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David E Johnson - One of the best experts on this subject based on the ideXlab platform.
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differences in responses to flooding by germinating seeds of two contrasting rice cultivars and two species of economically important grass weeds
Aob Plants, 2014Co-Authors: Lucy P Estioko, Berta Miro, Aurora M Baltazar, Florinia E Merca, Abdelbagi M Ismail, David E JohnsonAbstract:Crop productivity is largely affected by abiotic factors such as flooding and by biotic factors such as weeds. Although flooding after direct seeding of rice helps suppress weeds, it also can adversely affects germination and growth of rice, resulting in poor crop establishment. Barnyard grasses (Echinochloa spp.) are among the most widespread weeds affecting rice, especially under direct seeding. The present work aimed to establish effective management options to control these weeds. We assessed the effects of variable depths and time of submergence on germination, seedling growth and carbohydrate metabolism of (i) two cultivars of rice known to differ in their tolerance to flooding during germination and (ii) two barnyard grasses (Echinochloa Colona and E. crus-galli) that commonly infest rice fields. Flooding barnyard grasses with 100-mm-deep water immediately after seeding was effective in suppressing germination and growth. Echinochloa Colona showed greater reductions in emergence, shoot and root growth than E. crus-galli. Delaying flooding for 2 or 4 days was less injurious to both species. Echinochloa Colona was also more susceptible to flooding than the flood-sensitive rice cultivar 'IR42'. The activity of alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) in rice seedlings was increased by flooding after sowing but with greater increases in 'Khao Hlan On' compared with 'IR42'. The activity of ADH and PDC was enhanced to a similar extent in both barnyard grasses. Under aerobic conditions, the activity of ADH and PDC in the two barnyard grasses was downregulated, which might contribute to their inherently faster growth compared with rice. Aldehyde dehydrogenase activity was significantly enhanced in flood-tolerant 'Khao Hlan On' and E. crus-galli, but did not increase in flood-sensitive E. Colona and 'IR42', implying a greater ability of the flood-tolerant types to detoxify acetaldehyde generated during anaerobic fermentation. Confirmation of this hypothesis is now being sought.
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implications of narrow crop row spacing and delayed Echinochloa Colona and Echinochloa crus galli emergence for weed growth and crop yield loss in aerobic rice
Field Crops Research, 2010Co-Authors: Bhagirath S Chauhan, David E JohnsonAbstract:Field experiments were conducted in 2008 and 2009 to determine growth and seed production of Echinochloa Colona and Echinochloa crus-galli emerging at five intervals (0, 15, 30, 45, and 60 days after rice emergence, DARE) in aerobic rice seeded at 20- and 30-cm row spacing. Plant height of these two weed species was not influenced by the crop row, but it was influenced by the weed emergence time. Weeds of either species emerging until 30 DARE had greater biomass and more seeds under wide rows than under narrow rows, but row spacing had no effect on biomass and seeds of plants emerging later. In both crop row spacing treatments, delay in weed emergence until 45 DARE significantly reduced weed biomass. E. Colona and E. crus-galli plants that emerged 60 DARE produced only 3 seeds plant-1 in 30-cm rows, whereas no seed was produced by these plants in 20-cm rows. Fitting a single linear function to the combined data for rows and weed emergence time gave a strong positive linear relationship between shoot biomass (g plant-1) and seed production (number plant-1) of these species, accounting for 94% and 93% variation in E. Colona and E. crus-galli, respectively. These relationships can be used as a predictor of seed production in these species. Regardless of the weed species and weed emergence date, rice grain yields were greater in narrow rows than in wider rows. In the case of both weed species, rice grain yield improved significantly with each delay in weed emergence up to 45 DARE. The results of this study suggest that narrowing row spacing and controlling early weeds led to decreased weed growth and seed production, and increased grain yield in aerobic rice. Narrow crop row spacing and early weed control could be important components of integrated weed management strategies in aerobic rice.
Ramírez Suárez, Javier Guillermo - One of the best experts on this subject based on the ideXlab platform.
