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1.
Braz. j. biol ; 84: e253948, 2024. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1355909

RESUMO

Abstract The assessment of the comparative effect of biosal (phytopesticide), deltamethrin, and lambda-cyhalothrin (pyrethroids) were made against two fodder pests, Hermolaus modestus and Hermolaus ocimumi by filter paper impregnation method. The activity of total protein contents, GPT (glutamic-pyruvic transaminase) and GOT (glutamic oxaloacetate transaminase) were affected in Hermolaus modestus and Hermolaus ocimumi against biosal, deltamethrin, and lambda cyhalothrin. The activity of total protein contents in H. modestus was 31.053%, 4.607%, and 24.575%, against biosal, deltamethrin, and lambda-cyhalothrin, respectively. The activity of total protein contents was observed as 24.202%, 15.25%, and 56.036% against deltamethrin, lambda-cyhalothrin, and biosal, respectively in H. ocimumi. The activity of GOT was observed as 98.675% for biosal 33.95% for deltamethrin and 83.619% for lambda-cyhalothrin in H. modestus. The GOT activity was estimated in H. ocimumi as 78.831%, 47.645%, and 71.287% against biosal, deltamethrin, and lambda-cyhalothrin, respectively. The efficacy of GPT enzyme against biosal, deltamethrin, and lambda-cyhalothrin was calculated as 89.26%, 73.07%, and 47.58%, respectively in H. modestus. The H. ocimumi showed GPT activity as 77.58% for biosal, 68.84% for deltamethrin, and 52.67% for lambda-cyhalothrin, respectively.


Resumo A avaliação do efeito comparativo do biosal (fitopesticida), deltametrina e lambda-cialotrina (piretróides) foi feita contra duas pragas forrageiras, Hermolaus modestus e Hermolaus ocimumi, pelo método de impregnação com papel de filtro. A atividade do conteúdo de proteína total, GPT (transaminase glutâmico-pirúvica) e GOT (oxaloacetato transaminase glutâmico) foram afetados em Hermolaus modestus e Hermolaus ocimumi contra biosal, deltametrina e lambda cialotrina. A atividade do conteúdo de proteína total em H. modestus foi 31.053%, 4.607% e 24.575%, contra biosal, deltametrina e lambda-cialotrina, respectivamente. A atividade do conteúdo de proteína total foi observada como 24.202%, 15.25% e 56,036% contra deltametrina, lambda-cialotrina e biosal, respectivamente em H. ocimumi. A atividade do GOT foi observada em 98.675% para o biosal, 33,95% para a deltametrina e 83.619% para a lambda-cialotrina em H. modestus. A atividade do GOT foi estimada em H. ocimumi como 78.831%, 47.645% e 71.287% contra biosal, deltametrina e lambda-cialotrina, respectivamente. A eficácia da enzima GPT contra biosal, deltametrina e lambda-cialotrina foi calculada como 89.26%, 73.07% e 47.58%, respectivamente em H. modestus. A H. ocimumi apresentou atividade GPT de 77.58% para biosal, 68.84% para deltametrina e 52.67% para lambda-cialotrina, respectivamente.


Assuntos
Animais , Piretrinas , Inseticidas , Heterópteros , Alanina Transaminase , Ração Animal , Nitrilas
2.
Braz. j. biol ; 84: e254479, 2024. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1355910

RESUMO

Abstract Earias vittellaFabricius, 1794 (Noctuidae: Lepidoptera) is deliberated to be one of the most destructive pests of cotton and okra vegetation in the world including Asia. The pest has established resistance to various synthetic insecticides. The use of bio-pesticide is one of the unconventional approaches to develop a vigorous ecosystem without harming non- target pests and beneficial natural insect fauna. In the present study, the toxicity levels of Citrullus colocynthis seed extract have been evaluated against the populations of E. vittellaunder standardized laboratory conditions. The toxic effects of C. colocynthis on development periods, protein contents and esterase activity of the life stages of E. vittella were also evaluated. The toxicity levels of methanol, ethanol, hexane, water and profenofos were evaluated on the 1st instar larvae of E. vittella. LC30 and LC80 concentrations exhibited the effectiveness of methanol-based C. colocynthis seed extract against 1st instar larvae of E. vitella. The enhanced larval and pupal periods were revealed in treated samples during the comparison with untreated samples. The intrinsic rate of increase, net reproductive rate in the LC30 and LC80 concentrations exposed larvae remained less than the control treatment. Fecundity, the esterase activity and protein contents were declined in LC30 and LC80 treated samples as compared to the control. The present findings suggest that C. colosynthis extracts based botanical insecticides are beneficial, ecosystem sustainable and can be integrated with insect management programs from environment safety perspective.


Resumo Earias vittella Fabricius, 1794 (Noctuidae: Lepidoptera) é considerada uma das pragas mais destrutivas de algodão e quiabo no mundo, incluindo a Ásia. Essa praga estabeleceu resistência a vários inseticidas sintéticos. O uso de biopesticidas é uma das abordagens não convencionais para desenvolver um ecossistema saudável sem prejudicar as pragas não alvo e a fauna natural benéfica de insetos. No presente estudo, os níveis de toxicidade do extrato de semente de Citrullus colocynthis foram avaliados nas populações de E. vittella em condições de laboratório padronizadas. Os efeitos tóxicos de C. colocynthis nos períodos de desenvolvimento, conteúdo de proteína e atividade esterase das fases de vida de E. vittella também foram avaliados. Os níveis de toxicidade de metanol, etanol, hexano, água e profenofós foram avaliados em larvas de 1º instar de E. vittella. As concentrações de LC30 e LC80 apresentaram eficácia do extrato de sementes de C. colocynthis à base de metanol contra larvas de 1º instar de E. vittella. Os períodos larval e pupal aumentados foram revelados nas amostras tratadas durante a comparação com as amostras não tratadas. A taxa intrínseca de aumento e a taxa reprodutiva líquida nas concentrações de larvas expostas LC30 e LC80 permaneceram menores do que o tratamento controle. A fecundidade, a atividade da esterase e o conteúdo de proteína diminuíram nas amostras tratadas com LC30 e LC80 em comparação com o controle. As presentes descobertas sugerem que os extratos de C. colocynthis à base de inseticidas botânicos são benéficos, sustentáveis ​​para o ecossistema e podem ser integrados com programas de manejo de insetos do ponto de vista da segurança ambiental.


Assuntos
Animais , Citrullus colocynthis , Inseticidas , Mariposas , Extratos Vegetais/farmacologia , Ecossistema , Larva
3.
Braz. j. biol ; 83: e247676, 2023. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1345527

RESUMO

Abstract Development of insecticides resistance mainly hinge with managements techniques for the control of Jassid, Amrasca biguttutla biguttutla. Five insecticides were applied against field collected and laboratory rared jassid populations during the years of 2017 to 2019 to profile their resistance level against field population of jassid through leaf dip method. Very low resistance level was found in jassid against confidor whereas high level of resistance was observed by pyriproxyfen against other test insecticides. Gradual resistance was observed against diafenthiuron. It is concluded that for the management of Jassid repetition of same insecticide should be avoided. The use of confidor may be reduced to overcome resistance against Jassid.


