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ASSESSING AND MITIGATING LAWN INSECTICIDE HAZARDS TO BEES AND OTHER BENEFICIAL INVERTEBRATESLarson, Jonathan Lane 01 January 2014 (has links)
Turfgrass settings, including lawns, golf courses, and sports fields, support many beneficial invertebrates that provide important ecosystem services. These non-target organisms and their associated predation, decomposition, and pollination services can be disrupted by the use of certain insecticides. I compared the ecotoxicity of representatives from three major turf insecticide groups, the neonicotinoids, premix formulations, and the anthranilic diamides, in lab and field realistic settings in order to inform industry initiatives towards environmental sustainability.
In lab and field bioassays clothianidin, a neonicotinoid, and a premix clothianidin/pyrethroid spray were acutely toxic to beneficial insects. Populations of predators, springtails, and earthworms, as well as parasitism, predation, and decomposition rates were all reduced. In contrast, chlorantraniliprole, a novel anthranilic diamide with a similar spectrum of pests controlled, had no apparent impact on natural enemies, decomposers, or ecosystem services. This newer class is a good fit for industry initiatives to use relatively less toxic pesticides, with the caveat that golf course superintendents may see secondary pest outbreaks of ants and earthworms.
Bumble bee colonies exposed to clothianidin-treated white clover for two weeks suffered acute effects including increased mortality of workers and decreases in the number of honeypots constructed in the hive. When hives were exposed to clothianidin treated clover for six days and then allowed to develop naturally over six weeks they exhibited delayed weight gain and produced no new queens. Colonies exposed to chlorantraniliprole-treated flowers suffered no observable adverse effects. When treated blooms were mowed, colonies exposed to newly-formed blooms exhibited no ill effects. After a single mowing neonicotinoid residues in clover nectar were reduced from > 2000 ng/g, to < 10 ng/g. Residues of imidacloprid were also short-lived in guttation water.
Some 50 species of bees and other pollinators were collected from flowering white clover and dandelions in lawns across an urbanization gradient. Such weeds, an underappreciated resource for urban bees, could play a role in pollinator conservation if tolerated and not over-sprayed with broad-spectrum insecticides. Informing the public about the potential benefits these weeds could have for pollinators may help lead to more environmentally conscious management decisions.
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Impact of Simulated Corn Earworm Damage on Field Corn Yield and the Influence of Chlorantraniliprole and Flubendiamide on Fall Armyworm and Agronomic Characteristics of Field CornOlivi, Bryan Michael 09 December 2016 (has links)
The introduction of pyramided Bacillus thuringinesiss (Bt) in field corn, Zea mays L. has helped reduce kernel and foliar damage from caterpillar pests including fall armyworm, Spodoptera frugiperda (J.E. Smith) and corn earworm, Helicoverpa zea (Boddie). These pests can also be controlled with diamide insecticides. No compensation for manual kernel damage occurred at any section of the ear for Bt or Non-Bt corn. No consistent impacts on corn growth or yield were observed following foliar applications of diamide insecticides at various growth stages. The diamides exhibit longer residual efficacy than other insecticides available for fall armyworm management in field corn. Based on the level of mortality observed on young tissue developed after treatment with chlorantraniliprole, chlorantraniliprole translocated in corn and could therefore be more beneficial than other insecticides when applied during vegetative growth stages.
