42 resultados para Dimethoate


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The fate of eight fungicides (benalaxyl, fenarimol, iprodione, metalaxyl, myclobutanil, procymidone, triadimefon, and vinclozolin) and five insecticides (dimethoate, fenthion, methidathion, parathion methyl, and quinalphos) in wine and its byproducts (cake and lees) during the production of distilled spirits was studied. Among the pesticides studied, only fenthion, quinalphos, and vinclozolin residues were present in the distilled spirits. During wine distillation, respectively 13% and 5% of the initial residues of fenthion and vinclozolin were transferred to the distilled spirit. Low percentages (2% for fenthion and 0.1% for vinclozolin) of these active ingredients (AI) also passed from the lees to the final-distilled spirit, when samples were fortified at 10.1 and 26.1 ppm for fenthion and vinclozolin, respectively. Quinalphos passed only from the lees to the final-distilled spirit in percentages lower than 1% when samples were fortified at the highest concentration (4.6 ppm).

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Residues of three pesticides (dimethoate, parathion, and pyrazophos) in two artichoke cultivars, Masedu and Spinoso sardo, were investigated. The amount of pesticides in artichokes was greatly affected by the head shape. In the case of the calix-shaped Masedu artichoke, the residues in whole heads at commercial ripening were on average about twice higher than those of the pagoda-shaped Spinoso sardo artichoke. In the heart this ratio was 4 to 42 times greater. Residue decay rates were very fast, mainly owing to the dilution effect due to head growth.

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The persistence of three pesticides (fenitrothion, dimethoate, and ziram) in apricots in field conditions and their fate during the drying process were studied. After the treatments, the pesticides showed fast decay rates with pseudo-first-order kinetics and half-lives ranging from 6.9 to 9.9 days. The drying process showed a different effect on residue concentrations in dried apricots: omethoate (metabolite of dimethoate) and ziram residues had almost doubled, while fenitrothion disappeared and dimethoate remained constant.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Na agricultura familiar na Amazônia oriental, em particular no nordeste do Pará, são comuns os cultivos semi-perenes com pesada aplicação de agrotóxicos. Em virtude da ampla utilização desses produtos, principalmente o dimetoato, na microbacia hidrográfica do igarapé Cumaru, município de Igarapé-Açu (PA), foi avaliada a retenção dessa substância em amostras da zona não-saturada em laboratório, verificando-se também a influência do pH e dos teores de argila e de matéria orgânica nesse processo. Entre os diversos agrotóxicos utilizados na área, o dimetoato foi selecionado por apresentar maior potencial de lixiviação, segundo o índice GUS (Groundwater Ubiquity Score). Para a quantificação da retenção do dimetoato nos sedimentos da zona não-saturada foi realizado um experimento de sorção. Este último mostrou que, em termos percentuais, a sorção do dimetoato variou de 2.5% a 36.2% (concentração inicial 20 mg.-1) e de 6.20% a 31.0 % (concentração inicial 10 mg. -1). Esses dados comprovam o elevado potencial de contaminação da água subterrânea por essa substância, devido, principalmente, à sua mobilidade e baixa retenção. Devido ao caráter hidrofóbico do dimetoato, que aumenta a sua afinidade com a matéria orgânica, a quantidade sorvida dessa substância se mostrou diretamente proporcional à de matéria orgânica presente nos sedimentos. O pH exerce efeito contrário a este, ou seja, quanto mais elevado o seu valor, menor é a quantidade de dimetoato sorvida. Em relação à variação do teor e ao tipo de argila, foi observado que esses fatores não influenciam na retenção do dimetoato, sendo esse resultado atribuído ao comportamento não iônico desse agrotóxico.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The knockdown and toxic effects of insecticides of different chemical groups and modes of action registered for citrus in Brazil were investigated for effective control of Bucephalogonia xanthophis, a sharpshooter vector of Xylella fastidiosa in citrus. The active ingredients dimethoate (1.2 mL/1.2L), imidacloprid (0.24 mL/1.2L) and lambda-cyhalothrin (0.24 mL/1.2L), as well as a control (water), were sprayed onto branches of potted-citrus nursery trees to evaluate the effect of residual contact. The insects were confined on sprayed branches by using sleeve cages, in groups of 10 per branch (5 branches/treatment). Lambdacyhalothrin showed a knockdown effect on B. xanthophis (>70% mortality within 2 h of exposure), and the residues were effective for approximately one wk. Imidacloprid, lambdacyhalothrin and dimethoate suppressed the vector populations for up to 3 wk after application, when the insects were exposed to sprayed plants for at least 24 h. In another experiment, 2 neonicotinoid insecticides (thiamethoxam and imidacloprid) were applied by soil drench to potted nursery trees, in order to study their systemic effect, i.e., mortality by ingestion on sharpshooter adults. Thiamethoxam and imidacloprid effectively controlled the vectors at all concentrations tested, when the insects were exposed to treated plants for 24 h (>80% mortality) or 48 h (near 100% mortality). The knockdown effect of thiamethoxam and lambda-cyhalothrin might be particularly important to prevent vector transmission of X. fastidiosa in citrus groves.