Resumo Desenvolvimento da resistência a inseticidas principalmente em dobradiça com técnicas de manejo para o controle de jassid, Amrasca biguttutla biguttutla. Cinco inseticidas foram aplicados contra populações de jassídeos coletados em campo e em laboratório durante os anos de 2017 a 2019 para traçar o perfil de seu nível de resistência contra populações de jassídeos em campo através do método de imersão nas folhas. Nível de resistência muito baixo foi encontrado em jassid contra confidor, enquanto alto nível de resistência foi observado por piriproxifeno contra outros inseticidas de teste. Resistência gradual foi observada contra o diafenthiuron. Conclui-se que, para o manejo do jassid, a repetição do mesmo inseticida deve ser evitada. O uso de confidor pode ser reduzido para superar a resistência contra jassid.


Assuntos
Animais , Hemípteros , Inseticidas/farmacologia , Resistência a Inseticidas , Laboratórios
4.
Braz. j. biol ; 83: e250373, 2023. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1339376

RESUMO

Abstract Honey is a suitable matrix for the evaluation of environmental contaminants including organochlorine insecticides. The present study was conducted to evaluate residues of fifteen organochlorine insecticides in honey samples of unifloral and multifloral origins from Dir, Pakistan. Honey samples (5 g each) were extracted with GC grade organic solvents and then subjected to Rotary Evaporator till dryness. The extracts were then mixed with n-Hexane (5 ml) and purified through Column Chromatography. Purified extracts (1μl each) were processed through Gas Chromatograph coupled with Electron Capture Detector (GC-ECD) for identification and quantification of the insecticides. Of the 15 insecticides tested, 46.7% were detected while 53.3% were not detected in the honey samples. Heptachlor was the most prevalent insecticide with a mean level of 0.0018 mg/kg detected in 80% of the samples followed by β-HCH with a mean level of 0.0016 mg/kg detected in 71.4% of the honey samples. Honey samples from Acacia modesta Wall. were 100% positive for Heptachlor with a mean level of 0.0048 mg/kg followed by β-HCH with a mean level of 0.003 mg/kg and frequency of 83.3%. Minimum levels of the tested insecticides were detected in the unifloral honey from Ziziphus jujuba Mill. Methoxychlor, Endosulfan, Endrin and metabolites of DDT were not detected in the studied honey samples. Some of the tested insecticides are banned in Pakistan but are still detected in honey samples indicating their use in the study area. The detected levels of all insecticides were below the Maximum Residue Levels (MRLs) and safe for consumers. However, the levels detected can cause mortality in insect fauna. The use of banned insecticides is one of the main factors responsible for the declining populations of important insect pollinators including honeybees.


Resumo O mel é uma matriz adequada para a avaliação de contaminantes ambientais, incluindo inseticidas organoclorados. O presente estudo foi conduzido para avaliar resíduos de 15 inseticidas organoclorados em amostras de mel de origem unifloral e multifloral de Dir, Paquistão. Amostras de mel (5 g cada) foram extraídas com solventes orgânicos de grau GC e, em seguida, submetidas ao evaporador rotativo até a secura. Os extratos foram então misturados com n-hexano (5 ml) e purificados por cromatografia em coluna. Os extratos purificados (1μl cada) foram processados através de cromatógrafo gasoso acoplado a detector de captura de elétrons (GC-ECD) para identificação e quantificação dos inseticidas. Dos 15 inseticidas testados, 46,7% foram detectados enquanto 53,3% não foram detectados nas amostras de mel. O heptacloro foi o inseticida mais prevalente com um nível médio de 0,0018 mg / kg detectado em 80% das amostras, seguido por β-HCH com um nível médio de 0,0016 mg / kg detectado em 71,4% das amostras de mel. Amostras de mel da parede de Acacia modesta foram 100% positivos para heptacloro com um nível médio de 0,0048 mg / kg seguido por β-HCH com um nível médio de 0,003 mg / kg e frequência de 83,3%. Níveis mínimos dos inseticidas testados foram detectados no mel unifloral de Ziziphus jujuba da usina. Metoxicloro, Endosulfan, Endrin e metabólitos do DDT não foram detectados nas amostras de mel estudadas. Alguns dos inseticidas testados são proibidos no Paquistão, mas ainda são detectados em amostras de mel, indicando seu uso na área de estudo. Os níveis detectados de todos os inseticidas estavam abaixo dos Níveis Máximos de Resíduos (MRLs) e seguros para os consumidores. No entanto, os níveis detectados podem causar mortalidade na fauna de insetos. O uso de inseticidas proibidos é um dos principais fatores responsáveis pelo declínio das populações de importantes insetos polinizadores, incluindo as abelhas.


Assuntos
Animais , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/toxicidade , Mel/análise , Inseticidas/toxicidade , Abelhas , Biomarcadores Ambientais , Endossulfano/análise
5.
Braz. j. biol ; 83: e240842, 2023. tab
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1339375

RESUMO

Abstract This research aimed to investigate various mosquitocidal activities of Chenopodium botrys whole- plant n-hexane extract against Culex quinquefasciatus. The extract showed remarkable larvicidal, pupicidal, adulticidal, oviposition deterrent and adult emergence inhibitory activities against Cx. quinquefasciatus. During the larvicidal and pupicidal activities, the 24-hour lethal concentration (LC50) of extract against 2nd instar larvae, 4th instar larvae and pupae were 324.6, 495.6 and 950.8 ppm, respectively. During the CDC (Centers for Disease Control and Prevention) bottle bioassay for adulticidal activity, the median knockdown times (KDT50) at 1.25% concentration was 123.4 minutes. During the filter paper impregnation bioassay for adulticidal activity, the KDT50 value at 0.138 mg/cm2 concentration was 48.6 minutes. The extract was fractionated into 14 fractions through silica gel column chromatography which were then combined into six fractions on the basis of similar retention factor (Rf) value. These fractions were screened for adulticidal activity by applying CDC bottle bioassay. The fraction obtained through 60:40 to 50:50% n-hexanes-chloroform mobile phase with 0.5 Rf value showed 100% adulticidal activity at 0.2% concentration. During oviposition deterrent activity, the highest concentration (1000 ppm) showed 71.3 ± 4.4% effective repellence and 0.6 ± 0.1 oviposition activity index. During adult emergence inhibition activity, the median emergence inhibition (EI50) value was 312.3 ppm. From the outcome of the present investigation, it is concluded that the n-hexane extract of C. botrys whole- plant possesses strong larvicidal, pupicidal, adulticidal, oviposition deterrent and adult emergence inhibitory activities against Cx. quinquefasciatus.


