisting from glyphosate use inevitably leads to more problems with perennials, which need to be addressed in future research. El cultivar sin inversión del suelo usando discos o picos, antes del establecimiento del cultivo, es la forma más común de reducir la labranza en sistemas de cultivos arables que incluyen cereales, colza y maíz en Europa. Sin embargo, nuevas regulaciones sobre el uso de plaguicidas podrían afectar la expansión de los sistemas de labranza reducida. La agricultura europea ha sido llamada a ser menos dependiente de los plaguicidas y a promover programas de protección de cultivos basados en los principios de manejo integrado de plagas (IPM). Los sistemas de labranza convencional sin inversión del suelo dependen totalmente de la disponibilidad de productos con glyphosate, y el consumo de herbicidas es mayoritariamente superior al compararse con sistemas de cultivo basados en el uso de arado. Malezas como zacates anuales y Galium aparine frecuentemente constituyen el principal problema de malezas en sistemas de labranza sin inversión del suelo y rotaciones de cultivos que además tienen proporciones muy altas de cereales de invierno. Existe la necesidad de rediseñar los sistemas de cultivos para permitir una mayor diversificación de las rotaciones de cultivos para así combatir estos problemas de malezas con un uso menor de herbicidas. Cultivos de cobertura, sistemas de manejo con residuos de cultivos, y tácticas que refuercen el crecimiento del cultivo en relación con el crecimiento de las malezas son también vistos como componentes importantes en los sistema IPM futuros, pero su impacto en los sistemas de labranza sin inversión del suelo necesita validación. Los métodos de control mecánico de malezas directo basados en implementos rotativos de deshierba, tales como azadones rotativos, han sido útiles en sistemas de labranza reducida donde la presencia de más residuos de cultivos y suelos menos trabajables son prevalentes, pero un mayor desarrollo de estos métodos es necesario para su aplicación efectiva. Debido al uso frecuente de glyphosate en sistemas de labranza reducida, las malezas perennes no son particularmente problemáticas. Sin embargo, resultados en sistemas de producción orgánicos han revelado claramente que el desistir del uso de glyphosate lleva inevitablemente a más problemas con malezas perennes, lo que necesita ser incluido en investigaciones futuras.
    Weed Technology 01/2013; 27(1):231-240.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Nonsynthetic herbicides offer a potentially useful addition to the suite of weed management tools available to organic growers, but limited information is available to guide the optimal use of these products. The objectives of this research were to (1) evaluate the efficacy of clove oil—and vinegar-based herbicides on weeds across multiple states, and (2) assess the potential role of temperature, relative humidity (RH), and cloud cover in explaining inter-state variations in results. From 2006 to 2008, a total of 20 field trials were conducted in seven states using an identical protocol. Seeds of brown mustard were sown and herbicides applied to both mustard and emerged weeds when mustard reached the three- to four-leaf stage. Treatments included clove oil at 2.5, 5, 7.5, and 10% v/v concentrations at 54 L ha −1 , and vinegar at 5, 10, 15, and 20% v/v concentrations at 107 L ha −1 . Results varied widely across trials. In general, concentrations of at least 7.5% for clove oil and 15% for vinegar were needed for adequate control of mustard. Both products were more effective at suppressing mustard than Amaranthus spp. or common lambsquarters. Poor control was observed for annual grasses. No significant effects of cloud cover on the efficacy of either product were detected. In contrast, RH was positively correlated with control of brown mustard by both clove oil and vinegar with improved control at higher RH. Temperature had no detectable effect on the efficacy of clove oil, but higher temperatures improved control of brown mustard by vinegar. Herbicidas no-sintéticos ofrecen potencialmente una adición útil a la variedad de herramientas para el manejo de malezas, disponible para productores orgánicos. Sin embargo, hay poca información disponible para guiar el uso óptimo de estos productos. Los objectivos de esta investigación fueron (1) evaluar, en diferentes estados, la eficacia de herbicidas a base de aceite de trébol y de vinagre sobre malezas, y (2) evaluar el papel potencial de la temperatura, humedad relativa (RH), y la cobertura nubosa para explicar variaciones inter-estatales en los resultados. De 2006 a 2008, un total de 20 experimentos de campo fueron realizados en siete estados usando un protocolo idéntico. Semillas de mostaza (Brassica juncea) fueron sembradas y los herbicidas aplicados a la mostaza y malezas emergidas cuando la mostaza alcanzó el estado de desarrollo de tres a cuatro hojas. Los tratamientos incluyeron aceite de trébol a concentraciones de 2.5, 5, 7.5 y 10% v/v a 54 L ha −1 , y vinagre a concentraciones de 5, 10, 15 y 20% v/v a 107 L ha −1 . Los resultados variaron ampliamente entre experimentos. En general, concentraciones de al menos 7.5% para el aceite de trébol y 15% para el vinagre fueron necesarias para el control adecuado de la mostaza. Ambos productos fueron más efectivos para suprimir la mostaza que Amaranthus spp. o Chenopodium album. Se observó un control pobre de gramíneas anuales. No se detectaron efectos significativos de la cobertura nubosa sobre la eficacia de ninguno de los productos. En cambio, la RH estuvo positivamente correlacionada con el control de la mostaza por el aceite de trébol y el vinagre con un mejor control a RH más altas. La temperatura no tuvo efectos detectables sobre la eficacia del aceite de trébol, pero las temperaturas altas mejoraron el control de la mostaza con vinagre.