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Organophosphate können chronische Lungenerkrankungen und Vergiftungen hervorrufen. Bei der Vergiftung erfolgt eine Immunreaktion, welche noch nicht erforscht ist. In dieser Arbeit wurden Toxizitätsstudien an dendritischen Zellen und einem bronchialen Triple-Kultur-Modell durchgeführt. Dendritische Zellen spielen bei der ersten Immunabwehr in der Lunge eine große Rolle. Aus der Zell-Linie THP-1 und primären Monozyten wurden reife dendritische Zellen differenziert und mittels Durchflusszytometrie und Immunfluoreszenz auf spezifische Zellmarker, wie zum Beispiel CD11c, CD83 oder auch CD209, charakterisiert und etabliert. Durch die Vergiftung der Zellen mit Dimethoat und Chlorpyrifos konnte eine Erhöhung des Zelltodes, die Sekretion von proinflammatorischen Mediatoren, Veränderungen in der Morphologie der Zellen und ein Effekt auf den Proteinkinase-Signalweg festgestellt werden. Spezifische dendritische Zellmarker (CD83, CD209) wurden inhibiert und die Dendriten der Dendritischen Zellen kürzer und beschädigt. Die Schädigung von Chlorpyrifos war erheblich größer, als die bei Dimethoat.rnDie weiteren Toxizitätsstudien wurden an einem bronchialen Triple-Kultur-Modell durchgeführt. Hierzu wurden auf Transwell-Filtermembranen bronchiale Epithelzellen, Fibroblastenzellen und Dendritische Zellen verwendet. Die bronchialen Epithelzellen und Fibroblastenzellen waren hier physiologisch voneinander getrennt, konnten aber durch Poren in der Membran miteinander interagieren. Die Etablierung des Triple-Kultur-Modells erfolgte durch die Untersuchung von Entzündungsprozessen, durch Stimulation mit LPS, TNF-alpha und Interferon-gamma. In der Ko-Kultur konnten Zell-Zell-Kontakt Schädigungen und Erhöhung von proinflammatorischen Markern, wie zum Beispiel IL-1ß, IL-6 oder auch IL-8 gemessen werden. Versuche in der Triple-Kultur zeigten den positiven Effekt von Dendritischen Zellen. Bei höheren Konzentrationsbereichen von Dimethoat und Chlorpyrifos konnte ein Wandern der Zellen zu den geschädigten Zell-Zell-Kontakten nachgewiesen werden. Die Ausschüttung der proinflammatorischen Mediatoren wurde inhibiert, vor allem bei IL-10 war eine deutliche Reduktion, um mehr als 70% messbar. Ebenso konnten Veränderungen in dem Apoptose-Signalblick festgestellt werden. Vor allem anti-apoptotische Proteine wurden nach einer Vergiftung der Triple-Kultur induziert. Interventionsstudien mit Vitamin C zeigten allerdings keinen positiven Effekt.

