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Grant C. Hose - One of the best experts on this subject based on the ideXlab platform.
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the ecological effects of a herbicide insecticide mixture on an experimental freshwater ecosystem
Environmental Pollution, 2013Co-Authors: Catherine B Choung, Ross V Hyne, Mark M. Stevens, Grant C. HoseAbstract:Abstract The effects of a co-occurring insecticide–herbicide mixture were evaluated using model ecosystems (microcosms) in the laboratory. Microcosms dosed with a high concentration (10 μg/L) of the insecticide Terbufos, alone and as a mixture with the herbicide atrazine (25 μg/L), exhibited community level effects attributed to the elimination and decline of invertebrate populations, and also indirect effects. There were no community level effects at a lower concentration of Terbufos (0.1 μg/L) alone or in a mixture with atrazine, although delayed population effects were observed. Female chironomids also emerged later and those from Terbufos-only microcosms were smaller. Exposure to atrazine alone was also associated with lower abundances of cladocerans and reduced emergence of chironomids. The risk posed by atrazine is low and is unlikely to exacerbate the effects of Terbufos. Nevertheless, the population-level effects highlight that Terbufos poses a potential risk to aquatic ecosystems, regardless of whether atrazine is also present.
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Toxicity of the Insecticide Terbufos, its Oxidation Metabolites, and the Herbicide Atrazine in Binary Mixtures to Ceriodaphnia cf dubia
Archives of Environmental Contamination and Toxicology, 2011Co-Authors: Catherine B Choung, Ross V Hyne, Mark M. Stevens, Grant C. HoseAbstract:The acute toxicity of Terbufos and its major metabolites, tested alone, in binary mixtures or in combination with atrazine were evaluated using neonates of the cladoceran Ceriodaphnia cf dubia . Terbufos, Terbufos sulfoxide, and Terbufos sulfone tested individually were highly toxic to C. cf dubia , with mean 96-h EC_50 values of 0.08, 0.36, and 0.19 μg/l, respectively. The addition of atrazine (10 μg/l) significantly increased the toxicity of Terbufos. The toxicity of Terbufos sulfone was unaffected by atrazine, whereas the results for Terbufos sulfoxide were equivocal. Equitoxic mixtures of the metabolites showed additive toxicity to C. cf dubia . The high toxicities of Terbufos and its environmentally persistent oxidative metabolites suggest that contamination of aquatic systems with this insecticide mixture and the coapplied herbicide atrazine might pose a greater hazard to some biota than their individual toxicities.
Hose, Grant C - One of the best experts on this subject based on the ideXlab platform.
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The Ecological effects of a herbicide-insecticide mixture on an experimental freshwater ecosystem
'Elsevier BV', 2013Co-Authors: Choung, Catherine B, Hyne Ross, Stevens, Mark M, Hose, Grant CAbstract:The effects of a co-occurring insecticide-herbicide mixture were evaluated using model ecosystems (microcosms) in the laboratory. Microcosms dosed with a high concentration (10 μg/L) of the insecticide Terbufos, alone and as a mixture with the herbicide atrazine (25 μg/L), exhibited community level effects attributed to the elimination and decline of invertebrate populations, and also indirect effects. There were no community level effects at a lower concentration of Terbufos (0.1 μg/L) alone or in a mixture with atrazine, although delayed population effects were observed. Female chironomids also emerged later and those from Terbufos-only microcosms were smaller. Exposure to atrazine alone was also associated with lower abundances of cladocerans and reduced emergence of chironomids. The risk posed by atrazine is low and is unlikely to exacerbate the effects of Terbufos. Nevertheless, the population-level effects highlight that Terbufos poses a potential risk to aquatic ecosystems, regardless of whether atrazine is also present.11 page(s
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Developmental toxicity of two common corn pesticides to the endangered southern bell frog (Litoria raniformis)