Resumo Esta pesquisa teve como objetivo investigar várias atividades mosquitocidas do extrato n-hexano de planta inteira de Chenopodium botrys contra Culex quinquefasciatus. O extrato mostrou atividades larvicida, pupicida, adulticida, dissuasora de oviposição e inibidora da emergência de adultos contra a Cx. quinquefasciatus. Durante as atividades larvicida e pupicida, a concentração letal de 24 horas (CL50) do extrato contra larvas de 2º estádio, larvas de 4º estádio e pupa foi de 324,6, 495,6 e 950,8 ppm, respectivamente. Durante o bioensaio com frasco do CDC (Centros para Controle e Prevenção de Doenças) para adulticida, o tempo médio de desativação (KDT50) na concentração de 1,25% foi de 123,4 minutos. Durante o bioensaio de impregnação com papel de filtro para a atividade adulticida do extrato, o valor KDT50 na concentração de 0,138 mg / cm2 foi de 48,6 minutos. O extrato foi fracionado em 14 frações através de cromatografia em coluna de gel de sílica que foram então combinadas em seis frações com base em um valor de fator de retenção (Rf) semelhante. Essas frações foram selecionadas quanto à atividade adulticida por meio da aplicação do bioensaio com garrafa do CDC. A fração obtida através da fase móvel de n-hexanos-clorofórmio 60:40% a 50:50% com valor de 0,5 Rf apresentou atividade adulticida de 100% na concentração de 0,2%. Durante a atividade de dissuasão da oviposição, a maior concentração de extrato (1000 ppm) apresentou repelência efetiva de 71,3 ± 4,4% e índice de atividade de oviposição de 0,6 ± 0,1. Durante a atividade de inibição da emergência de adultos, o valor médio de inibição da emergência (EI50) foi de 312,3 ppm. A partir do resultado da presente investigação, conclui-se que o extrato de n-hexano da planta inteira de C. botrys possui fortes atividades larvicida, pupicida, adulticida, dissuasora da oviposição e inibidora da emergência de adultos contra a Cx. quinquefasciatus.


Assuntos
Animais , Culex , Chenopodium , Inseticidas/farmacologia , Extratos Vegetais/farmacologia , Folhas de Planta , Hexanos , Larva
6.
Braz. j. biol ; 83: e248122, 2023. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1355851

RESUMO

Abstract Being vector of West Nile Virus and falariasis the control of Culex quinquefasciatus is likely to be essential. Synthetic insecticide treatment is looking most effective for vectors mosquito control. However, these products are toxic to the environment and non-target organisms. Consequently, ecofriendly control of vectors mosquito is needed. In this regard botanical insecticide is looking more fruitful. Therefore, the present research aimed to investigate the effectiveness of methanolic extract and various fractions, including, n-hexane, ethyl-acetate, chloroform, and aqueous fraction, obtained from methanolic extract of Ailanthus altissima, Artemisia scoparia, and Justicia adhatoda using separating funnel against larval, pupal, and adult stages of Culex quinquefasciatus. The larvae and pupae of Culex quinquefasciatus were exposed to various concentrations (31.25-1000 ppm) of methanolic extract and its fractions for 24 hours of exposure period. For knock-down bioassay (filter paper impregnation bioassay) different concentration of the methanolic extract and its various fractions (i.e. 0.0625, 0.125, 0.25, 0.5 and 1mg/mL) were applied for 1 hour exposure period. The results were statistically analysed using standard deviation, probit analysis, and linear regression. The R2 values of larvae, pupae, and adult range from 0.4 to 0.99. The values of LC50 (concentration causing 50% mortality) for late 3rd instar larvae after 24 hours exposure period range from 93-1856.7 ppm, while LC90 values range from 424 -7635.5ppm. The values of LC50for pupae range form 1326.7-6818.4ppm and and values of LC90 range from 3667.3-17427.9ppm, respectively. The KDT50 range from 0.30 to 2.8% and KDT90 values range from1.2 to 110.8%, respectively. In conclusion, Justicia adhatoda may be effective for controlling populations of vector mosquito.


Resumo Por ser o vetor do vírus do Nilo Ocidental e da falaríase, o controle de Culex quinquefasciatus Say é provavelmente essencial. O tratamento com inseticida sintético parece ser mais eficaz para o controle dos mosquitos vetores. No entanto, esses produtos são tóxicos para o meio ambiente e organismos não visados. Consequentemente, o controle ecológico dos mosquitos vetores é necessário. Nesse sentido, o inseticida botânico parece mais produtivo. Portanto, a presente pesquisa teve como objetivo investigar a eficácia do extrato metanólico e de várias frações, incluindo n-hexano, acetato de etila, clorofórmio e fração aquosa, obtidos do extrato metanólico de Ailanthus altissima (Mill.) Swingle, Artemisia scoparia Waldst. & Kit. e Justicia adhatoda L. usando funil de separação contra os estágios larval, pupal e adulto de C. quinquefasciatus. As larvas e pupas de C. quinquefasciatus foram expostas a várias concentrações (31,25-1000 ppm) de extrato metanólico, e suas frações por 24 horas de período de exposição. Para o bioensaio knock-down (bioensaio de impregnação de papel de filtro), diferentes concentrações do extrato metanólico e suas várias frações (ou seja, 0,0625, 0,125, 0,25, 0,5 e 1 mg / mL) foram aplicadas por um período de exposição de 1 hora. Os resultados foram analisados ​​estatisticamente usando desvio padrão, análise Probit e regressão linear. Os valores de R2 de larvas, pupas e adultos variaram de 0,4 a 0,99. Os valores de LC50 (concentração que causa 50% de mortalidade) para larvas de terceiro estádio tardio após 24 horas de período de exposição variaram de 93-1856,7 ppm, enquanto os valores de LC90 variaram de 424-7635,5ppm. Os valores de LC50 para pupas variaram de 1326,7-6818,4 ppm e os valores de LC90 variaram de 3667,3-17427,9 ppm, respectivamente. O KDT50 variou de 0,30 a 2,8% e os valores de KDT90 variaram de 1,2 a 110,8%, respectivamente. Por fim, a espécie J. adhatoda pôde ser eficaz para controlar populações de mosquitos vetores.