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Aiming to introduce a multiresidue analysis for the trace detection of pesticide residues belonging to organophosphorus and triazine classes from olive oil samples, a new sample preparation methodology comprising the use of a dual layer of “tailor-made” molecularly imprinted polymers (MIPs) SPE for the simultaneous extraction of both pesticides in a single procedure has been attempted. This work has focused on the implementation of a dual MIP-layer SPE procedure (DL-MISPE) encompassing the use of two MIP layers as specific sorbents. In order to achieve higher recovery rates, the amount of MIP layers has been optimized as well as the influence of MIP packaging order. The optimized DL-MISPE approach has been used in the preconcentration of spiked organic olive oil samples with concentrations of dimethoate and terbuthylazine similar to the maximum residue limits and further quantification by HPLC. High recovery rates for dimethoate (95%) and terbuthylazine (94%) have been achieved with good accuracy and precision. Overall, this work constitutes the first attempt on the development of a dual pesticide residue methodology for the trace analysis of pesticide residues based on molecular imprinting technology. Thus, DL-MISPE constitutes a reliable, robust, and sensitive sample preparation methodology that enables preconcentration of the target pesticides in complex olive oil samples, even at levels similar to the maximum residue limits enforced by the legislation.

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BACKGROUND: Drosophila suzukii is a primary insect pest that causes direct damage to fruits with a thin epidermis such as strawberries, cherries and blueberries. In strawberry fields, the co-occurrence of D. suzukii and Zaprionus indianus has increased production losses. This study evaluated the toxicities and effects of insecticidal baits to control adults and larvae of both D. suzukii and Z. indianus . RESULTS: Organophosphate (dimethoate and malathion), spinosyn (spinosad and spinetoram), pyrethroid (lambda-cyhalothrin) and diamide (cyantraniliprole) insecticides exhibited high toxicity to both adults and larvae of D. suzukii and Z. indianus (mortality > 80%) in topical and dip bioassays. However, when the insecticides were mixed with a feeding attractant, a positive effect was observed only for adults of D. suzukii . Insecticides containing neonicotinoids (acetamiprid and thiamethoxam) and pyrolle (chlorfenapyr) caused intermediate mortality to adults of D. suzukii (40?60%) and low mortality for Z. indianus (mortality < 23%); however, these compounds reduced the larval infestation of the two species by 55?86%. Botanical (azadirachtin) and sulphur insecticides exhibited low toxicity (mortality < 40%) on adults and larvae of both species. CONCLUSION: Dimethoate, malathion, spinosad, spinetoram, lambda-cyhalothrin and cyantraniliprole are highly toxic to both larvaeandadultsof D. suzukii and Z.indianus .Theuseoftoxicbaitsforadultsof D. suzukii couldbeanalternativeinmanagement of this species. © 2016 Society of Chemical Industry Keywords: spotted-wing drosophila; fig fly; chemical control; strawberry; toxic bait; pest control.

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BACKGROUND: Drosophila suzukii is a primary insect pest that causes direct damage to fruits with a thin epidermis such as strawberries, cherries and blueberries. In strawberry fields, the co-occurrence of D. suzukii and Zaprionus indianus has increased production losses. This study evaluated the toxicities and effects of insecticidal baits to control adults and larvae of both D. suzukii and Z. indianus . RESULTS: Organophosphate (dimethoate and malathion), spinosyn (spinosad and spinetoram), pyrethroid (lambda-cyhalothrin) and diamide (cyantraniliprole) insecticides exhibited high toxicity to both adults and larvae of D. suzukii and Z. indianus (mortality > 80%) in topical and dip bioassays. However, when the insecticides were mixed with a feeding attractant, a positive effect was observed only for adults of D. suzukii . Insecticides containing neonicotinoids (acetamiprid and thiamethoxam) and pyrolle (chlorfenapyr) caused intermediate mortality to adults of D. suzukii (40?60%) and low mortality for Z. indianus (mortality < 23%); however, these compounds reduced the larval infestation of the two species by 55?86%. Botanical (azadirachtin) and sulphur insecticides exhibited low toxicity (mortality < 40%) on adults and larvae of both species. CONCLUSION: Dimethoate, malathion, spinosad, spinetoram, lambda-cyhalothrin and cyantraniliprole are highly toxic to both larvaeandadultsof D. suzukii and Z.indianus .Theuseoftoxicbaitsforadultsof D. suzukii couldbeanalternativeinmanagement of this species. © 2016 Society of Chemical Industry Keywords: spotted-wing drosophila; fig fly; chemical control; strawberry; toxic bait; pest control.