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Together, Conyza bonariensis, C. canadensis and C. sumatrensis show 105 reported cases of biotypes resistant to herbicides like glyphosate, paraquat, and acetolactate synthase (ALS) inhibitors. The application of pre-emergent herbicides combined with burndown herbicides is believed to be effective in controlling Conyza spp. during soybean pre-sowing management. The objective of this study was to evaluate the efficacy of sulfentrazone/diuron, imazethapyr/flumioxazin, and diclosulam in mixtures with diquat, paraquat, or glufosinate on the control of Conyza spp. Two field experiments were conducted in a randomized block design with four replicates. Treatments consisted of the application of pre-emergent plus burndown herbicides, besides the weedy control treatment (without application), for a total of 10 treatments. The control of Conyza spp. was evaluated at 7, 14, 21, 28, and 35 d after herbicide application, and symptoms of injury in soybean plants were evaluated at 14, 21, 28, and 35 d after herbicide application. The herbicides sulfentrazone/diuron, imazethapyr/flumioxazin, and diclosulam in combination with burndown herbicides diquat, paraquat, or glufosinate were effective in controlling Conyza spp. in the pre-sowing management of soybean, highlighting good options for pre- and post-emergent herbicide rotations. Mixtures with diclosulam showed a higher potential for injury to soybean plants than sulfentrazone/diuron and imazethapyr/flumioxazin., Juntas, Conyza bonariensis, C. canadensis y C. sumatrensis presentan 105 casos reportados de biotipos resistentes a herbicidas tales como glifosato, paraquat y los inhibidores de la acetolactato sintasa (ALS). Se cree que la aplicación de herbicidaspre-emergentes en mezclas con desecantes es efectiva para controlar Conyza spp. en el manejo pre-siembra de la soya. El objetivo de este estudio fue evaluar la eficacia de sulfentrazona/diuron, imazetapir/flumioxazin y diclosulam, en mezcla con diquat, paraquat o glufosinato, en el control de Conyza spp. Se realizaron dos experimentos de campo en diseño de bloques al azar con cuatro repeticiones. Los tratamientos consistieron en la aplicación de herbicidas pre-emergentes en mezclas con desecantes, además del tratamiento control (sin aplicación), para un total de 10 tratamientos. El control de Conyza spp. se evaluó a los 7, 14, 21, 28 y 35 d después de la aplicación del herbicida, y se evaluaron los síntomas de daño en las plantas de soya a los 14, 21, 28 y 35 d después de la aplicación del herbicida. Los herbicidas sulfentrazona/diuron, imazetapir/flumioxazin y diclosulam en mezclas con diquat, paraquat o glufosinato, fueron efectivos para controlar Conyza spp. en la pre-siembra de la soya, destacando buenas opciones para la rotación de herbicidas antes y después de la emergencia. Las mezclas con diclosulam mostraron un mayor potencial de daño a las plantas de soya que sulfentrazona/diuron y imazetapir/flumioxazin.