Assuntos
Animais , Culex , Inseticidas/farmacologia , Anopheles , Extratos Vegetais/farmacologia , Folhas de Planta , Mosquitos Vetores , Larva
7.
Braz. j. biol ; 83: e246230, 2023. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1339369

RESUMO

Abstract Dengue fever vectored by the mosquito Aedes aegypti is one of the most rapidly spreading insect-borne diseases. Current reliance of dengue vector control is mostly on chemical insecticides. Growing insecticide resistance in the primary mosquito vector, Aedes aegypti, limits the effectiveness of vector control through chemical insecticides. These chemical insecticides also have negative environmental impacts on animals, plants and human health. Myco-biocontrol agents are naturally occurring organisms and are found to be less damaging to the environment as compared to chemical insecticides. In the present study, entomopathogenic potential of local strains of fungi isolated from soil was assessed for the control of dengue vector. Local fungal isolates presents better alternative to introducing a foreign biocontrol strain, as they may be better adapted to environmental conditions of the area to survive and may have more entomopathogenic efficacy against target organism. Larvicidal efficacy of Fusarium equiseti and Fusarium proliferatum was evaluated against Aedes aegypti. Local strains of F. equiseti (MK371718) and F. proliferatum (MK371715) were isolated from the soil of Changa Manga Forest, Pakistan by using insect bait method. Larvicidal activity of two Fusarium spp. was tested against forth instar larvae of A. aegypti in the laboratory, using concentrations 105, 106, 107 and 108 conidia /ml. LC50 values for F. equiseti after 24h, 48h, 72h and 96h of exposure were recorded as 3.8x 108, 2.9x107, 2.0x107, and 7.1x106 conidia /ml respectively while LC50 values for F. proliferatum were recorded as 1.21x108, 9.6x107, 4.2x107, 2.6x107 conidia /ml respectively after 24h, 48h, 72h and 96h of exposure. The results indicate that among two fungal strains F. equiseti was found to be more effective in terms of its larvicidal activity than F. proliferatum against larvae of A. aegypti.


Resumo A dengue transmitida pelo mosquito Aedes aegypti é uma das doenças transmitidas por insetos de propagação mais rápida. A dependência atual do controle do vetor da dengue é principalmente de inseticidas químicos. O aumento da resistência a inseticidas no principal vetor do mosquito, Aedes aegypti, limita a eficácia do controle do vetor por meio de inseticidas químicos. Esses inseticidas químicos também têm impactos ambientais negativos sobre os animais, plantas e saúde humana. Os agentes de micobiocontrole são organismos que ocorrem naturalmente e são menos prejudiciais ao meio ambiente em comparação com os inseticidas químicos. No presente estudo, avaliou-se o potencial entomopatogênico de cepas locais de fungos isolados do solo para o controle do vetor da dengue. Isolados de fungos locais apresentam melhor alternativa para a introdução de uma cepa de biocontrole estrangeira, pois podem ser mais bem adaptados às condições ambientais da área para sobreviver e podem ter maior eficácia entomopatogênica contra o organismo-alvo. A eficácia larvicida de Fusarium equiseti e Fusarium proliferatum foi avaliada contra Aedes aegypti. Cepas locais de F. equiseti (MK371718) e F. proliferatum (MK371715) foram isoladas do solo de Changa Manga Forest, Paquistão, usando o método de isca para insetos. Atividade larvicida de dois Fusarium spp. foi testado contra larvas de quarto ínstar de A. aegypti em laboratório, nas concentrações 105, 106, 107 e 108 conídios / ml. Os valores de LC50 para F. equiseti após 24 h, 48 h, 72 h e 96 h de exposição foram registrados como 3,8x 108, 2,9x107, 2,0x107 e 7,1x106 conídios / ml, respectivamente, enquanto os valores de LC50 para F. proliferatum foram registrados como 1,21x108, 9,6 x107, 4,2x107, 2,6x107 conídios / ml, respectivamente, após 24 h, 48 h, 72 h e 96 h de exposição. Os resultados indicam que entre duas cepas de fungos F. equiseti se mostrou mais eficaz em termos de atividade larvicida do que F. proliferatum contra larvas de A. aegypti.


Assuntos
Humanos , Animais , Aedes , Fusarium , Inseticidas/farmacologia , Paquistão , Solo , Extratos Vegetais , Florestas , Mosquitos Vetores , Larva
8.
Braz. j. biol ; 83: e248154, 2023. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1339365

RESUMO

Abstract The cotton boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is a key cotton crop pest in Brazil. Adverse climatic factors, such as high temperatures and low soil moisture, dehydrate oviposited cotton squares (bud flowers) on the ground and cause high mortality of its offspring within these plant structures. The objective of this research was to evaluate the mortality of the cotton boll weevil in drip and sprinkler irrigated cotton crops. The experimental design was in randomized blocks with two treatments: drip (T1) and sprinkler (T2, control) irrigated cotton crops with sixteen replications. Each parcel had one emergence cage, installed between two cotton rows per irrigation system, with 37 cotton squares with opened oviposition punctures and yellowish bracts, to capture adult cotton boll weevils. The average number of boll weevils that emerged from the cotton squares and the causes of mortality at different development stages were determined per treatment. Third-generation life tables of the boll weevil were prepared using the natural mortality data in drip and sprinkler irrigation treatments and plus actual, apparent and indispensable mortality rates and the lethality of each mortality cause. We conclude that the application of water directly to the root zone of the plants in a targeted manner, using the drip irrigation system, can cause high mortality of the cotton boll weevil immature stages inside cotton squares fallen on the ground. This is because the cotton squares fallen on the drier and hotter soil between the rows of drip-irrigated cotton dehydrates causing the boll weevils to die. This is important because it can reduce its population density of the pest and, consequently, the number of applications of chemical insecticides for its control. Thus, contributing to increase the viability of cotton production, mainly in areas of the Brazilian semiarid region where the cotton is cultivated in organic system.


Resumo O bicudo-do-algodoeiro, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), é uma praga-chave da cultura do algodão no Brasil. Fatores climáticos adversos, como altas temperaturas e baixa umidade do solo, desidratam os botões florais de algodão ovipositados caídos ao solo e causam alta mortalidade de seus descendentes dentro dessas estruturas vegetais.O objetivo desta pesquisa foi avaliar a mortalidade do bicudo-do-algodoeiro em lavouras de algodão irrigadas por gotejamento e aspersão. O delineamento experimental foi em blocos casualizados com dois tratamentos: cultivo de algodão irrigado por gotejamento (T1) e aspersão (T2, testemunha) com dezesseis repetições. Cada parcela possuía uma gaiola de emergência, instalada entre duas fileiras de algodão por sistema de irrigação, com 37 botões florais de algodão com orifícios de oviposição, brácteas abertas e amarelecidas, para captura do bicudo adulto. O número médio de bicudos que emergiu dos botões florais de algodão e as causas de mortalidade, em diferentes estágios de desenvolvimento, foram determinados por tratamento. As tabelas de vida de terceira geração do bicudo-do-algodoeiro foram preparadas usando os dados de mortalidade natural em tratamentos de irrigação por gotejamento e aspersão e as taxas de mortalidade reais, aparentes e indispensáveis e a letalidade de cada causa de mortalidade. Concluímos que a aplicação de água diretamente na zona radicular das plantas de forma direcionada, utilizando o sistema de irrigação por gotejamento, pode causar altas mortalidade dos estágios imaturos do bicudo-do-algodoeiro nos botões florais de algodão caídos no solo. Isso ocorre porque os botões florais de algodão caídos no solo mais seco e mais quente entre as fileiras do algodão irrigado por gotejamento desidratam, causando a morte dos bicudos. Isso é importante por poder reduzir a densidade populacional desse inseto e, consequentemente, o número de aplicações de inseticidas químicos para seu controle. Assim, contribuindo para aumentar a viabilidade da produção de algodão, principalmente em áreas do semiárido brasileiro em sistema orgânico.