'Elsevier BV', 2011Co-Authors: Choung, Catherine B, Hyne Ross, Stevens, Mark M, Mann, Reinier M, Hose, Grant CAbstract:To examine the link between corn agriculture and the observed decline of the endangered southern bell frog (SBF), the effects of two corn crop pesticides on larval growth and development were investigated. Tadpoles were exposed to Terbufos sulfone (10 μg/L), a major breakdown product of the insecticide Terbufos, and the herbicide atrazine (25 μg/L) individually and as a mixture until the completion of metamorphosis. Atrazine did not interact synergistically with Terbufos sulfone or result in significant effects on growth and development alone, although there was some indication of accelerated metamorphosis in the pilot study. Terbufos sulfone alone and as a mixture (Terbufos/atrazine) significantly slowed larval development and ultimately delayed metamorphosis. The observed developmental effects from an environmentally relevant concentration of Terbufos sulfone indicates a risk posed by this persistent degradation product to the endangered SBF, which breeds and develops in the rice bays adjacent to corn fields treated with pesticides.8 page(s
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Toxicity of the insecticide Terbufos, its oxidation metabolites, and the herbicide atrazine in binary mixtures to ceriodaphnia cf dubia
'Springer Science and Business Media LLC', 2011Co-Authors: Choung, Catherine B, Hyne Ross, Stevens, Mark M, Hose, Grant CAbstract:The acute toxicity of Terbufos and its major metabolites, tested alone, in binary mixtures or in combination with atrazine were evaluated using neonates of the cladoceran Ceriodaphnia cf dubia. Terbufos, Terbufos sulfoxide, and Terbufos sulfone tested individually were highly toxic to C. cf dubia, with mean 96-h EC50 values of 0.08, 0.36, and 0.19 μg/l, respectively. The addition of atrazine (10 μg/l) significantly increased the toxicity of Terbufos. The toxicity of Terbufos sulfone was unaffected by atrazine, whereas the results for Terbufos sulfoxide were equivocal. Equitoxic mixtures of the metabolites showed additive toxicity to C. cf dubia. The high toxicities of Terbufos and its environmentally persistent oxidative metabolites suggest that contamination of aquatic systems with this insecticide mixture and the coapplied herbicide atrazine might pose a greater hazard to some biota than their individual toxicities.9 page(s
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A Low concentration of atrazine does not influence the acute toxicity of the insecticide Terbufos or its breakdown products to Chironomus tepperi
'Springer Science and Business Media LLC', 2010Co-Authors: Choung, Catherine B, Hyne Ross, Stevens, Mark M, Hose, Grant CAbstract:The acute toxicities of the insecticide Terbufos and its major breakdown products individually, as binary mixtures, and in combination with the co-applied herbicide atrazine were evaluated using final instar larvae of the midge Chironomus tepperi. Terbufos, Terbufos sulfoxide and Terbufos sulfone were highly toxic to C. tepperi with mean 96-h EC50 values of 2.13, 3.64 and 2.59 μg/l, respectively. No interaction was observed between atrazine (25 μg/l) and Terbufos or its breakdown products while the binary mixture of Terbufos sulfoxide and Terbufos sulfone exhibited additive toxicity. The high toxicities of Terbufos and its environmentally persistent oxidation products suggest that contamination of aquatic systems with this insecticide pose a threat to aquatic organisms whether or not atrazine is also present.9 page(s
Catherine B Choung - One of the best experts on this subject based on the ideXlab platform.
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the ecological effects of a herbicide insecticide mixture on an experimental freshwater ecosystem
Environmental Pollution, 2013Co-Authors: Catherine B Choung, Ross V Hyne, Mark M. Stevens, Grant C. HoseAbstract:Abstract The effects of a co-occurring insecticide–herbicide mixture were evaluated using model ecosystems (microcosms) in the laboratory. Microcosms dosed with a high concentration (10 μg/L) of the insecticide Terbufos, alone and as a mixture with the herbicide atrazine (25 μg/L), exhibited community level effects attributed to the elimination and decline of invertebrate populations, and also indirect effects. There were no community level effects at a lower concentration of Terbufos (0.1 μg/L) alone or in a mixture with atrazine, although delayed population effects were observed. Female chironomids also emerged later and those from Terbufos-only microcosms were smaller. Exposure to atrazine alone was also associated with lower abundances of cladocerans and reduced emergence of chironomids. The risk posed by atrazine is low and is unlikely to exacerbate the effects of Terbufos. Nevertheless, the population-level effects highlight that Terbufos poses a potential risk to aquatic ecosystems, regardless of whether atrazine is also present.