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Monitoramento da suscetibilidade de populações de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) a inseticidas diamidas no Brasil / Monitoring the susceptibility to diamide insecticides in Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) populations in BrazilRibeiro, Rebeca da Silva 09 October 2014 (has links)
Spodoptera frugiperda (J.E. Smith) é uma das pragas mais importantes da cultura do milho no Brasil. Vários casos de resistência de S. frugiperda a inseticidas de grupos químicos distintos já foram documentados. A busca contínua de alternativas para o controle de S. frugiperda tem possibilitado o desenvolvimento de novas tecnologias como plantas de milho geneticamente modificadas, e até mesmo a introdução de inseticidas que aliam segurança ambiental e alta atividade inseticida, como o recente grupo das diamidas. Estudos de caracterização e monitoramento da suscetibilidade de S. frugiperda são fundamentais para a implementação de programas de Manejo da Resistência de Insetos (MRI) no Brasil. Com o intuito de se prolongar a vida útil das diamidas, os objetivos deste trabalho foram: (a) caracterizar a suscetibilidade a diamidas em populações de S. frugiperda nas principais regiões produtoras de milho no Brasil na safra 2011/12; (b) monitorar a suscetibilidade de populações de S. frugiperda a chlorantraniliprole e flubendiamide coletadas na cultura do milho em oito estados do Brasil nas safras 2011/12, 2012/13 e 2013/14; (c) estimar a frequência inicial do alelo de resistência a chlorantraniliprole em populações de S. frugiperda. O método de bioensaio para a caracterização da suscetibilidade de populações de S. frugiperda a chlorantraniliprole e flubendiamide foi o de aplicação superficial do inseticida sobre a dieta. As linhas-básicas de suscetibilidade foram definidas para uma população suscetível de referência e cinco populações de campo de S. frugiperda. Posteriormente, foram definidas concentrações diagnósticas para o monitoramento da suscetibilidade para ambos inseticidas em populações de S. frugiperda. As CLs50 estimadas para as populações de S. frugiperda avaliadas variaram de 1,15 a 2,55 ?g de chlorantraniliprole/mL de água [I.A. (ppm)] (variação de 1,4 vezes), e de 1,75 a 4,17 ?g de flubendiamide/mL de água [I.A. (ppm)] (variação de 2,4 vezes). As concentrações diagnósticas de 10 e 32 ?g de chlorantraniliprole/mL e de 100 e 180?g de flubendiamide/mL foram definidas para o monitoramento da resistência. As populações de S. frugiperda apresentaram alta suscetibilidade nas concentrações diagnósticas de chlorantraniliprole e flubendiamide na safra 2011/12. No entanto, foram observadas variações na sobrevivência de 0 a 12,7% para chlorantraniliprole e de 1 a 6% para flubendiamide de acordo com a safra agrícola e localidade. A frequência do alelo resistente a chlorantraniliprole em S. frugiperda estimado pelo método de \"F2 Screen\" foi baixa para a safra 2011/12 (<0,0033). No entanto, aumento significativo na frequência do alelo resistente foi observado nas safras 2012/13 [0,0134 (0,0082 - 0,0198)] e 2013/14 [0,0176 (0,0084 - 0,0277)] em populações testadas, indicando alto risco de evolução da resistência a chlorantraniliprole no Brasil. / Spodoptera frugiperda (J.E. Smith) is one of the most important maize pests in Brazil. Several cases of S. frugiperda resistance to insecticides of different chemical class have been documented. The continuous search for alternatives to control S. frugiperda has enabled the development of new technologies such as genetically modified corn plants, and even the introduction of insecticides that combine environmental safety and high insecticidal activity, such as the recent class of diamides. Baseline studies and monitoring the susceptibility of S. frugiperda to insecticides are fundamental to the implementation of Insect Resistance Management (IRM) programs in Brazil. In order to prolong the lifetime of diamides, the objectives of this work were: (a) characterize the susceptibility to diamides in populations of S. frugiperda collected from major corn-producing regions in Brazil in 2011/12 season; (b) monitor the susceptibility of S. frugiperda populations to chlorantraniliprole and flubendiamide collected in maize in eight states of Brazil in the 2011/12, 2012/13 and 2013/14 growing seasons; (c) estimate the initial frequency of the allele for resistance to chlorantraniliprole in S. frugiperda populations. The baseline susceptibility of S. frugiperda populations to chlorantraniliprole and flubendiamide was determined using the diet surface treatment bioassays. Baselines were defined for a susceptible population and five field populations of S. frugiperda. Subsequently, diagnostic concentrations for monitoring susceptibility to both insecticides were defined. LCs50 estimated for populations of S. frugiperda ranged from 1.15 to 2.55 mg of chlorantraniliprole / mL of water [IA (ppm)] (1.4-fold variation) and 1.75 to 4.17 mg of flubendiamide / ml water [IA (ppm)] (2.4-fold variation). The diagnostic concentrations of 10 and 32 mg of chlorantraniliprole / mL and 100 and 180?g of flubendiamide / mL were defined for the resistance monitoring. The populations of S. frugiperda showed high susceptibility to chlorantraniliprole and flubendiamide in 2011/12 growing season at diagnostic concentrations. However, variations in survival from 0 to 12.7% for chlorantraniliprole and 1 to 6% for flubendiamide were observed based on growing season and location. The frequency of the resistant allele to chlorantraniliprole in S. frugiperda estimated by using \"F2 Screen\" method was low during 2011/12 growing season (<0.0033). However, significant increase in the frequency of the resistant allele was observed in 2012/13 [0.0134 (0.0082 to 0.0198)] and 2013-14 [0.0176 (0.0084 to 0.0277)] growing seasons, indicating a high risk of resistance evolution to chlorantraniliprole in Brazil.