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Dinámica poblacional de malezas del cultivo de arroz en las zonas centro, meseta y norte del Departamento del Tolima
2014Co-Authors: Ramírez Suárez, Javier GuillermoAbstract:La presencia de malezas en lotes arroceros es un problema agronómico generalizado en todos los campos de cultivo del mundo. Entre los meses de Julio de 2012 y Febrero de 2013, se realizó el presente trabajo de investigación con el objetivo de establecer el comportamiento poblacional de malezas de cultivos de arroz ubicados en el departamento del Tolima (Colombia). Se muestreó la comunidad de malezas de lotes comerciales ubicados en las zonas Centro, Meseta y Norte del departamento. Los muestreos de campo se hicieron en una muestra de 96 hectáreas de cultivo las cuales fueron distribuidas de manera proporcional en cada zona de acuerdo al área sembrada. Para las evaluaciones se utilizó un cuadro de muestreo de 20 x 20 centímetros. Éstas se hicieron antes y después de cada aplicación post-emergente así: la primera entre los 7 y 22 días después de siembra (antes de la aplicación post-emergente temprana), la segunda entre los 22 y 35 d.d.s (después de la aplicación post-emergente temprana), la tercera entre 37 y 52 d.d.s (después de la aplicación post-emergente media) y la cuarta entre 52 y 65 d.d.s (al final de las aplicaciones de control). En cada muestreo se identificaron las especies encontradas y se evaluaron las variables frecuencia, densidad, cobertura y porcentaje de control de malezas. El reconocimiento y estudio de la estructura de la comunidad de malezas en las tres zonas, mediante las variables mencionadas permitió la obtención de índices de diversidad, similitud y valor de importancia. El índice de valor de importancia (IVI) mostró que las cinco especies más importantes en el departamento son: Echinochloa Colona (L.) Link, Digitaria ciliaris (Retz.) Koel, Cyperus iria (L.), Ischaemum rugosum Salisb y Murdannia nudiflora (L.) Brenan. Para la zona Centro son: Rottboellia conchinchinensis (Lour.) W.D. Clayton, E. Colona, C. iria, I. rugosum y Leptochloa scabra Nees. En la Meseta son: C. iria, E. Colona, Digitaria bicornis (Lam.) Roemer & J.A. Schultes ex Loud, Eclipta alba (L.) Hassk e I. rugosum. Para la zona Norte: D. ciliaris, E. Colona, C. iria, M. nudiflora y Paspalum boscianum Flueggé. Los índices de Shannon-Wiener y Simpson mostraron mayor diversidad en la Meseta. Los índices de Jaccard y Sorensen mostraron que existe disimilitud en la estructura de la comunidad de las zonas evaluadas. La eficiencia de los herbicidas aplicados en post-emergencia fue evaluada midiendo la densidad de las poblaciones y evaluando el porcentaje de control de malezas. El porcentaje de control de la primera aplicación post-emergente en términos reducción de individuos fue de 29% en la zona Centro, 34% en Meseta y 52% en Norte. El porcentaje de control de los herbicidas de la segunda aplicación post-emergente en disminución de densidad de malezas fue de 7%, 5% y 22% en las zonas Centro, Meseta y Norte respectivamente. Dichos niveles de control suprimen las poblaciones de malezas y evitan un efecto negativo mayor sobre el cultivo. La zona Norte exhibe mayor porcentaje de control.Abstract. Weeds are a severe problem in all rice’s crops around the world. The present study was made between July 2012 and February 2013 with the aimed to study population behavior of weeds associated with the cultivation in three areas of Tolima (Colombia).This study was carried out by sampling weed community of crops located in areas Centro, Meseta y Norte. Weed evaluations in the fields occurred in 96 hectares distributed according to area planted in each zone. This procedure was made using squares (20 x 20 cm). These evaluations were made before and after each one of post-emergence herbicide applications like this: the first one between 7 and 22 days after sowing (before early post-emergence application), the second one between 22 and 35 d.a.s (after early post-emergence application), the third one between 37 and 52 d.a.s (after medium post-emergence application) and the fourth one between 52 and 65 d.a.s (at the end of control applications). In each sampling were identified each one of weeds and were evaluated variables like frequency, density, coverage and percent control of weeds. Recognition and study of weed community structure in three areas through these variables allowed obtaining diversity index, coefficients of similarity and importance value index. The importance value index showed that the five most important weeds in the department are: Echinochloa Colona, Digitaria ciliaris, Cyperus iria, Ischaemum rugosum and Murdannia nudiflora. For the Central región are: Rottboellia cochinchinensis, Echinochloa Colona, Cyperus iria, Ischaemum rugosum and Leptochloa scabra. In the Meseta are: Cyperus iria, Echinochloa Colona, Digitaria bicornis, Eclipta alba and Ischaemum rugosum. To the Norte: Digitaria ciliaris, Echinochloa Colona, Cyperus iria, Murdannia nudiflora and Paspalum boscianum. Shannon-Wiener index and Simpson index show greater diversity in the Meseta. The Jaccard and Sorensen index showed that there is dissimilarity in the community structure of the areas evaluated. Efficiency of these herbicides was evaluated through density of the sampled species and percent of weed control. First post-emergence applications reduced weed density in 29% for Centro zone, 34% in Meseta and 52% in Norte. Percent of weed control of this application in Centro zone was 57%, 63% in Meseta and 67% in Norte. Second post-emergence applications reduced in 7%, 5% and 22% weed density for Centro, Meseta and Norte zones, respectively. Percent of weed control of this application for Centro zone was 61%, 53% in Meseta and 64% in Norte. These control rates suppress weeds’ populations sufficiently and avoid a greater negative effect. Norte zone show a greater reduction for weed density and a bigger percent of control