    Weed Technology 01/2013; 27(1):156-164.
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    ABSTRACT: Clovers are commonly included as utility plants within mixed grass swards, such as pastures and roadside right-of-ways. As such, they provide supplemental nitrogen, quality forage, and insect habitat. Yet weed control within mixed swards is often hampered by the lack of selective herbicides that are tolerated by clovers. Differential tolerance of legumes to common row-crop and pasture herbicides has previously been reported, yet little information is available that is specific to clover species. Herbicide injury of clover is often inconsistent, hypothetically due to differential species tolerance. Field and greenhouse experiments were conducted with the objective of testing differential tolerance amongst four clover species. Our experiments suggest varying tolerances amongst clover species and common broadleaf herbicides. Only imazaquin control differed due to species; however, treatment by clover interactions were further demonstrated due to variable reductions in clover height. Imazaquin, 2,4-D, 2,4-DB, and triclopyr height reductions differed due to clover species. Differential clover response to herbicide treatment should be an important consideration when managing mixed grass—clover swards and should be accounted for in future research. On a more practical level, our experiments demonstrate a range of herbicides that effectively control clover species, including atrazine, dicamba, clopyralid, 2,4-D, triclopyr, metsulfuron, and trifloxysulfuron. However, results suggest that 2,4-DB, imazethapyr, and bentazon are candidate herbicides for weed control in scenarios in which clover is a desirable crop. Los tréboles son comúnmente incluidos como plantas útiles dentro de zonas con coberturas mixtas de zacates, tales como pastizales y bordes de caminos. De tal forma, que brinden nitrógeno suplementario, calidad de forraje y hábitat para insectos. Sin embargo, dentro de esas zonas de cobertura mixta, el control de malezas se ve frecuentemente obstaculizado por la ausencia de herbicidas selectivos que sean tolerados por los tréboles. La tolerancia diferencial de leguminosas a herbicidas para cultivos extensivos y pasturas ha sido reportada anteriormente, aunque hay poca información disponible que sea específica para especies de trébol. El daño causado por los herbicidas es usualmente inconsistente, hipotéticamente debido a las diferencias en tolerancia entre especies. Se realizaron experimentos de campo y de invernadero con el objetivo de evaluar la tolerancia diferencial entre cuatro especies de trébol. Nuestros experimentos sugieren que existe variación entre especies de trébol en la tolerancia a herbicidas de hoja ancha comunes. Solamente el control con imazaquin difirió debido a las especies, aunque interacciones entre tratamiento y especie de trébol fueron demostradas debido a reducciones variables en la altura del trébol. Las reducciones en altura, producto del efecto de imazaquin, 2,4-D, 2,4-DB y triclopyr, variaron según la especie de trébol. La respuesta diferencial de los tréboles a los tratamientos con herbicidas debería ser una consideración importante cuando se manejan áreas con coberturas mixtas de zacates y tréboles y debería ser incluida en investigaciones futuras. A un nivel más práctico, nuestros experimentos muestran un rango de herbicidas que efectivamente controlan especies de trébol, incluyendo atrazine, dicamba, clopyralid, 2,4-D, triclopyr, metsulfuron, and trifloxysulfuron. Sin embargo, los resultados sugieren que 2,4-DB, imazethapyr y bentazon son herbicidas candidatos para el control de malezas en escenarios en los cuales el trébol es un cultivo deseable.