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Monitoramento da suscetibilidade de populações de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) a inseticidas diamidas no Brasil / Monitoring the susceptibility to diamide insecticides in Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) populations in BrazilRebeca da Silva Ribeiro 09 October 2014 (has links)
Spodoptera frugiperda (J.E. Smith) é uma das pragas mais importantes da cultura do milho no Brasil. Vários casos de resistência de S. frugiperda a inseticidas de grupos químicos distintos já foram documentados. A busca contínua de alternativas para o controle de S. frugiperda tem possibilitado o desenvolvimento de novas tecnologias como plantas de milho geneticamente modificadas, e até mesmo a introdução de inseticidas que aliam segurança ambiental e alta atividade inseticida, como o recente grupo das diamidas. Estudos de caracterização e monitoramento da suscetibilidade de S. frugiperda são fundamentais para a implementação de programas de Manejo da Resistência de Insetos (MRI) no Brasil. Com o intuito de se prolongar a vida útil das diamidas, os objetivos deste trabalho foram: (a) caracterizar a suscetibilidade a diamidas em populações de S. frugiperda nas principais regiões produtoras de milho no Brasil na safra 2011/12; (b) monitorar a suscetibilidade de populações de S. frugiperda a chlorantraniliprole e flubendiamide coletadas na cultura do milho em oito estados do Brasil nas safras 2011/12, 2012/13 e 2013/14; (c) estimar a frequência inicial do alelo de resistência a chlorantraniliprole em populações de S. frugiperda. O método de bioensaio para a caracterização da suscetibilidade de populações de S. frugiperda a chlorantraniliprole e flubendiamide foi o de aplicação superficial do inseticida sobre a dieta. As linhas-básicas de suscetibilidade foram definidas para uma população suscetível de referência e cinco populações de campo de S. frugiperda. Posteriormente, foram definidas concentrações diagnósticas para o monitoramento da suscetibilidade para ambos inseticidas em populações de S. frugiperda. As CLs50 estimadas para as populações de S. frugiperda avaliadas variaram de 1,15 a 2,55 ?g de chlorantraniliprole/mL de água [I.A. (ppm)] (variação de 1,4 vezes), e de 1,75 a 4,17 ?g de flubendiamide/mL de água [I.A. (ppm)] (variação de 2,4 vezes). As concentrações diagnósticas de 10 e 32 ?g de chlorantraniliprole/mL e de 100 e 180?g de flubendiamide/mL foram definidas para o monitoramento da resistência. As populações de S. frugiperda apresentaram alta suscetibilidade nas concentrações diagnósticas de chlorantraniliprole e flubendiamide na safra 2011/12. No entanto, foram observadas variações na sobrevivência de 0 a 12,7% para chlorantraniliprole e de 1 a 6% para flubendiamide de acordo com a safra agrícola e localidade. A frequência do alelo resistente a chlorantraniliprole em S. frugiperda estimado pelo método de \"F2 Screen\" foi baixa para a safra 2011/12 (<0,0033). No entanto, aumento significativo na frequência do alelo resistente foi observado nas safras 2012/13 [0,0134 (0,0082 - 0,0198)] e 2013/14 [0,0176 (0,0084 - 0,0277)] em populações testadas, indicando alto risco de evolução da resistência a chlorantraniliprole no Brasil. / Spodoptera frugiperda (J.E. Smith) is one of the most important maize pests in Brazil. Several cases of S. frugiperda resistance to insecticides of different chemical class have been documented. The continuous search for alternatives to control S. frugiperda has enabled the development of new technologies such as genetically modified corn plants, and even the introduction of insecticides that combine environmental safety and high insecticidal activity, such as the recent class of diamides. Baseline studies and monitoring the susceptibility of S. frugiperda to insecticides are fundamental to the implementation of Insect Resistance Management (IRM) programs in Brazil. In order to prolong the lifetime of diamides, the objectives of this work were: (a) characterize the susceptibility to diamides in populations of S. frugiperda collected from major corn-producing regions in Brazil in 2011/12 season; (b) monitor the susceptibility of S. frugiperda populations to chlorantraniliprole and flubendiamide collected in maize in eight states of Brazil in the 2011/12, 2012/13 and 2013/14 growing seasons; (c) estimate the initial frequency of the allele for resistance to chlorantraniliprole in S. frugiperda populations. The baseline susceptibility of S. frugiperda populations to chlorantraniliprole and flubendiamide was determined using the diet surface treatment