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Dinámica poblacional de malezas del cultivo de arroz en las zonas centro, meseta y norte del Departamento del Tolima
Universidad Nacional de Colombia - Sede Bogotá, 2014Co-Authors: Ramírez Suárez, Javier GuillermoAbstract:La presencia de malezas en lotes arroceros es un problema agronómico generalizado en todos los campos de cultivo del mundo. Entre los meses de Julio de 2012 y Febrero de 2013, se realizó el presente trabajo de investigación con el objetivo de establecer el comportamiento poblacional de malezas de cultivos de arroz ubicados en el departamento del Tolima (Colombia). Se muestreó la comunidad de malezas de lotes comerciales ubicados en las zonas Centro, Meseta y Norte del departamento. Los muestreos de campo se hicieron en una muestra de 96 hectáreas de cultivo las cuales fueron distribuidas de manera proporcional en cada zona de acuerdo al área sembrada. Para las evaluaciones se utilizó un cuadro de muestreo de 20 x 20 centímetros. Éstas se hicieron antes y después de cada aplicación post-emergente así: la primera entre los 7 y 22 días después de siembra (antes de la aplicación post-emergente temprana), la segunda entre los 22 y 35 d.d.s (después de la aplicación post-emergente temprana), la tercera entre 37 y 52 d.d.s (después de la aplicación post-emergente media) y la cuarta entre 52 y 65 d.d.s (al final de las aplicaciones de control). En cada muestreo se identificaron las especies encontradas y se evaluaron las variables frecuencia, densidad, cobertura y porcentaje de control de malezas. El reconocimiento y estudio de la estructura de la comunidad de malezas en las tres zonas, mediante las variables mencionadas permitió la obtención de índices de diversidad, similitud y valor de importancia. El índice de valor de importancia (IVI) mostró que las cinco especies más importantes en el departamento son: Echinochloa Colona (L.) Link, Digitaria ciliaris (Retz.) Koel, Cyperus iria (L.), Ischaemum rugosum Salisb y Murdannia nudiflora (L.) Brenan. Para la zona Centro son: Rottboellia conchinchinensis (Lour.) W.D. Clayton, E. Colona, C. iria, I. rugosum y Leptochloa scabra Nees. En la Meseta son: C. iria, E. Colona, Digitaria bicornis (Lam.) Roemer and J.A. Schultes ex Loud, Eclipta alba (L.) Hassk e I. rugosum. Para la zona Norte: D. ciliaris, E. Colona, C. iria, M. nudiflora y Paspalum boscianum Flueggé. Los índices de Shannon-Wiener y Simpson mostraron mayor diversidad en la Meseta. Los índices de Jaccard y Sorensen mostraron que existe disimilitud en la estructura de la comunidad de las zonas evaluadas. La eficiencia de los herbicidas aplicados en post-emergencia fue evaluada midiendo la densidad de las poblaciones y evaluando el porcentaje de control de malezas. El porcentaje de control de la primera aplicación post-emergente en términos reducción de individuos fue de 29% en la zona Centro, 34% en Meseta y 52% en Norte. El porcentaje de control de los herbicidas de la segunda aplicación post-emergente en disminución de densidad de malezas fue de 7%, 5% y 22% en las zonas Centro, Meseta y Norte respectivamente. Dichos niveles de control suprimen las poblaciones de malezas y evitan un efecto negativo mayor sobre el cultivo. La zona Norte exhibe mayor porcentaje de control.Abstract. Weeds are a severe problem in all rice’s crops around the world. The present study was made between July 2012 and February 2013 with the aimed to study population behavior of weeds associated with the cultivation in three areas of Tolima (Colombia).This study was carried out by sampling weed community of crops located in areas Centro, Meseta y Norte. Weed evaluations in the fields occurred in 96 hectares distributed according to area planted in each zone. This procedure was made using squares (20 x 20 cm). These evaluations were made before and after each one of post-emergence herbicide applications like this: the first one between 7 and 22 days after sowing (before early post-emergence application), the second one between 22 and 35 d.a.s (after early post-emergence application), the third one between 37 and 52 d.a.s (after medium post-emergence application) and the fourth one between 52 and 65 d.a.s (at the end of control applications). In each sampling were identified each one of weeds and were evaluated variables like frequency, density, coverage and percent control of weeds. Recognition and study of weed community structure in three areas through these variables allowed obtaining diversity index, coefficients of similarity and importance value index. The importance value index showed that the five most important weeds in the department are: Echinochloa Colona, Digitaria ciliaris, Cyperus iria, Ischaemum rugosum and Murdannia nudiflora. For the Central región are: Rottboellia cochinchinensis, Echinochloa Colona, Cyperus iria, Ischaemum rugosum and Leptochloa scabra. In the Meseta are: Cyperus iria, Echinochloa Colona, Digitaria bicornis, Eclipta alba and Ischaemum rugosum. To the Norte: Digitaria ciliaris, Echinochloa Colona, Cyperus iria, Murdannia nudiflora and Paspalum boscianum. Shannon-Wiener index and Simpson index show greater diversity in the Meseta. The Jaccard and Sorensen index showed that there is dissimilarity in the community structure of the areas evaluated. Efficiency of these herbicides was evaluated through density of the sampled species and percent of weed control. First post-emergence applications reduced weed density in 29% for Centro zone, 34% in Meseta and 52% in Norte. Percent of weed control of this application in Centro zone was 57%, 63% in Meseta and 67% in Norte. Second post-emergence applications reduced in 7%, 5% and 22% weed density for Centro, Meseta and Norte zones, respectively. Percent of weed control of this application for Centro zone was 61%, 53% in Meseta and 64% in Norte. These control rates suppress weeds’ populations sufficiently and avoid a greater negative effect. Norte zone show a greater reduction for weed density and a bigger percent of control.Maestrí
Esqueda Esquivel, Valentín Alberto - One of the best experts on this subject based on the ideXlab platform.