Knowledge of the environmental and transport fate of pesticides is integral to characterizing environmental exposures. Agencies such as the Environmental Protection Agency (EPA) 27 integrate the characterization of an exposure with ecological effects to determine the risks of pesticide use. The three most widely used herbicides in Colombia are glyphosate, propanil, and glufosinate ammonium. Although glyphosate had, since the early 1970’s, been considered an environmentally friendly herbicide, the weight of the evidence of studies beginning in the 1990s show that inadvertent applications in wetlands can be fatal to the larvae of amphibians. Although glyphosate formulations are typically considered moderately toxic (LC50 = 1-10 ppm) for most aquatic organisms, for many amphibian species they are highly toxic (LC50 ˂ 1 ppm). This concern is compounded by the fact that Colombia has an incredibly high diversity of amphibians (746 species). In addition, chronic exposures of some amphibian species to sublethal concentrations, which are more likely found in the environment, have been shown to cause decreased survival, intersex gonads, tail damage, prolongation of time to metamorphosis, and liver lipidosis. In Colombia, aerial applications of Glyphos-Cosmo-Flux have been used since 1997 to fumigate illicit coca crops. As of 2019, the International Union for Conservation of Nature (IUCN) Red List had 285 species of amphibians in Colombia considered threatened. We found that 132 of the endangered (EN) and critically endangered (CR) amphibian species were present in 11 of the 32 Colombian departments with illegal coca plantations. Therefore, studies are needed to evaluate the impact of the coca eradication program on the amphibian population of the country. Propanil is the main herbicide used in rice fields. Despite its rapid environmental degradation ((1 day in aerobic conditions), studies on the impact of propanil have found that at projected application rates (4.5 k, Resumo O conhecimento do destino ambiental e de transporte dos pesticidas é parte integrante da caracterização das exposições ambientais. Agências como a Agência de Proteção Ambiental (EPA) 27 integram a caracterização de uma exposição com efeitos ecológicos para determinar os riscos do uso de pesticidas. Os três herbicidas mais usados na Colômbia são glifosato, propanil e glufosinato de amônio. Embora o glifosato tenha sido considerado um herbicida ambientalmente correto desde o início da década de 1970, foi evidenciado por estudos iniciados na década de 1990 que aplicações inadvertidas em pântanos podem ser fatais para larvas de anfíbios. Embora as formulações de glifosato sejam tipicamente consideradas moderadamente tóxicas (CL50 = 1-10 ppm) para a maioria dos organismos aquáticos, para muitas espécies de anfíbios elas são altamente tóxicas (CL50 ˂ 1 ppm). Essa preocupação é agravada pelo fato de que a Colômbia tem uma diversidade incrivelmente alta de anfíbios (791 espécies). Além disso, foi demonstrado que exposições crônicas de algumas espécies de anfíbios a concentrações subletais, que são mais prováveis no ambiente, causam diminuição da sobrevivência, gônadas intersex, dano na cauda, prolongamento do tempo até a metamorfose e lipidose hepática. Na Colômbia, aplicações aéreas de Glyphos-Cosmo-Flux têm sido usadas desde 1997 para fumigar plantações ilícitas de coca. Em 2019, a Lista Vermelha da União Internacional para a Conservação da Natureza (IUCN) tinha 285 espécies de anfíbios na Colômbia consideradas ameaçadas. Descobrimos que 132 das espécies de anfíbios em perigo (EN) e criticamente em perigo (CR) estavam presentes em 11 dos 32 departamentos colombianos onde há mais plantações ilegais de coca. Portanto, são necessários estudos para avaliar o impacto do programa de erradicação da coca na população de anfíbios do país. O propanil é o principal herbicida usado nos campos de arroz. Apesar de sua rápida degradação ambiental ((1 dia em condições aeróbicas), resumen está disponible en el texto completo

Introduction. Certain naturally derived substances may have herbicidal activity on some weeds species. Objective. To evaluate the efficacy of three substances of natural origin for the control of four weed species and to compare it with the effect of a synthetic broad-spectrum herbicide. Materials and methods. In February 2017, an experiment was conducted in a greenhouse at the Fabio Baudrit Moreno Agricultural Experiment Station, Universidad de Costa Rica. Three commercial products of natural origin based on: 55 % d-limonene, 15% pine extract (Pinus sp.) and 23% thyme extract (Thymus vulgaris) were evaluated; additionally, a product of synthetic origin, gluphosinate ammonium 14 SL, was evaluated. A none treated check was included. These were sprayed on seedlings of Bidens pilosa, Amaranthus sp., Echinochloa colona and Rottboellia cochinchinensis. Results. The seedlings sprayed with the natural herbicides showed symptoms at two hours, but their final efficacy varied among species. Eight-days after spraying, d-limonene was more effective than all other treatments, showing