bioassays. Baselines were defined for a susceptible population and five field populations of S. frugiperda. Subsequently, diagnostic concentrations for monitoring susceptibility to both insecticides were defined. LCs50 estimated for populations of S. frugiperda ranged from 1.15 to 2.55 mg of chlorantraniliprole / mL of water [IA (ppm)] (1.4-fold variation) and 1.75 to 4.17 mg of flubendiamide / ml water [IA (ppm)] (2.4-fold variation). The diagnostic concentrations of 10 and 32 mg of chlorantraniliprole / mL and 100 and 180?g of flubendiamide / mL were defined for the resistance monitoring. The populations of S. frugiperda showed high susceptibility to chlorantraniliprole and flubendiamide in 2011/12 growing season at diagnostic concentrations. However, variations in survival from 0 to 12.7% for chlorantraniliprole and 1 to 6% for flubendiamide were observed based on growing season and location. The frequency of the resistant allele to chlorantraniliprole in S. frugiperda estimated by using \"F2 Screen\" method was low during 2011/12 growing season (<0.0033). However, significant increase in the frequency of the resistant allele was observed in 2012/13 [0.0134 (0.0082 to 0.0198)] and 2013-14 [0.0176 (0.0084 to 0.0277)] growing seasons, indicating a high risk of resistance evolution to chlorantraniliprole in Brazil.
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Monitoramento e caracterização da resistência de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) a inseticidas diamidas no Brasil / Monitoring and characterization of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) resistance to diamide insecticides in BrazilBolzan, Anderson 10 June 2019 (has links)
O controle de Spodoptera frugiperda (J. E. Smith) tem sido realizado principalmente pelo uso de inseticidas químicos e plantas geneticamente modificadas que expressam toxinas de Bacillus thuringiensis Berliner (Bt) no Brasil. Casos de evolução da resistência no campo a estes agentes de controle têm sido uma das grandes ameaças para programas de MIP. Inseticidas diamidas ainda representam uma importante opção para o manejo de S. frugiperda; sendo assim, estudos que fomentem a implementação de estratégias pró-ativas de manejo da resistência são fundamentais para a manutenção da eficácia deste grupo químico no controle de S. frugiperda. Os objetivos da presente tese foram: (i) Monitorar a resistência de S. frugiperda a inseticidas diamidas no Brasil, utilizando métodos genotípico e fenotípico; (ii) Selecionar em laboratório uma linhagem de S. frugiperda resistente a inseticidas diamidas e caracterizar as bases genéticas da resistência; e (iii) Investigar os mecanismos associados à resistência de S. frugiperda a inseticidas diamidas. O método de F2 \"screen\" foi utilizada para o monitoramento genotípico da resistência de S. frugiperda ao inseticida chlorantraniliprole, sendo testadas 817 isolinhas provenientes de 14 populações brasileiras de S. frugiperda entre os anos agrícolas 2016 e 2017. Dentre as populações testadas, foi verificada uma variação de 0,0030 a 0,0781 na frequência de alelos que conferem resistência a chlorantraniliprole, com média geral de 0,0217. No monitoramento fenotípico, foram testadas ≈ 70 populações de S. frugiperda coletadas das principais regiões produtoras de milho durante os anos agrícolas 2016, 2017 e 2018. A sobrevivência larval para o inseticida chlorantraniliprole variou de 0,00 a 32,08% na concentração diagnóstica de 0,505 µg de chlorantraniliprole cm-2. Para o inseticida flubendiamide, as sobrevivências variaram de 0,00 a 46,25% na concentração diagnóstica de 2,842 µg de flubendiamide cm-2. Populações de S. frugiperda da Bahia, Mato Grosso, Mato Grosso do Sul e Goiás apresentaram as menores suscetibilidades a chlorantraniliprole e flubendiamide. Os valores de CL50 das linhagens suscetível (Sus) e resistente a chlorantraniliprole (Chlorant-R) foram 0,011 e 2,610 µg i.a.cm-2, respectivamente, com razão de resistência (RR) de ≈ 240 vezes. A herança da resistência de S. frugiperda a chlrontraniliprole foi caracterizada como autossômica, incompletamente recessiva e monogênica. A linhagem resistente a chlorantraniliprole apresentou moderada resistência cruzada para cyantraniliprole (RR ≈ 27 vezes) e muito alta para flubendiamide (RR > 42000 vezes). A pré-exposição a diferentes sinergistas inibidores de enzimas de detoxificação não aumentou significativamente a suscetibilidade larval, sugerindo que a resistência metabólica não está envolvida na resistência de S. frugiperda a diamidas. Mediante sequenciamento da região C-terminal dos receptores de rianodina (RyR) nos domínios II a IV, foi detectada a mutação I4734M que foi recentemente descrita como um dos mecanismos de resistência devido à alteração no alvo de ação de inseticidas diamidas em outras pragas de Lepidoptera. Os resultados obtidos no presente trabalho servirão para a implementação de estratégias efetivas de manejo da resistência para preservar a vida útil de diamidas para o manejo de S. frugiperda no Brasil. / The control of Spodoptera frugiperda (J. E. Smith) has been performed mainly by the use of insecticides and genetically modified plants expressing Bacillus thuringiensis Berliner (Bt) toxins in Brazil. Field-evolved resistance to these control agents represents a major threat in IPM programs. Diamide insecticides represent an important tool for managing S. frugiperda; therefore, studies that promote proactive resistance management strategies are important to prolong the lifetime of this chemical group to control S. frugiperda. The goals of this dissertation were: (i) To monitor S. frugiperda resistance to diamide insecticides in Brazil, using genotypic and phenotypic methods; (ii) To select a resistant strain of S. frugiperda to diamide insecticides under laboratory conditions and to characterize the genetic basis of resistance; and (iii) to investigate the resistance mechanisms of S. frugiperda to diamides insecticides. The F2 screen method was used to genotypic monitoring of S. frugiperda resistance to chlorantraniliprole resistance by testing 817 isofamilies from 14 Brazilian populations of S. frugiperda collected in 2016 and 2017 crop seasons. Among the populations tested, resistance allelic frequency to chlorantraniliprole ranged from 0.0030 to 0.0781, with overall average of 0.0217. In the phenotypic monitoring, we monitored ≈ 70 populations of S. frugiperda collected from major maize-growing regions during the crop seasons 2016, 2017 and 2018. The larval survival for chlorantraniliprole insecticide ranged from 0.00 to 32.08% at diagnostic concetration of 0.505 µg chlorantraniliprole cm-2 and 0.00 to 46.25% for flubendiamide at diagnostic concentration of 2.842 µg flubendiamide cm-2. Populations of S. frugiperda from Bahia, Mato Grosso, Mato Grosso do Sul and Goiás showed the lowest susceptibilities to chlorantraniliprole and flubendiamide. The LC50 values of the susceptible (Sus) and chlorantraniliprole-resistant (Chlorant-R) strains were 0.011 and 2.610 µg i.a. cm-2, respectively, with a resistance ratio (RR) of ≈ 240-fold. The inheritance of chlorantraniliprole resistance in S. frugiperda was characterized as autosomal, incompletely recessive and monogenic. The chlorantraniliprole-resistant strain showed moderate cross-resistance to cyantraniliprole (RR ≈ 27-fold) and high cross-resistance to flubendiamide (RR > 42,000-fold). Pre-exposure to different synergists known to inhibit detoxification enzymes did not result in significantly increased larval toxicity, suggesting a minor role of metabolic resistance. Sequencing of the FAW ryanodine receptor (RyR) C-terminal domains II to VI revealed a SNP, resulting in a I4734M mutation recently described to confer target-site resistance to diamides in lepidopteran pests. The results obtained herein will help for the implementation of effective resistance management strategies to preserve the lifetime of diamides to manage S. frugiperda in Brazil.
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Impact of Water Management and Agronomic Practices on the Performance of Insecticide Seed Treatments against Rice Water Weevil, Lissorhoptrus Oryzophilus Kuschel, in Mississippi RiceAdams, Charles Andrew 11 May 2013 (has links)
Two field trials were conducted to determine the impact of water management on the efficacy of insecticide seed treatments against rice water weevil, Lissorhoptrus oryzophilus Kuschel, in rice at the Delta Research and Extension Center during 2011 and 2012. The performance of thiamethoxam, chlorantraniliprole, and clothianidin was evaluated when the permanent flood was established at different timings (6 and 8 weeks after planting) and the effect of flush number (0, 1, or 2) on seed treatment performance was evaluated. Seed treatment efficacy was not impacted by delayed flooding, but 2 flushes reduced efficacy of some seed treatments. Experiments were also conducted to determine the impact of reduced seeding rates found in hybrid rice production on the efficacy of insecticide seed treatments targeting rice water weevil. Efficacy was similar when comparing currently labeled rates of thiamethoxam, chlorantraniliprole, and clothianidin with higher rates of these products.