Assuntos
Animais , Besouros , Gorgulhos , Inseticidas , Oviposição , Produtos Agrícolas
9.
Braz. j. biol ; 83: e240118, 2023. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1278559

RESUMO

Abstract For many centuries human populations have been suffering and trying to fight with disease-bearing mosquitoes. Emerging and reemerging diseases such as Dengue, Zika, and Chikungunya affect billions of people around the world and recently has been appealing to control with chemical pesticides. Malathion (MT) is one of the main pesticides used against mosquitoes, the vectors of these diseases. This study aimed to assess cytotoxicity and mutagenicity of the malathion for the bioindicator Allium cepa L. using a multivariate and integrative approach. Moreover, an appendix table was compiled with all available literature of insecticides assessed by the Allium cepa system to support our discussion. Exposures during 48h to 0.5 mg mL-1 and 1.0 mg mL-1 MT were compared to the negative control (distilled water) and positive control (MMS solution at 10 mg L-1). The presence of chromosomal aberrations, micronuclei frequency, and mitotic index abnormalities was evaluated. Anaphase bridges were the alterations with higher incidence and presented a significantly elevated rate in the concentration of 0.5 mg mL-1, including when compared to the positive control. The integrative discriminant analysis summarizes that MT in assessed concentrations presented effects like the positive control, corroborating its potential of toxicity to DNA. Therefore, it is concluded that MT in its pure composition and in realistic concentrations used, has genotoxic potential in the biological assessment of A. cepa cells. The multivariate integrative analysis was fundamental to show a whole response of all data, providing a global view of the effect of MT on DNA.


Resumo Por muitos séculos, as populações humanas sofrem e tentam combater os mosquitos transmissores de doenças. Doenças emergentes e reemergentes como Dengue, Zika e Chikungunya afetam bilhões de pessoas em todo o mundo e, recentemente, vem apelando ao controle com pesticidas químicos. O Malation (MT) é um dos principais pesticidas usados ​​contra mosquitos, vetores dessas doenças. O objetivo deste estudo foi avaliar a citotoxicidade e a mutagenicidade do MT para o bioindicador Allium cepa L. usando uma abordagem multivariada e integrativa. Além disso, uma tabela suplementar foi compilada com toda a literatura disponível de inseticidas avaliada pelo sistema Allium cepa para apoiar nossa discussão. Exposições ao MT durante 48h a 0,5 mg mL-1 e 1,0 mg mL-1 foram comparadas a um controle negativo (água destilada) e um controle positivo (10 mg L-1 de MMS). Foram avaliadas a presença de aberrações cromossômicas, frequência de micronúcleos e anormalidades no índice mitótico. As pontes anafásicas foram as alterações com maior incidência e apresentaram uma taxa significativamente elevada na concentração de 0,5 mg mL-1, inclusive quando comparadas ao controle positivo. A análise discriminante integrativa resume que o MT nas concentrações avaliadas apresentou efeitos semelhantes ao controle positivo, corroborando seu potencial de toxicidade para o DNA. Portanto, conclui-se que o MT, em sua composição pura e nas concentrações realistas utilizadas, possui potencial genotóxico na avaliação biológica de células de A. cepa. A análise integrativa multivariada foi fundamental para mostrar uma resposta completa de todos os dados, fornecendo uma visão global do efeito da MT no DNA.


Assuntos
Humanos , Animais , Zika virus , Infecção por Zika virus , Inseticidas/toxicidade , Dano ao DNA , Aberrações Cromossômicas , Raízes de Plantas , Cebolas , Mosquitos Vetores , Malation/toxicidade , Índice Mitótico
10.
Braz. j. biol ; 83: e247539, 2023. tab
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1278542

RESUMO

Abstract Numerous studies have investigated the chemical composition and biological activities of essential oils from different Citrus species fruit peel, leaves and flowers. This paper aims to investigate the chemical composition, larvicidal and antileishmanial activities of essential oil from Citrus reticulata fruit peel (CR-EO). CR-EO was obtained by hydrodistillation in a Clevenger-type apparatus and its chemical composition was analyzed by GC-MS and GC-FID. Limonene (85.7%), ɣ-terpinene (6.7%) and myrcene (2.1%) were identified as its major components. CR-EO showed high activity against promastigote forms of Leishmania amazonensis (IC50 = 8.23 µg/mL). CR-EO also exhibited high larvicidal activity against third instar Aedes aegypti larvae at a lethal concentration (LC50 = 58.35 µg/mL) and 100% mortality at 150 µg/mL. This study suggests, for the first time, the potential use of CR-EO against this important mosquito-borne viral disease caused by the genus Aedes.


Resumo Numerosos estudos têm investigado a composição química e as atividades biológicas de óleos essenciais extraídos de cascas dos frutos, folhas e flores de diferentes espécies de Citrus. Este trabalho tem como objetivo investigar a composição química e as atividades larvicida e leishmanicida in vitro do óleo essencial das cascas dos frutos de Citrus reticulata (CR-EO). CR-EO foi obtido pela técnica de extração em aparelho Clevenger e sua composição química foi determinada por CG-EM e CG-DIC. Limoneno (85,7%), ɣ-terpineno (6,7%) and mirceno (2,1%) foram identificados como os constituintes majoritários. CR-EO mostrou alta atividade contra as formas promastigota de Leishmania amazonensis (CI50 = 8,23 µg/mL). CR-EO também exibiu alta atividade larvicida contra as larvas do terceiro estágio do Aedes aegypti com concentração letal (CL50 = 58,35 µg/mL) e mortalidade de 100% em 150 µg/mL. Este estudo sugere, pela primeira vez, o uso potencial de CR-EO contra esta importante doença viral transmitida por mosquitos do gênero Aedes.


Assuntos
Animais , Óleos Voláteis/farmacologia , Citrus , Aedes , Inseticidas/farmacologia , Frutas , Larva
11.
Braz. j. biol ; 83: e244647, 2023. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1278527

RESUMO

Abstract The essential oil of citronella (Cymbopogon winterianus) has several biological activities, among them the insect repellent action. Some studies showed that cinnamic acid esters can be applied as natural pesticides, insecticides and fungicides. In this context, the objective of the present work was to evaluate the production of esters from citronella essential oil with cinnamic acid via enzymatic esterification. Besides, the essential oil toxicity before and after esterification against Artemia salina and larvicidal action on Aedes aegypti was investigated. Esters were produced using cinnamic acid as the acylating agent and citronella essential oil (3:1) in heptane and 15 wt% NS 88011 enzyme as biocatalysts, at 70 °C and 150 rpm. Conversion rates of citronellyl and geranyl cinnamates were 58.7 and 69.0% for NS 88011, respectively. For the toxicity to Artemia salina LC50 results of 5.29 μg mL-1 were obtained for the essential oil and 4.36 μg mL-1 for the esterified oils obtained with NS 88011. In the insecticidal activity against Aedes aegypti larvae, was obtained LC50 of 111.84 μg mL-1 for the essential oil of citronella and 86.30 μg mL-1 for the esterified oils obtained with the enzyme NS 88011, indicating high toxicity of the esters. The results demonstrated that the evaluated samples present potential of application as bioinsecticide.