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Validación de Cihalofop-Butilo + Clomazone para el control de "Echinochloa Colona" (L.) Link en arroz de temporal
Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias (INIFAP), 2014Co-Authors: Esqueda Esquivel, Valentín Alberto, Tosquy Valle, Óscar HugoAbstract:During seasonal cycles 2011 and 2012, four plots were established in the municipality of rice Tres Valles, Veracruz, in order to validate the experimental results of control of leg scorer grass [Echinochloa Colona (L.) Link] with cyhalofop butyl + clomazone, compare their efficiency and profitability with the regional treatment and knowledge transfer of new technology to rice farmers from the center of the state of Veracruz. Both treatments were compared: 1-butyl Cyhalofop clomazone + 315 + 480 g ha-1; and 2. Propanil followed by propanil (regional treatment) in different doses each cycle according to the size of E. Colona. Both cycles E. Colona control and toxicity to rice at 25, 35 and 60 days after application of treatments was evaluated. Performance of paddy rice was also quantified and profitability of the treatments was determined. With cyhalofop butyl + clomazone end E. Colona control was 91.25%, and the average yield of paddy rice in 5 033 kg ha-1, while the regional treatment these values were 49.50% and 2 883 kg ha-1, respectively. The benefit/cost with cyhalofop butyl clomazone + ratio was 1.507, much higher than the traditional treatment (0.802), primarily driven by higher grain yield obtained and a lower cost of control. New technology to 71 people, including rice farmers and technicians, transferred through two field demonstrations.Durante los ciclos de temporal 2011 y 2012, se establecieron cuatro parcelas en arrozales del municipio de Tres Valles, Veracruz, con objeto de validar los resultados experimentales de control del zacate pata de pichichi [Echinochloa Colona(L.) Link] con cihalofop-butilo + clomazone, comparar su eficiencia y rentabilidad con el tratamiento regional, y transferir el conocimiento de la nueva tecnología a los productores de arroz del centro del estado de Veracruz. Se compararon dos tratamientos: 1. Cihalofop-butilo + clomazone a 315 + 480 g ha-1 ; y 2. Propanil seguido de propanil (tratamiento regional) en dosis diferentes cada ciclo de acuerdo al tamaño de E. Colona. En ambos ciclos se evaluó el control de E. Colona y la toxicidad al arroz a los 25, 35 y 60 días después de la aplicación de los tratamientos. También se cuantificó el rendimiento de arroz palay se determinó la rentabilidad de los tratamientos. Con cihalofop-butilo + clomazone el control final de E. Colona fue 91.25%, y el rendimiento promedio de arroz palay de 5 033 kg ha-1, mientras que con el tratamiento regional estos valores fueron de 49.50% y 2 883 kg ha-1, respectivamente. La relación beneficio/costo con cihalofop-butilo + clomazone fue de 1.507, mucho mayor que la del tratamiento tradicional (0.802), principalmente por un mayor rendimiento de grano obtenido y un menor costo de control. La nueva tecnología se transfirió a 71 personas, entre productores de arroz y técnicos, a través de dos demostraciones de campo
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Control de malezas en arroz de temporal con clomazone, solo y en mezcla con propanil y 2,4-D
2000Co-Authors: Esqueda Esquivel, Valentín AlbertoAbstract:Three experiments were carried out in order to evaluate the effect of the herbicide clomazone, alone and mixed with propanil and 2,4-D on weed control and toxicity to rice cv. Milagro Filipino, growing under upland conditions. All the experiments were established in Los Naranjos, a rice-growing area located in the Municipality of Tres Valles, in the state of Veracruz. The dominant weed species in the experimental plots were Cyperus iria, Echinochloa Colona, Cyperus rotundus, Scleria setuloso-ciliata and Malachra fasciata. Clomazone applied preemergent, efficiently controlled E. Colona at 0,72 and 0,96 kg a. i./ha, but its effect was partial and temporary on S. setuloso-ciliata and it had no effect on C. iria and C. rotundus. Mixture of clomazone + propanil + 2,4-D efficiently controlled E. Colona and C. iria from 0.60 + 1.44 + 0.24 kg a. i./ha. It also had a good initial control of C. rotundus, but its effect was completely lost between 45 and 60 days after the application and its effect on S. setuloso-ciliata was influenced by the soil moisture: the higher the moisture the better this weed was controlled and viceversa. Rice grain yields obtained in plots where clomazone, alone or mixed with propanil and 2,4-D was applied were statistically similar to those obtained in plots where the weed control regional treatment was applied.Se establecieron tres experimentos con el objetivo de evaluar el efecto del herbicida clomazone sólo y en mezcla con propanil y 2,4-D en el control de malezas y la toxicidad al arroz cv. Milagro Filipino desarrollado en condiciones de temporal. Los tres experimentos se establecieron en la zona arrocera de Los Naranjos, localizada en el Mpio. de Tres Valles en el estado de Veracruz. Las especies dominantes de malezas fueron: Cyperus iria, Echinochloa Colona, Cyperus rotundus, Scleria setuloso- ciliata y Malachra fasciata. El clomazone aplicado en preemergencia, controló eficientemente E. Colona en dosis de 0,72 y 0,96 kg i.a./ha, pero tuvo un efecto temporal y limitado sobre S. setuloso-ciliata y no tuvo efecto sobre C. iria y C. rotundus. La mezcla de clomazone + propanil + 2,4-D controló E. Colona y C. iria a partir de la dosis de 0,60 + 1,44 + 0,24 kg i.a./ha. Asimismo, tuvo un buen control inicial de C. rotundus, pero su efecto sobre esta especie se perdió entre los 45 y 60 días después de la aplicación y su efecto sobre S. setuloso-ciliata estuvo influenciado por las condiciones de humedad en el terreno, a mayor humedad se tuvo mejor control de esta maleza y viceversa. En todos los casos, los rendimientos de arroz palay obtenidos con los tratamientos en donde se aplicó el clomazone sólo o en mezcla con propanil y 2,4-D, fueron estadísticamente semejantes a los obtenidos en los testigos regionales