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Optimisation des marais filtrants pour l’abattement du pesticide chlorantraniliprole du ruissellement agricoleAbas, Khalil 02 1900 (has links)
Au cours des dernières décennies, une grande variété de pesticides émergents, tels que le chlorantraniliprole (CAP), ont été introduits malgré le manque de connaissance approfondie de leur risque écotoxicologique. Les marais filtrants (TW) sont des technologies écologiques et durables qui ont montré un grand potentiel d’atténuation des polluants agricoles communs, tels que les pesticides dans le ruissellement. L’objectif de cette étude était d’optimiser l’utilisation du marais filtrant sous-surfacique à écoulement horizontal (HSSF) en déterminant: a) l'effet d’un amendement de biochar au substrat et b) la performance de trois espèces de macrophytes (Phragmites australis subsp. americanus, Scirpus cyperinus et Sporobolus michauxianus) dans l'abattement du CAP du ruissellement agricole. L'efficacité d'abattement a été calculée en utilisant la méthode du bilan de masse dans des mésocosmes HSSF matures alimentés avec un ruissellement agricole synthétique contenant du CAP pendant une période d'un mois. Les mésocosmes avec l’ajout de biochar se sont avérés très efficaces dans l’abattement du CAP (90 à 99%) et ils le sont restés tout au long de la période expérimentale. Cette efficacité est probablement due à la grande capacité d’adsorption du biochar, bien que ce mécanisme n’ait pas été directement mesuré. En revanche, l'abattement du CAP dans les mésocosmes plantés sans biochar était faible et limité et il n’y avait pas de différence entre les espèces, bien qu’elles aient eu des différences dans leur biomasse aérienne et leur taux d'évapotranspiration (ET). Cependant, les traitements plantés ont agi comme zone tampon, en atténuant la masse du CAP de l'influent et en la libérant lentement dans l'effluent. Le taux d'ET de Scirpus et Phragmites était plus élevé que celui de Sporobolus, ce qui s’est traduit par un meilleur effet tampon. Cette étude suggère que l'ajout de biochar au substrat HSSF TW est prometteur pour l'atténuation du CAP dans le ruissellement agricole, mais leur efficacité à long terme reste à être étudiée. Malgré tout, les TW devraient être utilisés comme un outil complémentaire, dans le cadre d'actions plus larges visant à réduire la pression des polluants sur les écosystèmes aquatiques. / Over the past decades, a wide variety of emergent pesticides, such as chlorantraniliprole (CAP),
have been introduced despite the lack of in-depth knowledge of their ecotoxicological risk.
Treatment wetlands (TWs) are environmentally friendly and sustainable technologies that have
shown great potential to mitigate common agricultural pollutants, such as pesticides in runoff.
The objective of this study was to optimize the use of the horizontal subsurface flow treatment
wetlands (HSSF TWs) by determining a) the effect of biochar amendment to the substrate and b)
the performance of three species of macrophytes (Phragmites australis subsp. americanus,
Scirpus cyperinus and Sporobolus michauxianus) in CAP removal from agricultural runoff. The
removal efficiency was calculated using the mass balance method in mature HSSF mesocosms fed
with synthetic agricultural runoff containing CAP for a period of one month. Mesocosms with the
addition of biochar were very effective in removing CAP (90-99%) and remained so throughout
the experimental period. This efficiency is likely due to the high adsorption capacity of biochar,
although this mechanism has not been directly measured. In contrast, CAP removal in mesocosms
planted without biochar was low and limited and there was no difference between species,
although there were differences in their above-ground biomass and their evapotranspiration (ET)
rate. However, the planted mesocosms acted as buffer zones, reducing the CAP mass of the
influent and slowly releasing it into the discharge. The ET rate of S. cyperinus and P. australis was
higher than that of S. michauxianus, resulting in a better buffering effect. This study suggests that
adding biochar to the HSSF TW substrate is promising for CAP attenuation in agricultural runoff,
but their long-term effectiveness remains to be investigated. Nevertheless, TWs should be used
as a complementary tool, as part of wider actions aimed at reducing the pressure of pollutants
on aquatic ecosystems.
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