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1.
Braz. j. biol ; 83: e247676, 2023. tab, graf
Artigo em Inglês | 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
2.
Braz. j. biol ; 83: e240842, 2023. tab
Artigo em Inglês | 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
3.
Braz. j. biol ; 83: e248122, 2023. tab, graf
Artigo em Inglês | 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
4.
Braz. j. biol ; 83: e246230, 2023. tab, graf
Artigo em Inglês | 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
5.
Braz. j. biol ; 83: e247539, 2023. tab
Artigo em Inglês | 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
6.
Parasit Vectors ; 15(1): 326, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-36109765

RESUMO

BACKGROUND: Optimising insecticide use and managing insecticide resistance are important to sustain gains against malaria using long-lasting insecticidal nets (LLINs). Restricting insecticides to where mosquitoes are most likely to make multiple contacts could reduce the quantity of insecticide needed to treat the nets. Previous studies have shown that nets partially treated with a pyrethroid insecticide had equivalent mortality compared to a fully treated net. This study compared the efficacy of: (i) whole Interceptor® G2 nets (IG2; a dual-active LLIN containing alpha-cypermethrin and chlorfenapyr), (ii) nets with roof panels made of IG2 netting, (iii) nets with side panels made of IG2 netting and (iv) whole untreated nets as test nets. METHODS: The study was conducted in cow-baited experimental huts, Moshi Tanzania, using a four-arm Latin square design. Test nets had 30 holes cut in panels to simulate a typical net after 2-3 year use. The trial data were analysed using generalized linear models with mortality, blood-feeding, exophily and deterrence against wild free-flying Anopheles arabiensis as outcomes and test nets as predictors. RESULTS: Mortality was significantly higher in the nets with roof IG2 [27%, P = 0.001, odds ratio (OR) = 51.0, 95% CI = 4.8-546.2), side IG2 (44%, P < 0.001, OR = 137.6, 95% CI = 12.2-1553.2] and whole IG2 (53%, P < 0.001, OR = 223.0, 95% CI = 19.07-2606.0) nettings than the untreated (1%) nets. Mortality was also significantly higher in the whole IG2 net compared to the net with roof IG2 netting (P = 0.009, OR = 4.4, 95% CI = 1.4-13.3). Blood feeding was 22% in untreated, 10% in roof IG2, 14% in side IG2 and 19% in whole IG2 nets. Exiting was 92% in untreated, 89% in roof IG2, 97% in side IG2 and 94% whole IG2 nets. CONCLUSION: The results show that although the roof-treated IG2 net induced greater mortality compared to untreated nets, its efficacy was reduced compared to whole IG2 nets. Therefore, there was no benefit to be gained from restricting dual-active ingredient IG2 netting to the roof of nets.


Assuntos
Anopheles , Mosquiteiros Tratados com Inseticida , Inseticidas , Piretrinas , Animais , Bovinos , Feminino , Inseticidas/farmacologia , Macrolídeos , Controle de Mosquitos/métodos , Piretrinas/farmacologia , Tanzânia
7.
PLoS One ; 17(9): e0271427, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36084031

RESUMO

The "Magude project" aimed but failed to interrupt local malaria transmission in Magude district, southern Mozambique, by using a comprehensive package of interventions, including indoor residual spraying (IRS), pyrethroid-only long-lasting insecticide treated nets (LLINs) and mass-drug administration (MDA). Here we present detailed information on the vector species that sustained malaria transmission, their association with malaria incidence and behaviors, and their amenability to the implemented control interventions. Mosquitoes were collected monthly between May 2015 and October 2017 in six sentinel sites in Magude district, using CDC light traps both indoors and outdoors. Anopheles arabiensis was the main vector during the project, while An. funestus s.s., An. merus, An. parensis and An. squamosus likely played a secondary role. The latter two species have never previously been found positive for Plasmodium falciparum in southern Mozambique. The intervention package successfully reduced vector sporozoite rates in all species throughout the project. IRS was effective in controlling An. funestus s.s. and An. parensis, which virtually disappeared after its first implementation, but less effective at controlling An. arabiensis. Despite suboptimal use, LLINs likely provided significant protection against An. arabiensis and An. merus that sought their host largely indoors when people where in bed. Adding IRS on top of LLINs and MDA likely added value to the control of malaria vectors during the Magude project. Future malaria elimination attempts in the area could benefit from i) increasing the use of LLINs, ii) using longer-lasting IRS products to counteract the increase in vector densities observed towards the end of the high transmission season, and iii) a higher coverage with MDA to reduce the likelihood of human infection. However, additional interventions targeting vectors that survive IRS and LLINs by biting outdoors or indoors before people go to bed, will be likely needed to achieve local malaria elimination.