Resumo O óleo essencial de citronela (Cymbopogon winterianus) possui diversas atividades biológicas, entre elas a ação repelente a insetos. Alguns estudos mostraram que os ésteres do ácido cinâmico podem ser aplicados como pesticidas naturais, inseticidas e fungicidas. Nesse contexto, o objetivo do presente trabalho foi avaliar a produção de ésteres a partir do óleo essencial de citronela com ácido cinâmico via esterificação enzimática. Além disso, foi investigada a toxicidade do óleo essencial antes e após a esterificação contra Artemia salina e a ação larvicida sobre Aedes aegypti. Os ésteres foram produzidos utilizando ácido cinâmico como agente acilante e óleo essencial de citronela (3: 1) em heptano e 15% em peso da enzima NS 88011 como biocatalisadores, a 70 ° C e 150 rpm. As taxas de conversão de cinamatos de citronelil e geranil foram 58,7 e 69,0% para NS 88011, respectivamente. Para a toxicidade sobre Artemia salina foram obtidos CL50 de 5,29 μg mL-1 para o óleo essencial e 4,36 μg mL-1 para os óleos esterificados com NS 88011. Na atividade inseticida contra larvas de Aedes aegypti, obteve-se CL50 de 111,84 μg mL-1 para o óleo essencial de citronela e 86,30 μg mL-1 para os óleos esterificados com a enzima NS 88011, indicando alta toxicidade dos ésteres. Os resultados demonstraram que as amostras avaliadas apresentam potencial de aplicação como bioinseticida.


Assuntos
Animais , Óleos Voláteis/toxicidade , Aedes , Cymbopogon , Repelentes de Insetos , Inseticidas/toxicidade , Esterificação , Larva
12.
J Insect Sci ; 22(3)2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35526103

RESUMO

The control of mosquito populations using insecticides is increasingly threatened by the spread of resistance mechanisms. Dieldrin resistance, conferred by point mutations in the Rdl gene encoding the γ-aminobutyric acid receptor, has been reported at high prevalence in mosquito populations in response to selective pressures. In this study, we monitored spatio-temporal dynamics of the resistance-conferring RdlR allele in Aedes (Stegomyia) albopictus (Skuse, 1895) and Culex (Culex) quinquefasciatus (Say, 1823) populations from Reunion Island. Specimens of both mosquito species were sampled over a 12-month period in three cities and in sites located at lower (<61 m) and higher (between 503 and 564 m) altitudes. Mosquitoes were genotyped using a molecular test detecting the alanine to serine substitution (A302S) in the Rdl gene. Overall, the RdlR frequencies were higher in Cx. quinquefasciatus than Ae. albopictus. For both mosquito species, the RdlR frequencies were significantly influenced by location and altitude with higher RdlR frequencies in the most urbanized areas and at lower altitudes. This study highlights environmental factors that influence the dynamics of insecticide resistance genes, which is critical for the management of insecticide resistance and the implementation of alternative and efficient vector control strategies.


Assuntos
Aedes , Culex , Inseticidas , Aedes/fisiologia , Animais , Culex/genética , Dieldrin , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mosquitos Vetores/genética , Reunião
13.
J Insect Sci ; 22(3)2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35512683

RESUMO

Helicoverpa armigera (Hübner) (Noctuidae: Lepidopetra) is a polyphagous pest of major crops grown in India. To prevent the damage caused by H. armigera farmers rely heavily on insecticides of diverse groups on a regular basis which is not a benign practice, environmentally and economically. To provide more efficient and accurate information on timely application of insecticides, this research was aimed to develop a forecast model to predict population dynamics of pod borer using Autoregressive Integrated Moving Average (ARIMA) and Artificial Neural Networks (ANN). The data used in this study were collected from the randomly installed sex pheromone traps at International Crops Research Institute for the Semi-arid Tropics (ICRISAT), Patancheru, Hyderabad. Several ARIMA (p, d, q) (P, D, Q) and ANN models were developed using the historical trap catch data. ARIMA model (1,0,1), (1,0,2) with minimal BIC, RMSE, MAPE, MAE, and MASE values and higher R2 value (0.53) was selected as the best ARIMA fit model, and neural network (7-30-1) was found to be the best fit to predict the catches of male moths of pod borer from September 2021 to August 2023. A comparative analysis performed between the ARIMA and ANN, shows that the ANN based on feed forward neural networks is best suited for effective pest prediction. With the developed ARIMA model, it would be easier to predict H. armigera adult population dynamics round the year and timely intervention of control measures can be followed by appropriate decision-making schedule for insecticide application.


Assuntos
Inseticidas , Mariposas , Animais , Previsões , Incidência , Masculino , Redes Neurais de Computação
14.
Parasit Vectors ; 15(1): 156, 2022 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-35505385

RESUMO

BACKGROUND: The city of Guangzhou has been the epicenter of dengue fever in China since the 1990s, with Aedes albopictus being the primary vector. The main method used to control vectors and prevent dengue fever has been the application of chemical insecticides; however, this control strategy has resulted in the development of resistance to these insecticides in mosquitoes. Here we report our investigation of the patterns of knockdown resistance (kdr) mutations in 15 field populations of Ae. albopictus collected from 11 districts in Guangzhou. RESULTS: Four mutant alleles (V1016G, F1534S, F1534C, F1534L) were detected in domain II and III of the voltage-gated sodium channel (VGSC) gene. Various allele frequencies of kdr mutations were observed (3.1-25.9% for V1016G, 22.6-85.5% for F1534S, 0-29.0% for F1534L, 0.6-54.2% for F1534C). Seven kdr haplotypes (VF, VS, VL, VC, GF, GC, GS) were identified; the highest frequency of haplotypes was found for the single mutant haplotype VS (50.8%), followed by the wild-type VF haplotype (21.7%) and the single mutant haplotype VC (11.9%). Of the three double mutant haplotypes, GF was the most frequent (8.8%), followed by GC (1.2%) and GS (0.8%). Aedes albopictus showed spatial heterogeneity in deltamethrin resistance in populations collected in Guangzhou. We also observed significant differences in haplotype frequency. The frequency of the VC haplotype was significantly higher in high-risk dengue areas than in low-risk ones. CONCLUSIONS: The kdr allele V1016G was discovered for the first time in Guangzhou. Genetic isolation in mosquito populations and long-term insecticide selection seem to be responsible for the persistent, patchy distribution of kdr mutant alleles. The small-scale spatial heterogeneity in the distribution and frequency of kdr mutations may have important implications for vector control operations and insecticide resistance management strategies.