    Weed Technology 01/2013; 27(1):123-128.
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    ABSTRACT: Integrated weed management (IWM) can be defined as a holistic approach to weed management that integrates different methods of weed control to provide the crop with an advantage over weeds. It is practiced globally at varying levels of adoption from farm to farm. IWM has the potential to restrict weed populations to manageable levels, reduce the environmental impact of individual weed management practices, increase cropping system sustainability, and reduce selection pressure for weed resistance to herbicides. There is some debate as to whether simple herbicidal weed control programs have now shifted to more diverse IWM cropping systems. Given the rapid evolution and spread of herbicide-resistant weeds and their negative consequences, one might predict that IWM research would currently be a prominent activity among weed scientists. Here we examine the level of research activity dedicated to weed control techniques and the assemblage of IWM techniques in cropping systems as evidenced by scientific paper publications from 1995 to June 1, 2012. Authors from the United States have published more weed and IWM-related articles than authors from any other country. When IWM articles were weighted as a proportion of country population, arable land, or crop production, authors from Switzerland, the Netherlands, New Zealand, Australia, and Canada were most prominent. Considerable evidence exists that research on nonherbicidal weed management strategies as well as strategies that integrate other weed management systems with herbicide use has increased. However, articles published on chemical control still eclipse any other weed management method. The latter emphasis continues to retard the development of weed science as a balanced discipline. El manejo integrado de malezas (IWM) puede ser definido como un enfoque holístico del manejo de malezas que integra diferentes métodos de control para brindar al cultivo una ventaja sobre las malezas. Esto es practicado globalmente con niveles de adopción que varían de finca a finca. El IWM tiene el potencial de restringir las poblaciones de malezas a niveles manejables, reducir el impacto ambiental de prácticas individuales de manejo de malezas, incrementar la sostenibilidad de los sistemas de cultivos y reducir la presión de selección sobre la resistencia a herbicidas de las malezas. Existe cierto debate acerca de si programas de control de malezas basados simplemente en herbicidas, ahora se han convertido a sistemas de cultivos con IWM más diversos. Dada la rápida evolución y dispersión de malezas resistentes a herbicidas y sus consecuencias negativas, uno podría predecir que la investigación en IWM sería actualmente una actividad prominente entre científicos de malezas. Aquí examinamos el nivel de actividad investigativa dedicada a técnicas de control de malezas y al ensamblaje de técnicas de IWM en sistemas de cultivos, usando como evidencia la publicación de artículos científicos desde 1995 al 1 de Junio, 2012. Autores de los Estados Unidos han publicado más artículos relacionados a malezas y a IWM que autores de cualquier otro país. Cuando se ajustó el peso de los artículos de IWM como proporción de la población del país, tierras arables o producción de cultivos, autores de Suiza, Holanda, Nueva Zelanda, Australia y Canadá fueron los más prominentes. Existe considerable evidencia de que ha incrementado la investigación sobre estrategias no-herbicidas de manejo de malezas y también sobre las estrategias que integran otros sistemas de manejo de malezas con el uso de herbicidas. Sin embargo, los artículos publicados sobre control químico todavía eclipsan cualquier otro método de manejo de malezas. Este último énfasis continúa retrasando el desarrollo de la ciencia de malezas como una disciplina balanceada.
    Weed Technology 01/2013; 27(1):1-11.
  • Weed Technology 01/2013; 27(2):378-388.