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Control de malezas en arroz de temporal con clomazone, propanil y 2,4-D
1999Co-Authors: Esqueda Esquivel, Valentín AlbertoAbstract:Between 1996 and 1997, three experiments were carried out in order to evaluate the effect of the herbicide clomazone, alone and mixed with propanil and 2,4-D on weed control and toxicity to rice cv. Milagro Filipino, growing under upland conditions. All the experiments were established in Los Naranjos, in the Municipality of Tres Valles, in the state of Veracruz. The dominant weed species in the experimental plots were Cyperus iria, Echinochloa Colona, Cyperus rotundus, Scleria setuloso-ciliata and Malachra fasciata. Clomazone applied preemergent, efficiently controlled E. Colona at 0.72 and 0.96 kg a. i./ha, but its effect was partial and temporary on S. setuloso-ciliata and it had no effect on C. iria and C. rotundus. The mixture of clomazone + propanil + 2,4-D efficiently controlled E. Colona and C. iria from 0.60 + 1.44 + 0.24 kg a. i./ha and had a good initial control of C. rotundus, but its effect disappeared 45 to 60 days after the application. Rice yields obtained from clomazone treatments, alone or mixed with propanil and 2,4-D were statistically similar to those of the regional controls.Entre los años de 1996 y 1997 se establecieron tres experimentos con el objetivo de evaluar el efecto del herbicida clomazone solo y en mezcla con propanil y 2,4-D en el control de malezas y la toxicidad al arroz cv. Milagro Filipino desarrollado en condiciones de temporal. Los tres experimentos se establecieron en Los Naranjos, Mpio. de Tres Valles en el estado de Veracruz. Las especies dominantes de malezas fueron: Cyperus iria, Echinochloa Colona, Cyperus rotundus, Scleria setuloso-ciliata y Malachra fasciata. El clomazone aplicado en preemergencia, controló eficientemente E. Colona en dosis de 0,72 y 0,96 kg i.a./ha, pero sólo tuvo un efecto temporal y limitado sobre S. setuloso-ciliata y no tuvo efecto sobre C. iria y C. rotundus. La mezcla de clomazone + propanil + 2,4-D controló eficientemente E. Colona y C. iria a partir de la dosis de 0,60 + 1,44 + 0,24 kg i.a./ha, y tuvo un buen control inicial de C. rotundus, pero su efecto sobre esta especie desapareció entre los 45 y 60 días después de la aplicación. Los rendimientos de arroz obtenidos en los tratamientos en donde se aplicó clomazone solo o en mezcla con propanil y 2,4-D, fueron estadísticamente semejantes a los obtenidos en los testigos
Bernal E Valverde - One of the best experts on this subject based on the ideXlab platform.
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rapid detection of propanil and fenoxaprop resistance in Echinochloa Colona
Weed Science, 2000Co-Authors: John C Caseley, Charles R Riches, P Brain, Bernal E ValverdeAbstract:Abstract Rapid detection methods were developed for discriminating between resistant (R) and susceptible (S) biotypes of Echinochloa Colona to either propanil or fenoxaprop-P at all growth stages. In the pregerminated seed assay for fenoxaprop-P, seeds were placed on 1.0% agar containing a range of concentrations of herbicides and kept under humid conditions. For propanil, pregerminated seeds were placed on moist filter paper in the lid of a petri dish and, when one leaf had developed, the lid was inverted for 1 min into propanil solutions at a range of concentrations. For the fenoxaprop-P and propanil test, seedling length and fresh weight were measured after 1 wk. For juvenile plants with four-leaf to one-tiller, shoots and roots were trimmed and placed in 20-ml glass tubes containing 0.2% (wt/v) agar and a range of concentrations of herbicides. Shoot extension and weight were recorded after 7 d. Larger plants with several small tillers were also assayed by this method. Tillers were removed from larger ...
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the role of pendimethalin in the integrated management of propanil resistant Echinochloa Colona in central america
Pesticide Science, 1997Co-Authors: Charles R Riches, Julia S Knights, Lilliana Chaves, John C Caseley, Bernal E ValverdeAbstract:Pre-emergence activity of pendimethalin on propanil-resistant jungle rice (Echinochloa Colona) was demonstrated in glasshouse trials. Both susceptible and resistant populations, collected from Costa Rica, were controlled by 1.25 kg ha -1 , the usual application rate used in the field where Rottboellia cochinchinensis is also a problem. When applied post-emergence, propanil performance was improved by the addition of low doses of pendimethalin to the herbicide mixture. A propanil-resistant selection was controlled by 0.23 kg ha -1 pendimethalin + 0.54 kg ha -1 propanil at the one-to-two leaf stage, and 0.23 kg ha -1 pendimethalin + 1.08 kg propanil at the three-to-four leaf stage compared to 1.08 kg and 2.16 kg ha -1 respectively when propanil was applied alone. This suggests that pendimethalin improves post-emergence control in the field compared to the standard propanil treatment and can provide residual pre-emergence control of late-germinating individuals, so reducing the propanil selection pressure. For effective jungle rice control, growers apply propanil (3.84 kg ha -1 ) at 10 and 20 days after planting (DAP) followed by one application of fenoxaprop-P-ethyl (0.045 kg ha -1 ) at 35 DAP. Field experiments, conducted in dry-seeded upland rice in southern Costa Rica, demonstrated that under high jungle-rice population pressure, one application of pendimethalin at 1.5 kg ha -1 provided an effective replacement for propanil, resulting in reduced weed-control costs.