Assuntos
Aedes , Dengue , Inseticidas , Aedes/genética , Animais , China , Dengue/prevenção & controle , Inseticidas/farmacologia , Mosquitos Vetores/genética , Mutação
15.
Environ Health ; 21(1): 46, 2022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-35501856

RESUMO

BACKGROUND: Dietary habits have a profound influence on the metabolic activity of gut microorganisms and their influence on health. Concerns have been raised as to whether the consumption of foodstuffs contaminated with pesticides can contribute to the development of chronic disease by affecting the gut microbiome. We performed the first pesticide biomonitoring survey of the British population, and subsequently used the results to perform the first pesticide association study on gut microbiome composition and function from the TwinsUK registry. METHODS: Dietary exposure of 186 common insecticide, herbicide, or fungicide residues and the faecal microbiome in 65 twin pairs in the UK was investigated. We evaluated if dietary habits, geographic location, or the rural/urban environment, are associated with the excretion of pesticide residues. The composition and metabolic activity of faecal microbiota was evaluated using shotgun metagenomics and metabolomics respectively. We performed a targeted urine metabolomics analysis in order to evaluate whether pesticide urinary excretion was also associated with physiological changes. RESULTS: Pyrethroid and/or organophosphorus insecticide residues were found in all urine samples, while the herbicide glyphosate was found in 53% of individuals. Food frequency questionnaires showed that residues from organophosphates were higher with increased consumption of fruit and vegetables. A total of 34 associations between pesticide residue concentrations and faecal metabolite concentrations were detected. Glyphosate excretion was positively associated with an overall increased bacterial species richness, as well as to fatty acid metabolites and phosphate levels. The insecticide metabolite Br2CA, reflecting deltamethrin exposure, was positively associated with the phytoestrogens enterodiol and enterolactone, and negatively associated with some N-methyl amino acids. Urine metabolomics performed on a subset of samples did not reveal associations with the excretion of pesticide residues. CONCLUSIONS: The consumption of conventionally grown fruit and vegetables leads to higher ingestion of pesticides with unknown long-term health consequences. Our results highlight the need for future dietary intervention studies to understand effects of pesticide exposure on the gut microbiome and possible health consequences.


Assuntos
Herbicidas , Inseticidas , Microbiota , Resíduos de Praguicidas , Praguicidas , Adulto , Exposição Dietética/análise , Herbicidas/análise , Humanos , Inseticidas/análise , Compostos Organofosforados , Resíduos de Praguicidas/análise , Verduras/química
16.
Parasit Vectors ; 15(1): 163, 2022 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-35527275

RESUMO

BACKGROUND: Malaria remains one of the most devastating diseases globally, and the control of mosquitoes as the vector is mainly dependent on chemical insecticides. Elevated temperatures associated with future warmer climates could affect mosquitoes' metabolic enzyme expression and increase insecticide resistance, making vector control difficult. Understanding how mosquito rearing temperatures influence their susceptibility to insecticide and expression of metabolic enzymes could aid in the development of novel tools and strategies to control mosquitoes in a future warmer climate. This study evaluated the effects of temperature on the susceptibility of Anopheles gambiae sensu lato (s.l.) mosquitoes to pyrethroids and their expression of metabolic enzymes. METHODS: Anopheles gambiae s.l. eggs obtained from laboratory-established colonies were reared under eight temperature regimes (25, 28, 30, 32, 34, 36, 38, and 40 °C). Upon adult emergence, 3- to 5-day-old female non-blood-fed mosquitoes were used for susceptibility tests following the World Health Organization (WHO) bioassay protocol. Batches of 20-25 mosquitoes from each temperature regime (25-34 °C) were exposed to two pyrethroid insecticides (0.75% permethrin and 0.05% deltamethrin). In addition, the levels of four metabolic enzymes (α-esterase, ß-esterase, glutathione S-transferase [GST], and mixed-function oxidase [MFO]) were examined in mosquitoes that were not exposed and those that were exposed to pyrethroids. RESULTS: Mortality in An. gambiae s.l. mosquitoes exposed to deltamethrin and permethrin decreased at temperatures above 28 °C. In addition, mosquitoes reared at higher temperatures were more resistant and had more elevated enzyme levels than those raised at low temperatures. Overall, mosquitoes that survived after being exposed to pyrethroids had higher levels of metabolic enzymes than those that were not exposed to pyrethroids. CONCLUSIONS: This study provides evidence that elevated temperatures decreased An. gambiae s.l. mosquitoes' susceptibility to pyrethroids and increased the expression of metabolic enzymes. This evidence suggests that elevated temperatures projected in a future warmer climate could increase mosquitoes' resistance to insecticides and complicate malaria vector control measures. This study therefore provides vital information, and suggests useful areas of future research, on the effects of temperature variability on mosquitoes that could guide vector control measures in a future warmer climate.


Assuntos
Anopheles , Inseticidas , Malária , Piretrinas , Animais , Esterases , Feminino , Resistência a Inseticidas , Inseticidas/farmacologia , Controle de Mosquitos/métodos , Mosquitos Vetores , Permetrina/farmacologia , Piretrinas/farmacologia , Temperatura
17.
Environ Monit Assess ; 194(6): 416, 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35536370

RESUMO

The use of imidacloprid and, to a lesser degree, other neonicotinoid insecticides is widespread in FL (and globally). The moderate to high water solubility and environmental persistence of neonicotinoids allows these compounds to readily enter, and be retained in, water resources where they may harm nontarget organisms and impact biological communities and associated trophic structures negatively. To better understand imidacloprid's chronic long-term exposure potential to aquatic invertebrate communities in FL, grab water samples were collected monthly in 2015 at 77 monitoring stations statewide. Fifty-eight stations (75%), representing 24 of the 25 drainage basins sampled, had detectable concentrations of imidacloprid, with concentrations ranging from 2 to 660 nanograms per liter [ng/L]. Imidacloprid basin medians were found to be correlated with two of six land use categories (urban, transportation, agriculture, and three crop classes) examined; urban (rho = 0.43, p-value = 0.03), and orchards and vineyards (rho 0.49, p-value = 0.01). The resampling of 12 select stations, representing eight basins, between August 2019 and July 2020, for the neonicotinoids acetamiprid, clothianidin, dinotefuran, imidacloprid, and thiamethoxam, showed that (1) median values of imidacloprid continued to exceed the US EPA chronic freshwater Invertebrate Aquatic Life Benchmark (IALB) (10 ng/L), (2) imidacloprid concentration was directly correlated with flow measurements, and (3) while median imidacloprid concentration decreased between the two sampling events (48.5 vs. 34.5 ng/L, p-value = 0.01) differences in event 1 and 2 streamflow regimes and disruptions due to the COVID-19 pandemic likely affected this outcome. Clothianidin was the only other neonicotinoid found to have values greater than a US EPA IALB, with detections at three stations exceeding the chronic IALB (50 ng/L). This study highlights the challenges associated with limiting neonicotinoids from entering water resources and identifies means to reduce their entry into and persistence within FL water resources.