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    ABSTRACT: In fall 2011, cotton and soybean consultants from Arkansas, Louisiana, Mississippi, and Tennessee were surveyed through direct mail and on-farm visits, and rice consultants from Arkansas and Mississippi were surveyed through direct mail to assess the importance and level of implementation of herbicide resistance best management practices (HR-BMPs) for herbicide-resistant weeds. Proper herbicide timing, clean start with no weeds at planting, application of multiple effective herbicide modes of action, use of full labeled herbicide rates, and prevention of crop weed seed production with importance rating of >4.6 out of 5.0 were perceived as the most important HR-BMPs in all crops. Purchase of certified rice seed was on 90% of scouted hectares. In contrast, least important HR-BMPs as perceived by consultants with importance ratings of <4.0 in cotton, <3.7 in rice, and <3.8 in soybean were cultural practices such as manual removal of weeds; tillage including disking, cultivation, or deep tillage; narrow (<50 cm)-row crops, cover crops, and altered planting dates. Narrow crop rows and cover crops in cotton; altered planting dates in cotton and soybean; and cleaning of farm equipment and manual weeding in rice and soybean is currently employed on <20% of scouted hectares. Extra costs, time constraints, adverse weather conditions, lack of labor and equipment, profitability, herbicide-related concerns, and complacency were perceived as key obstacles for adoption of most HR-BMPs. With limited adoption of most cultural practices that reduce risks of herbicide-resistant weeds, there are opportunities to educate growers concerning the proactive need and long-term benefits of adopting HR-BMPs to ensure sustainable weed management and profitable crop production.
    Weed Technology 01/2013;
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    ABSTRACT: Greenhouse and field experiments were conducted to determine whether PRE-applied ethofumesate increased POST spray retention and weed control with glyphosate. In greenhouse studies, ethofumesate was applied PRE at rates from 0 to 224 g ai ha −1 followed by POST treatment with either water or glyphosate (840 g ae ha −1 ) to which a red dye had been added. Plants were immediately washed and spray retention determined spectrophotometrically. Common lambsquarters retained more glyphosate solution compared to water, regardless of PRE ethofumesate rate. Increasing the rate of PRE ethofumesate increased the POST spray retention of both water and glyphosate. PRE application of ethofumesate increased POST spray retention of water by 114% and glyphosate solution by 18% compared to no ethofumesate treatment as determined by nonlinear regression. Ethofumesate rates of 90 g ha −1 increased POST spray retention to at least 95% of the total observed response. In field studies, common lambsquarters, redroot pigweed, and hairy nightshade densities were all reduced by ethofumesate, although the duration of ethofumesate effect varied by species and ethofumesate application timing. PRE ethofumesate had no significant effect on hairy nightshade density until after POST glyphosate was applied, whereas common lambsquarters densities were most affected by PRE ethofumesate early in the season. Late-season redroot pigweed density was reduced by ethofumesate regardless of application timing. Se realizaron experimentos de campo y de invernadero para determinar si ethofumesate aplicado PRE incrementó la retención de aplicaciones de glyphosate POST y el control de malezas. En los estudios de invernadero, ethofumesate fue aplicado PRE a dosis de 0 a 224 g ha −1 seguidos de tratamientos POST con agua o glyphosate (840 g ae ha −1 ) a los cuales se les había agregado un colorante rojo. Las plantas fueron lavadas inmediatamente y la retención fue determinada espectrofotométricamente. Chenopodium album retuvo más glyphosate al compararse con agua, sin importar la dosis PRE de ethofumesate. Al incrementarse la dosis PRE de ethofumesate se aumentó la retención de las aplicaciones POST de agua y glyphosate. La aplicación PRE de ethofumesate incrementó la retención de agua POST en 114% y la de glyphosate en 18% en comparación al tratamiento sin ethofumesate, como se determinó usando regresiones no lineales. Dosis menores a 90 g ha −1 de ethofumesate incrementaron la retención de aplicaciones POST al 95% del total de respuestas observadas. En los estudios de campo, las densidades de C. album, Amaranthus retroflexus y Solanum sarrachoides fueron todas reducidas por ethofumesate, aunque la duración del efecto de ethofumesate varió según la especie y el momento de aplicación de ethofumesate. Ethofumesate PRE no tuvo ningún efecto en la densidad de S. sarrachoides hasta después de que se aplicó glyphosate POST, mientras que las densidades de C. album se vieron más afectadas por ethofumesate PRE, temprano en la temporada. La densidad de A. retroflexus, tarde en la temporada, fue reducida por ethofumesate sin importar el momento de aplicación.
    Weed Technology 01/2013; 27(1):47-53.

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