damage ratings higher than 4.25 in all species. Pine and thyme extracts were not effective on B. pilosa. Pine extract caused greater damage on Amaranthus sp, E. colona, and R. cochinchinensis, while the thyme extract caused greater damage on Amaranthus sp and R. cochinchinensis. The synthetic herbicide gluphosinate showed significant damage on all four species. Conclusions. The commercial products of natural origin used had herbicidal activity on the four weed species tested., Introducción. Ciertas sustancias de origen natural pueden tener actividad herbicida sobre algunas especies de arvenses. Objetivo. Evaluar la eficacia de tres sustancias de origen natural para el control de cuatro especies de arvenses y compararla con el efecto de un herbicida sintético de amplio espectro. Materiales y métodos. En febrero del 2017 se condujo un experimento en un invernadero en la Estación Experimental Agrícola Fabio Baudrit Moreno, de la Universidad de Costa Rica. Se evaluaron tres productos comerciales de origen natural a base de: d-limoneno al 55 %, extracto de pino al 15 % (Pinus sp.) y extracto de tomillo al 23 % (Thymus vulgaris); además, se evaluó un producto de origen sintético, glufosinato de amonio 14 SL. Se incluyó un testigo absoluto. Estos se asperjaron sobre plantas de Bidens pilosa, Amaranthus sp., Echinochloa colona y Rottboellia cochinchinensis. Resultados. Las plantas asperjadas con los herbicidas naturales mostraron síntomas a las dos horas, pero su eficacia final varió entre especies. A los ocho días después de la aspersión el d-limoneno resultó más eficaz que todos los demás tratamientos, mostró grados de daño mayores a 4,25 en todas las especies. Con el extracto de pino y el extracto de tomillo no se obtuvo eficacia sobre B. pilosa. El extracto de pino causó mayores daños en Amaranthus sp, E. colona y R. cochinchinensis, mientras que el extracto de tomillo en Amaranthus sp y R. cochinchinensis. El herbicida sintético glufosinato mostró daños significativos en las cuatro especies. Conclusiones. Los productos comerciales de origen natural utilizados, tuvieron actividad herbicida sobre las cuatro especies de arvenses evaluadas.

Together, Conyza bonariensis, C. canadensis and C. sumatrensis show 105 reported cases of biotypes resistant to herbicides like glyphosate, paraquat, and acetolactate synthase (ALS) inhibitors. The application of pre-emergent herbicides combined with burndown herbicides is believed to be effective in controlling Conyza spp. during soybean pre-sowing management. The objective of this study was to evaluate the efficacy of sulfentrazone/diuron, imazethapyr/flumioxazin, and diclosulam in mixtures with diquat, paraquat, or glufosinate on the control of Conyza spp. Two field experiments were conducted in a randomized block design with four replicates. Treatments consisted of the application of pre-emergent plus burndown herbicides, besides the weedy control treatment (without application), for a total of 10 treatments. The control of Conyza spp. was evaluated at 7, 14, 21, 28, and 35 d after herbicide application, and symptoms of injury in soybean plants were evaluated at 14, 21, 28, and 35 d after herbicide application. The herbicides sulfentrazone/diuron, imazethapyr/flumioxazin, and diclosulam in combination with burndown herbicides diquat, paraquat, or glufosinate were effective in controlling Conyza spp. in the pre-sowing management of soybean, highlighting good options for pre- and post-emergent herbicide rotations. Mixtures with diclosulam showed a higher potential for injury to soybean plants than sulfentrazone/diuron and imazethapyr/flumioxazin., Juntas, Conyza bonariensis, C. canadensis y C. sumatrensis presentan 105 casos reportados de biotipos resistentes a herbicidas tales como glifosato, paraquat y los inhibidores de la acetolactato sintasa (ALS). Se cree que la aplicación de herbicidaspre-emergentes en mezclas con desecantes es efectiva para controlar Conyza spp. en el manejo pre-siembra de la soya. El objetivo de este estudio fue evaluar la eficacia de sulfentrazona/diuron, imazetapir/flumioxazin y diclosulam, en mezcla con diquat, paraquat o glufosinato, en el control de Conyza spp. Se realizaron dos experimentos de campo en diseño de bloques al azar con cuatro repeticiones. Los tratamientos consistieron en la aplicación de herbicidas pre-emergentes en mezclas con desecantes, además del tratamiento control (sin aplicación), para un total de 10 tratamientos. El control de Conyza spp. se evaluó a los 7, 14, 21, 28 y 35 d después de la aplicación del herbicida, y se evaluaron los síntomas de daño en las plantas de soya a los 14, 21, 28 y 35 d después de la aplicación del herbicida. Los herbicidas sulfentrazona/diuron, imazetapir/flumioxazin y diclosulam en mezclas con diquat, paraquat o glufosinato, fueron efectivos para controlar Conyza spp. en la pre-siembra de la soya, destacando buenas opciones para la rotación de herbicidas antes y después de la emergencia. Las mezclas con diclosulam mostraron un mayor potencial de daño a las plantas de soya que sulfentrazona/diuron y imazetapir/flumioxazin.