Assuntos
COVID-19 , Inseticidas , Poluentes Químicos da Água , Animais , Monitoramento Ambiental , Florida , Humanos , Inseticidas/análise , Invertebrados , Neonicotinoides/análise , Nitrocompostos , Pandemias , Água
18.
Rev Soc Bras Med Trop ; 55: e03732021, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35522807

RESUMO

BACKGROUND: Aedes aegypti is currently controlled with synthetic larvicides; however, mosquitoes have become highly resistant to these larvicides and difficult to eradicate. Studies have shown that insecticides derived from fungal extracts have various mechanisms of action that reduce the risk of resistance in these mosquitoes. One possible mechanism is uncontrolled production of reactive oxygen species (ROS) in the larvae, which can cause changes at the cellular level. Thus, the crude extract of Xylaria sp. was evaluated to investigate the oxidative effect of this extract in A. aegypti larvae by quantifying the oxidative damage to proteins and lipids. METHODS: The larvicidal potential of the crude extract of Xylaria sp. Was evaluated, and the extract was subsequently tested in human lung fibroblasts for cytotoxicity and ROS production. ROS level was quantified in the larvae that were killed following exposure to the extract in the larvicide test. RESULTS: The crude extract of Xylaria sp. Caused cytotoxicity and induced ROS production in human lung fibroblasts and A. aegypti larvae, respectively. In the larvicide trial, the extract showed an LC50 of 264.456 ppm and an LC90 of 364.307 ppm, and was thus considered active. The extract showed greater oxidative damage to lipids and proteins, with LC90 values of 24.7 µmol MDA/L and 14.6278 ×10-3 nmol carbonyl/ mg protein, respectively. CONCLUSIONS: Crude extracts of Xylaria sp. induced oxidative stress that may have caused the mortality of A. aegypti larvae.


Assuntos
Aedes , Anopheles , Culex , Inseticidas , Animais , Humanos , Inseticidas/toxicidade , Larva , Lipídeos , Estresse Oxidativo , Extratos Vegetais/farmacologia , Folhas de Planta , Espécies Reativas de Oxigênio/farmacologia
19.
PLoS One ; 17(5): e0267278, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35536780

RESUMO

BACKGROUND: With the recent occurrence of locally transmitted Aedes-borne viruses in the continental United States and Europe, and a lack of effective vaccines, new approaches to control Aedes aegypti and Aedes albopictus are needed. In sub-tropical urban settings in the US, Ae. albopictus is a dominant nuisance and arbovirus vector species. Unfortunately, the vector control toolbox against Ae. albopictus is not as well developed as for Ae. aegypti. Here, we evaluate the efficacy, longevity, and range of protectiveness of a novel passive metofluthrin emanator (10% active ingredient in a polyethylene mesh) against Ae. albopictus indoors and outdoors. METHODS: Four studies were conducted comparing the presence of the metofluthrin emanator to a control lacking emanator with interest in quantifying efficacy by human landing counts. Studies evaluated the effect of an emanator at varying distances from one or more human volunteers indoors and outdoors. Efficacy of emanators over time since activation was also evaluated. RESULTS: Mixed-effects models determined that sitting in close proximity to an emanator reduced landings by 89.5% outdoors and by 74.6% indoors. The emanator was determined protective when located immediately next to a human volunteer outdoors but not uniformly protective when located further away. The emanator was protective at all tested distances from the device indoors. Mortality of mosquitoes exposed to metofluthrin emanators was ~2x higher than those who were not exposed in indoor conditions. Finally, a Generalized Additive Model determined that emanators used continuously outdoors lost their effect after 2.5 weeks and stopped inducing paralysis in mosquitoes after 3.8 weeks of use. CONCLUSIONS: We show strong and lasting efficacy of 10% metofluthrin emanators against field Ae. albopictus both in indoor and outdoor conditions. Metofluthrin emanators can protect people from Ae. albopictus bites, representing a viable option for reducing human-mosquito contacts at home and beyond.


Assuntos
Aedes , Inseticidas , Aedes/fisiologia , Animais , Ciclopropanos , Fluorbenzenos , Humanos , Inseticidas/farmacologia , Controle de Mosquitos , Mosquitos Vetores
20.
BMC Public Health ; 22(1): 930, 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35538444

RESUMO

BACKGROUND: The combined application of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are commonly used malaria interventions that target indoor Anopheles vectors. Recent studies on the effects of house screening (HS) and LLINs have demonstrated a reduction in indoor vector densities and malaria when the interventions are combined. In addition, complementary interventions are needed to curb co-occurring pest populations which pose menace to agricultural crop productivity and food security. However, interventions that impact malaria mainly centre on public health strategies, overlooking subtle but important component of agricultural measures. Addressing the coexisting risks of malaria and crop pests could contribute to improved livelihood of communities. METHODS: A four-armed household, cluster-randomized, controlled study will be conducted to assess the combined impact of HS, LLINs and push-pull agricultural technology (PPT) against clinical malaria in children in Ethiopia. The unit of randomization will be the household, which includes a house and its occupants. A total of 838 households will be enrolled in this study. In this trial 246 households will receive LLINs and HS, 250 will receive LLINs, HS and PPT, 175 households will receive LLINs and PPT. The remaining 167 houses which receive LLINs only will be used as control. One child aged ≤14 years will be enrolled per household in each treatment and followed for clinical malaria using active case detection to estimate malaria incidence for two malaria transmission seasons. DISCUSSION: Episodes of clinical malaria, density of indoor biting malaria vectors, sporozoite infection rate, improved crop infestation rate, crop yield gain, livestock productivity and cost effectiveness analysis will be the end points of this study. Socio-economic, social demographic, cost-effectiveness analysis will be conducted using qualitative and participatory methods to explore the acceptability of HS and PPT. Documenting the combined impact of LLINs, HS and PPT on the prevalence of clinical malaria and crop pest damage will be the first of its kind. TRIAL REGISTRATION: Pan African Clinical Trials Registry, PACTR202006878245287. 24/06/2020. https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=11101 .


Assuntos
Mosquiteiros Tratados com Inseticida , Inseticidas , Malária , Animais , Criança , Etiópia/epidemiologia , Humanos , Inseticidas/uso terapêutico , Malária/epidemiologia , Malária/prevenção & controle , Controle de Mosquitos/métodos , Mosquitos Vetores , Ensaios Clínicos Controlados Aleatórios como Assunto , Projetos de Pesquisa , Tecnologia
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