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Toxicity of the Insecticide Terbufos, its Oxidation Metabolites, and the Herbicide Atrazine in Binary Mixtures to Ceriodaphnia cf dubia
Archives of Environmental Contamination and Toxicology, 2011Co-Authors: Catherine B Choung, Ross V Hyne, Mark M. Stevens, Grant C. HoseAbstract:The acute toxicity of Terbufos and its major metabolites, tested alone, in binary mixtures or in combination with atrazine were evaluated using neonates of the cladoceran Ceriodaphnia cf dubia . Terbufos, Terbufos sulfoxide, and Terbufos sulfone tested individually were highly toxic to C. cf dubia , with mean 96-h EC_50 values of 0.08, 0.36, and 0.19 μg/l, respectively. The addition of atrazine (10 μg/l) significantly increased the toxicity of Terbufos. The toxicity of Terbufos sulfone was unaffected by atrazine, whereas the results for Terbufos sulfoxide were equivocal. Equitoxic mixtures of the metabolites showed additive toxicity to C. cf dubia . The high toxicities of Terbufos and its environmentally persistent oxidative metabolites suggest that contamination of aquatic systems with this insecticide mixture and the coapplied herbicide atrazine might pose a greater hazard to some biota than their individual toxicities.
Denis J. Wright - One of the best experts on this subject based on the ideXlab platform.
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Sub-lethal effects of tefluthrin on Diabrotica undecimpunctata howardi, Barber: plant protection and larval development
Crop Protection, 1997Co-Authors: Paris K. Michaelides, Ann L. Cleverly, Denis J. WrightAbstract:Abstract Larval stages of the southern corn rootworm, Diabrotica undecimpunctata howardi (Barber) (Coleoptera: Chrysomelidae), were used to assess the effects of sub-lethal concentrations of the soil insecticides tefluthrin and Terbufos. It was shown that significant plant protection was only possible with high (LC80) levels of Terbufos, whilst protection was achieved with much lower (LC20) concentrations of tefluthrin. This protection was achieved by anorectic, poisoning effects of the pesticides on the larvae. Unlike tefluthrin, Terbufos did not affect feeding activity at sub-lethal levels and a high level of pest mortality was required for comparable protection. The reduced feeding of the tefluthrintreated larvae also led to lower larval and adult weights and lower survival to adulthood when compared with controls.
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Insecticide Penetration and Symptomology Studies on Larvae of Diabrotica undecimpunctata howardi (Barber)
Pesticide Science, 1997Co-Authors: Paris K. Michaelides, Denis J. WrightAbstract:The internal and external levels of topically applied soil insecticides, tefluthrin, Terbufos and dieldrin, to 3rd-instar larvae of the southern corn rootworm, Diabrotica undecimpunctata howardi (Barber), were monitored over 48 h. Symptomology of poisoning with 10 times the dose of the larval 72-h LD 90 for each chemical was observed over 48 h at various time points after treatment. Terbufos penetrated more rapidly than tefluthrin or dieldrin, although internal levels of tefluthrin and dieldrin had a longer-lasting plateau than Terbufos. A 72-h LD 3O treatment with tefluthrin resulted in faster penetration and also faster disappearance from the insect compared with the 10 x 72-h LD 90 dose over a 48-h period. Recorded symptoms of poisoning included regurgitation of gut contents, defaecation and writhing and these are suggested to play an important part in voiding of the toxicants at lower (sub-lethal) treatment levels. The sub-lethal effects of tefluthrin are discussed with respect to likely pest behavioural changes, such as anorectic response, after field treatment of a crop.