Knowledge of the environmental and transport fate of pesticides is integral to characterizing environmental exposures. Agencies such as the Environmental Protection Agency (EPA) 27 integrate the characterization of an exposure with ecological effects to determine the risks of pesticide use. The three most widely used herbicides in Colombia are glyphosate, propanil, and glufosinate ammonium. Although glyphosate had, since the early 1970’s, been considered an environmentally friendly herbicide, the weight of the evidence of studies beginning in the 1990s show that inadvertent applications in wetlands can be fatal to the larvae of amphibians. Although glyphosate formulations are typically considered moderately toxic (LC50 = 1-10 ppm) for most aquatic organisms, for many amphibian species they are highly toxic (LC50 ˂ 1 ppm). This concern is compounded by the fact that Colombia has an incredibly high diversity of amphibians (746 species). In addition, chronic exposures of some amphibian species to sublethal concentrations, which are more likely found in the environment, have been shown to cause decreased survival, intersex gonads, tail damage, prolongation of time to metamorphosis, and liver lipidosis. In Colombia, aerial applications of Glyphos-Cosmo-Flux have been used since 1997 to fumigate illicit coca crops. As of 2019, the International Union for Conservation of Nature (IUCN) Red List had 285 species of amphibians in Colombia considered threatened. We found that 132 of the endangered (EN) and critically endangered (CR) amphibian species were present in 11 of the 32 Colombian departments with illegal coca plantations. Therefore, studies are needed to evaluate the impact of the coca eradication program on the amphibian population of the country. Propanil is the main herbicide used in rice fields. Despite its rapid environmental degradation ((1 day in aerobic conditions), studies on the impact of propanil have found that at projected application rates (4.5 k, Resumo O conhecimento do destino ambiental e de transporte dos pesticidas é parte integrante da caracterização das exposições ambientais. Agências como a Agência de Proteção Ambiental (EPA) 27 integram a caracterização de uma exposição com efeitos ecológicos para determinar os riscos do uso de pesticidas. Os três herbicidas mais usados na Colômbia são glifosato, propanil e glufosinato de amônio. Embora o glifosato tenha sido considerado um herbicida ambientalmente correto desde o início da década de 1970, foi evidenciado por estudos iniciados na década de 1990 que aplicações inadvertidas em pântanos podem ser fatais para larvas de anfíbios. Embora as formulações de glifosato sejam tipicamente consideradas moderadamente tóxicas (CL50 = 1-10 ppm) para a maioria dos organismos aquáticos, para muitas espécies de anfíbios elas são altamente tóxicas (CL50 ˂ 1 ppm). Essa preocupação é agravada pelo fato de que a Colômbia tem uma diversidade incrivelmente alta de anfíbios (791 espécies). Além disso, foi demonstrado que exposições crônicas de algumas espécies de anfíbios a concentrações subletais, que são mais prováveis no ambiente, causam diminuição da sobrevivência, gônadas intersex, dano na cauda, prolongamento do tempo até a metamorfose e lipidose hepática. Na Colômbia, aplicações aéreas de Glyphos-Cosmo-Flux têm sido usadas desde 1997 para fumigar plantações ilícitas de coca. Em 2019, a Lista Vermelha da União Internacional para a Conservação da Natureza (IUCN) tinha 285 espécies de anfíbios na Colômbia consideradas ameaçadas. Descobrimos que 132 das espécies de anfíbios em perigo (EN) e criticamente em perigo (CR) estavam presentes em 11 dos 32 departamentos colombianos onde há mais plantações ilegais de coca. Portanto, são necessários estudos para avaliar o impacto do programa de erradicação da coca na população de anfíbios do país. O propanil é o principal herbicida usado nos campos de arroz. Apesar de sua rápida degradação ambiental ((1 dia em condições aeróbicas), resumen está disponible en el texto completo