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effect of mono oxygenase inhibitors on uptake metabolism and phytotoxicity of propanil in resistant biotypes of jungle rice Echinochloa Colona
Pesticide Science, 1997Co-Authors: Jon M Leah, Charles R Riches, John C Caseley, Bernal E ValverdeAbstract:The effect of the mono-oxygenase inhibitors tridiphane, piperonyl butoxide and prochloraz on propanil uptake, metabolism and phytotoxicity was measured in a resistant (R) biotype of Echinochloa Colona. The uptake of propanil was not significantly affected by any of the three mono-oxygenase inhibitors. The first metabolite of propanil metabolism, 3,4-dichloroaniline, was found to accumulate to higher levels in E. Colona treated with each of the mono-oxygenase inhibitors mixed with formulated propanil, compared to propanil applied alone. Accumulation of further metabolites of propanil (glucosyl-3,4-dichloroaniline and bound products) was reduced in the presence of mono-oxygenase inhibitors, compared with propanil application alone. Leaf damage caused by a single drop of propanil compared to propanil + mono-oxygenase inhibitor was used to assess the degree of propanil tolerance in E. Colona biotypes. Leaf damage was significantly greater in propanil + mono-oxygenase inhibitor treatments. No leaf damage was observed in mono-oxygenase inhibitor treatments alone at the concentrations used. Peroxidase activity was measured in crude extracts of the R-biotype of E. Colona using 3,4-dichloroaniline as substrate, in the presence and absence of mono-oxygenase inhibitors and the specific peroxidase inhibitor salicylhydroxamic acid. Peroxidase activity was inhibited by all three mono-oxygenase inhibitors at 10 μM and by salicylhydroxamic acid at 1 μm. Glucosyl-3,4-dichloroaniline was found not to be a substrate for peroxidase activity. These results suggest that the incorporation of 3,4-dichloroaniline into bound residues involves peroxidase activity which can be inhibited by mono-oxygenase inhibitors. When peroxidase activity is inhibited, the precursor metabolite 3,4-dichloroaniline accumulates, and propanil resistance in E. Colona is reduced, possibly as a consequence of phytotoxicity of this metabolite and/or product inhibition of the first step in propanil metabolism, responsible for the formation of 3,4-dichloroaniline. Glasshouse trials have demonstrated that the application of mono-oxygenase inhibitors, (particularly tridiphane which is also known to inhibit glutathione transferase activity) with propanil offers a promising approach to the control of propanil resistant biotypes of Jungle-Rice.
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effect of mono oxygenase inhibitors on uptake metabolism and phytotoxicity of propanil in resistant biotypes of jungle rice Echinochloa Colona
Pesticide Science, 1997Co-Authors: Jon M Leah, Charles R Riches, John C Caseley, Bernal E ValverdeAbstract:The effect of the mono-oxygenase inhibitors tridiphane, piperonyl butoxide and prochloraz on propanil uptake, metabolism and phytotoxicity was measured in a resistant (R) biotype of Echinochloa Colona. The uptake of propanil was not significantly affected by any of the three mono-oxygenase inhibitors. The first metabolite of propanil metabolism, 3,4-dichloroaniline, was found to accumulate to higher levels in E. Colona treated with each of the mono-oxygenase inhibitors mixed with formulated propanil, compared to propanil applied alone. Accumulation of further metabolites of propanil (glucosyl-3,4-dichloroaniline and bound products) was reduced in the presence of mono-oxygenase inhibitors, compared with propanil application alone. Leaf damage caused by a single drop of propanil compared to propanil + mono-oxygenase inhibitor was used to assess the degree of propanil tolerance in E. Colona biotypes. Leaf damage was significantly greater in propanil + mono-oxygenase inhibitor treatments. No leaf damage was observed in mono-oxygenase inhibitor treatments alone at the concentrations used. Peroxidase activity was measured in crude extracts of the R-biotype of E. Colona using 3,4-dichloroaniline as substrate, in the presence and absence of mono-oxygenase inhibitors and the specific peroxidase inhibitor salicylhydroxamic acid. Peroxidase activity was inhibited by all three mono-oxygenase inhibitors at 10 μM and by salicylhydroxamic acid at 1 μm. Glucosyl-3,4-dichloroaniline was found not to be a substrate for peroxidase activity. These results suggest that the incorporation of 3,4-dichloroaniline into bound residues involves peroxidase activity which can be inhibited by mono-oxygenase inhibitors. When peroxidase activity is inhibited, the precursor metabolite 3,4-dichloroaniline accumulates, and propanil resistance in E. Colona is reduced, possibly as a consequence of phytotoxicity of this metabolite and/or product inhibition of the first step in propanil metabolism, responsible for the formation of 3,4-dichloroaniline. Glasshouse trials have demonstrated that the application of mono-oxygenase inhibitors, (particularly tridiphane which is also known to inhibit glutathione transferase activity) with propanil offers a promising approach to the control of propanil resistant biotypes of Jungle-Rice.