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Activity of soil insecticides on eggs of Diabrotica undecimpunctata howardi : Effects on embryological development and influence of egg age
Pesticide Science, 1997Co-Authors: Paris K. Michaelides, Denis J. WrightAbstract:The activity of tefluthrin, carbofuran, Terbufos and dieldrin in soil against eggs of different ages of the southern corn rootworm, Diabrotica undecimpunctata howardi (Barber) (Coleoptera: Chrysomelidae) was determined. Embryological development following treatment with these insecticides was also investigated to determine the stage of developmental arrest. Generally, younger eggs were found to be more susceptible, dieldrin being the least and tefluthrin the most potent ovicide of combined egg age mortalities. Terbufos and carbofuran were relatively inactive against older eggs compared with tefluthrin. Terbufos stopped embryonic development at the time when acetylcholine esterase activity has been shown to commence. Carbofuran, dieldrin and tefluthrin slowed but did not arrest embryonic development, although the two former compounds prevented eclosion to a greater degree than tefluthrin, suggesting death during absorption of serosal fluids at eclosion. Neonate emergence following treatment of eggs with tefluthrin resulted in death within a few hours. The results are discussed in relation to insecticidal action and permeability changes of egg membrane structure with age. © 1997 SCI.
Mark M. Stevens - One of the best experts on this subject based on the ideXlab platform.
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the ecological effects of a herbicide insecticide mixture on an experimental freshwater ecosystem
Environmental Pollution, 2013Co-Authors: Catherine B Choung, Ross V Hyne, Mark M. Stevens, Grant C. HoseAbstract:Abstract The effects of a co-occurring insecticide–herbicide mixture were evaluated using model ecosystems (microcosms) in the laboratory. Microcosms dosed with a high concentration (10 μg/L) of the insecticide Terbufos, alone and as a mixture with the herbicide atrazine (25 μg/L), exhibited community level effects attributed to the elimination and decline of invertebrate populations, and also indirect effects. There were no community level effects at a lower concentration of Terbufos (0.1 μg/L) alone or in a mixture with atrazine, although delayed population effects were observed. Female chironomids also emerged later and those from Terbufos-only microcosms were smaller. Exposure to atrazine alone was also associated with lower abundances of cladocerans and reduced emergence of chironomids. The risk posed by atrazine is low and is unlikely to exacerbate the effects of Terbufos. Nevertheless, the population-level effects highlight that Terbufos poses a potential risk to aquatic ecosystems, regardless of whether atrazine is also present.
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Toxicity of the Insecticide Terbufos, its Oxidation Metabolites, and the Herbicide Atrazine in Binary Mixtures to Ceriodaphnia cf dubia
Archives of Environmental Contamination and Toxicology, 2011Co-Authors: Catherine B Choung, Ross V Hyne, Mark M. Stevens, Grant C. HoseAbstract:The acute toxicity of Terbufos and its major metabolites, tested alone, in binary mixtures or in combination with atrazine were evaluated using neonates of the cladoceran Ceriodaphnia cf dubia . Terbufos, Terbufos sulfoxide, and Terbufos sulfone tested individually were highly toxic to C. cf dubia , with mean 96-h EC_50 values of 0.08, 0.36, and 0.19 μg/l, respectively. The addition of atrazine (10 μg/l) significantly increased the toxicity of Terbufos. The toxicity of Terbufos sulfone was unaffected by atrazine, whereas the results for Terbufos sulfoxide were equivocal. Equitoxic mixtures of the metabolites showed additive toxicity to C. cf dubia . The high toxicities of Terbufos and its environmentally persistent oxidative metabolites suggest that contamination of aquatic systems with this insecticide mixture and the coapplied herbicide atrazine might pose a greater hazard to some biota than their individual toxicities.