Introduction. Certain naturally derived substances may have herbicidal activity on some weeds species. Objective. To evaluate the efficacy of three substances of natural origin for the control of four weed species and to compare it with the effect of a synthetic broad-spectrum herbicide. Materials and methods. In February 2017, an experiment was conducted in a greenhouse at the Fabio Baudrit Moreno Agricultural Experiment Station, Universidad de Costa Rica. Three commercial products of natural origin based on: 55 % d-limonene, 15% pine extract (Pinus sp.) and 23% thyme extract (Thymus vulgaris) were evaluated; additionally, a product of synthetic origin, gluphosinate ammonium 14 SL, was evaluated. A none treated check was included. These were sprayed on seedlings of Bidens pilosa, Amaranthus sp., Echinochloa colona and Rottboellia cochinchinensis. Results. The seedlings sprayed with the natural herbicides showed symptoms at two hours, but their final efficacy varied among species. Eight-days after spraying, d-limonene was more effective than all other treatments, showing damage ratings higher than 4.25 in all species. Pine and thyme extracts were not effective on B. pilosa. Pine extract caused greater damage on Amaranthus sp, E. colona, and R. cochinchinensis, while the thyme extract caused greater damage on Amaranthus sp and R. cochinchinensis. The synthetic herbicide gluphosinate showed significant damage on all four species. Conclusions. The commercial products of natural origin used had herbicidal activity on the four weed species tested., Introducción. Ciertas sustancias de origen natural pueden tener actividad herbicida sobre algunas especies de arvenses. Objetivo. Evaluar la eficacia de tres sustancias de origen natural para el control de cuatro especies de arvenses y compararla con el efecto de un herbicida sintético de amplio espectro. Materiales y métodos. En febrero del 2017 se condujo un experimento en un invernadero en la Estación Experimental Agrícola Fabio Baudrit Moreno, de la Universidad de Costa Rica. Se evaluaron tres productos comerciales de origen natural a base de: d-limoneno al 55 %, extracto de pino al 15 % (Pinus sp.) y extracto de tomillo al 23 % (Thymus vulgaris); además, se evaluó un producto de origen sintético, glufosinato de amonio 14 SL. Se incluyó un testigo absoluto. Estos se asperjaron sobre plantas de Bidens pilosa, Amaranthus sp., Echinochloa colona y Rottboellia cochinchinensis. Resultados. Las plantas asperjadas con los herbicidas naturales mostraron síntomas a las dos horas, pero su eficacia final varió entre especies. A los ocho días después de la aspersión el d-limoneno resultó más eficaz que todos los demás tratamientos, mostró grados de daño mayores a 4,25 en todas las especies. Con el extracto de pino y el extracto de tomillo no se obtuvo eficacia sobre B. pilosa. El extracto de pino causó mayores daños en Amaranthus sp, E. colona y R. cochinchinensis, mientras que el extracto de tomillo en Amaranthus sp y R. cochinchinensis. El herbicida sintético glufosinato mostró daños significativos en las cuatro especies. Conclusiones. Los productos comerciales de origen natural utilizados, tuvieron actividad herbicida sobre las cuatro especies de arvenses evaluadas.