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age related mechanisms of propanil tolerance in jungle rice Echinochloa Colona
Pesticide Science, 1995Co-Authors: Jon M Leah, Charles R Riches, John C Caseley, Bernal E ValverdeAbstract:Uptake and metabolism of propanil were measured in both susceptible (S) and resistant (R) biotypes of Jungle-rice, Echinochloa Colona (L.) link at different growth stages. Results showed that there was no significant difference in uptake between S and R biotypes of E. Colona at any given growth stage, but that uptake was significantly reduced at older plant growth stages in all biotypes studied. Metabolism of propanil was more rapid in R biotypes than in S biotypes at all growth stages studied. Specific and total aryl acylamidase activity, responsible for the first stage of propanil metabolism, was higher in R biotypes than in S at all growth stages, but declined to about 50% of the maximum at older growth stages, confirming the importance of this enzyme in conferring resistance to this herbicide. The area of necrosis that developed around a single drop of propanil deposited on the adaxial leaf surface was used to assess the degree of propanil resistance; it was found that resistance increased at older E. Colona growth stages in contrast to the rate of propanil metabolism and amidase activity. Treatment of leaves with the amidase inhibitors, carbaryl or piperophos, simultaneously with propanil, caused a decrease in resistance at growth stages where amidase activity was greatest. This treatment was less effective at older growth stages. These results show that, in E. Colona, propanil metabolism is important for conferring resistance in younger plants (four-six-leaf stage). It is suggested that restricted uptake confers resistance in older plants
Chauhan, Bhagirath Singh - One of the best experts on this subject based on the ideXlab platform.
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Effectiveness of glufosinate, dicamba, and clethodim on glyphosate-resistant and susceptible populations of five key weeds in Australian cotton systems
'Cambridge University Press (CUP)', 2021Co-Authors: Werth, Jeff A., Keenan Michelle, Thormby David, Hereward James, Chauhan, Bhagirath SinghAbstract:XtendFlexTM cotton with resistance to glyphosate, glufosinate and dicamba may become available in Australia. Resistance to these herbicides enables two additional modes of action to be applied in crop. The double knock strategy, typically glyphosate followed by paraquat, has been a successful tactic for control of glyphosate-resistant in fallow situations in Australia. Glufosinate is a contact herbicide, and may be useful as the second herbicide in a double knock for use in XtendFlexTM cotton crops. We tested the effectiveness of glufosinate applied at intervals of 1, 3, 7, and 10 d after initial applications of glyphosate, dicamba, clethodim and glyphosate mixtures with dicamba or clethodim on glyphosate-resistant and susceptible populations of Conyza bonariensis, Sonchus oleraceus, Chloris virgata, Chloris truncata and Echinochloa Colona. Effective treatments for Conyza bonariensis with 100% control were dicamba and glyphosate+dicamba followed by glufosinate independent of the interval between applications. Sonchus oleraceus was effectively controlled in Experiment 1 by all treatments. However, in Experiment 2 effective treatments were dicamba and glyphosate+dicamba followed by glufosinate (99.3 – 100% control). Timing of the follow-up glufosinate did not affect the control achieved. Consistent control of Chloris virgata was achieved with glyphosate, clethodim or glyphosate+clethodim followed by glufosinate at 7 and 10 d intervals (99.7 – 100% control). Control of Chloris truncata was inconsistent. The best treatment for C. truncata was glyphosate+clethodim followed by glufosinate 10 d later (99.8 – 100% control). Echinochloa Colona was effectively controlled with all treatments except for glyphosate on the glyphosate-resistant population. Additional in-crop use of glufosinate and dicamba should be beneficial for weed management in XtendFlexTM cotton crops, when utilising the double knock tactic with glufosinate. For effective herbicide resistance management, it is important that these herbicides be used in addition to, rather than substitution for, existing weed management tactics
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The response of glyphosate-resistant and glyphosate-susceptible biotypes of Echinochloa Colona to carbon dioxide, soil moisture and glyphosate
'Springer Science and Business Media LLC', 2020Co-Authors: Mollaee Mahboobeh, Mobli Ahmadreza, Chauhan, Bhagirath SinghAbstract:Physiological and growth responses of two Australian Echinochloa Colona biotypes (glyphosate-resistant and susceptible, produced from a single population) to different concentrations of carbon dioxide (CO2) (ambient ~450 ppm and elevated ~750 ppm) and soil moisture (well-watered and water-stressed) were analyzed. Elevated CO2 and well-watered conditions resulted in E. Colona plants with greater biomass, height and numbers of tillers and leaves in both biotypes; however, no significant response was observed for seed production or the amount of photosynthesis pigments with increasing CO2 at both soil moisture levels. In addition, water availability was more influential for growth than CO2 concentration. The mean shoot biomass of the susceptible biotype under elevated CO2 and well-watered conditions was significantly greater than the resistant biotype. Although the susceptible biotype showed more vegetative and reproductive growth than the resistant biotype, no significant difference was observed for seed production between the biotypes in the water-stressed condition. In a second experiment, different doses of glyphosate (0, 180, 360, 720 and 1440 g a.e ha-1) were applied to both biotypes grown at two soil moisture levels (well-watered and water-stressed). In the water-stressed condition, glyphosate efficacy was decreased in both biotypes. The resistant biotype in the well-watered condition had only 19% survival at 1440 g ha-1 glyphosate (double the recommended rate), but this value increased in the water-stressed condition by 62%. Our study suggests that future climate change can affect the physiological and growth processes of weeds and their responses to herbicides. Knowledge of their adapting behaviors will be critical to weed management strategies
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Effects of sorghum residue in presence of pre-emergence herbicides on emergence and biomass of Echinochloa Colona and Chloris virgata
'Public Library of Science (PLoS)', 2020Co-Authors: Mobli Ahmadreza, Rinwa Abhimanyu, Chauhan, Bhagirath SinghAbstract:In conservation agriculture systems, farmers gain many advantages from retaining crop residue on the soil surface, but crop residue retention in these systems may intervene with the activity of pre-emergence herbicides. A pot study was conducted to evaluate the effect of different rates of pre-emergence herbicides [imazethapyr (100 and 150 g a. i. ha-1), isoxaflutole (100 and 200 g a. i. ha-1), metolachlor (1.5 and 2.25 kg a. i. ha-1), pendimethalin (2.25 and 3.38 kg a. i. ha-1) and prosulfocarb + metolachlor (2.5 and 3.75 kg a. i. ha-1)] on seedling emergence and biomass of Echinochloa Colona and Chloris virgata when applied in the presence of sorghum residue at rates equivalent to (0, 3 and 6 t ha-1). When seeds of E. Colona and C. virgata were not covered with sorghum residue, the seedling emergence and biomass of both weeds was inhibited by 93–100% and 56–100%, respectively, with the application (both rates) of isoxaflutole, metolachlor, pendimethalin and prosulfocarb + metolachlor. Using sorghum residue resulted in lower herbicide efficacy on both weeds. At 3 t ha-1 sorghum residue, E. Colona emergence and biomass reduced by 38–100% and 30–100%, respectively, with application of isoxaflutole, metolachlor and pendimethalin (both rates) in comparison with the no-herbicide treatment. Similarly, the emergence and biomass of C. virgata was also reduced by 92–100% and 25–100%, respectively. The results of this study suggest that crop residue may influence efficacy of commonly used pre-emergence herbicides and that the amount of crop residue on the soil surface should be adjusted according to the nature of the pre-emergence herbicides to achieve adequate weed control
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Effects of sorghum residue in presence of preemergence herbicides on emergence and biomass of Echinochloa Colona and Chloris virgata
'Public Library of Science (PLoS)', 2020Co-Authors: Mobli Ahmadreza, Rinwa Abhimanyu, Chauhan, Bhagirath SinghAbstract:In conservation agriculture systems, farmers gain many advantages from retaining crop residue on the soil surface, but crop residue retention in these systems may intervene with the activity of pre-emergence herbicides. A pot study was conducted to evaluate the effect of different rates of pre-emergence herbicides [imazethapyr (100 and 150 g a. i. ha), isoxaflutole (100 and 200 g a. i. ha), metolachlor (1.5 and 2.25 kg a. i. ha), pendimethalin (2.25 and 3.38 kg a. i. ha) and prosulfocarb + metolachlor (2.5 and 3.75 kg a. i. ha)] on seedling emergence and biomass of Echinochloa Colona and Chloris virgata when applied in the presence of sorghum residue at rates equivalent to (0, 3 and 6 t ha). When seeds of E. Colona and C. virgata were not covered with sorghum residue, the seedling emergence and biomass of both weeds was inhibited by 93-100% and 56-100%, respectively, with the application (both rates) of isoxaflutole, metolachlor, pendimethalin and prosulfocarb + metolachlor. Using sorghum residue resulted in lower herbicide efficacy on both weeds. At 3 t ha sorghum residue, E. Colona emergence and biomass reduced by 38-100% and 30-100%, respectively, with application of isoxaflutole, metolachlor and pendimethalin (both rates) in comparison with the no-herbicide treatment. Similarly, the emergence and biomass of C. virgata was also reduced by 92-100% and 25-100%, respectively. The results of this study suggest that crop residue may influence efficacy of commonly used pre-emergence herbicides and that the amount of crop residue on the soil surface should be adjusted according to the nature of the pre-emergence herbicides to achieve adequate weed control
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Growth behavior and glyphosate resistance level in 10 populations of Echinochloa Colona in Australia
'Public Library of Science (PLoS)', 2020Co-Authors: Mahajan Gulshan, Kaur Vishavdeep, Thompson Michael, Chauhan, Bhagirath SinghAbstract:Recently, poor control of Echinochloa Colona with glyphosate has been reported in no-till agriculture systems of the northern grain region (NGR) of Australia. Two experiments were conducted using 10 populations of E. Colona selected from the NGR of Australia to understand differences in their growth behavior and resistance pattern. Growth studies revealed that these populations differed in plant height (53-70 cm plant-1), tiller production (30-52 tillers plant-1), leaf production (124-186 leaves plant-1) and seed head production (37-65 seed heads plant-1). Days taken to seed heads and shoot biomass in these populations ranged between 40-48 d and 21-27 g plant-1, respectively. Seed production in these populations ranged between 5380 and 10244 seeds plant-1; lowest for population B17/25 and highest for population B17/13. Correlation studies revealed that seed number plant-1 had a positive correlation with tiller number plant-1 (r = 0.73) and negative relation with days taken to seed head initiation (r = - 0.65). The glyphosate dose-response study showed a wide range of responses in these populations and the glyphosate dose required to kill 50% plants (LD50 values) was estimated between 161 to 2339 g a.e. glyphosate ha-1. LD50 values of populations B17/16, B 17/34 and B17/35 were 1086, 2339 and 1153 g ha-1, respectively, making them 6.7, 15.1 and 7.2-fold resistant to glyphosate compared with the susceptible population B17/37. Growth behavior and seed production potential in these populations had no correlation with the resistance index. These results suggest that some populations of E. Colona are highly problematic; for example, population B17/34 was not only highly glyphosate-resistant, but also produced a high seed number (9300 seeds plant-1). This study demonstrated that there is a possibility of great risk with the increased use of glyphosate for managing E. Colona in the NGR of Australia. The results warrant integrated weed management strategies and improved stewardship guidelines are required for managing glyphosate-resistant populations of E. Colona and to restrict further movement of resistant populations to other regions of Australia