Assuntos
Anopheles , Mosquiteiros Tratados com Inseticida , Inseticidas , Malária , Piretrinas , Animais , Humanos , Inseticidas/farmacologia , Malária/epidemiologia , Malária/prevenção & controle , Controle de Mosquitos , Mosquitos Vetores
8.
Pak J Biol Sci ; 25(9): 816-821, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36098083

RESUMO

<b>Background and Objective:</b> Dengue cases have increased while the spread is getting broader worldwide. Temephos has been frequently used to control the larvae of the <i>Aedes aegypti</i> L., the primary vector of dengue. The intensive use of this larvicide has given rise to resistance. This study aims to determine the susceptibility status of <i>Ae. aegypti</i> to temephos and examine the two mutations (F290V and F455W) that possibly occur in the <i>Ace-1</i> gene of <i>Ae. aegypti</i> from Salido Sub-District, IV Jurai District, Pesisir Selatan Regency. <b>Materials and Methods:</b> The susceptibility test was performed referring to a standard method of the World Health Organization, followed by a molecular test (polymerase chain reaction) and sequencing. <b>Results:</b> The results showed that the larvae of <i>Ae. aegypti</i> have been tolerant to temephos (0.012 mg L<sup></sup><sup>1</sup>) with a percentage of larval mortality of 91.67%. The sequencing analysis in the <i>Ace-1</i> gene revealed the absence of F290V and F455W mutation in temephos-resistant <i>Ae. aegypti</i>, but a point mutation was detected at codon 506. This mutation shifts the ACA codon to ACT, but still codes for the same amino acid, threonine. <b>Conclusion:</b> Our study indicates the presence of other resistance mechanisms in the major dengue vector of the Salido District. Implementation of the alternative population control strategy is required to prevent the temephos resistance further.


Assuntos
Aedes , Dengue , Inseticidas , Aedes/genética , Animais , Indonésia , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Larva/genética , Mosquitos Vetores/genética , Mutação , Temefós
9.
Pak J Biol Sci ; 25(8): 688-697, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36098194

RESUMO

<b>Background and Objective:</b> In recent years, nanoemulsions have been used to target pest toxicity due to the dangers of chemical pesticides. The current study investigated the insecticidal activity of the mandarin crust oil (<i>Citrus reticulata</i>) and marigold extract (<i>Calendula officinalis </i>L.) in the form of nanoemulsions formulations and plant oil against 2nd instars larvae of <i>Spodoptera littoralis</i>. (Boisduval). <b>Materials and Methods:</b> To assess the toxicity of treatments to 2nd instar larvae, the leaf-dipping technique was used. The toxicity was recorded after one, three, five and seven days post-treatment and LC<sub>50</sub> values were calculated. <b>Results:</b> The results indicated that nanoemulsion of plant oil extracts has the highest insecticidal activity against <i>S. littoralis</i>, followed by plant oil extracts. The major constituents identified by GC-MS analysis in marigold extract and mandarin crust oil were, 6-epi-shyobunol (Longiborneol) and D-Limonene, respectively. Furthermore, at LC<sub>50</sub>, all treatments decreased AST/GOT and ALT/GPT activity, showing a significant reduction in creatinine activity when compared to control. <b>Conclusion:</b> According to the current study, the use of the nanoemulsion formulation could be useful in integrated pest management programs.


Assuntos
Inseticidas , Animais , Inseticidas/farmacologia , Larva , Extratos Vegetais/farmacologia , Óleos Vegetais/farmacologia , Spodoptera
10.
J Vis Exp ; (186)2022 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-36094286

RESUMO

As a vital vector of dengue fever, yellow fever, and other mosquito-borne diseases, Aedes albopictus (Diptera: Culicidae) can be broadly distributed worldwide and cause a severe threat to public health. To date, considering the fast-emerging insecticide resistance in the mosquito, the development of new botanical insecticides to control and reduce Ae. albopictus is urgent and crucial. Therefore, to investigate the decoction effect of the plant C. abrotanoides L. on mosquito larvae killing, we detected the mortality of larvae after treatment with different concentrations (60 mg/mL, 120 mg/mL, and 180 mg/mL) of decoction within a series of time points (12 h, 24 h, 36 h, and 48 h). We found that 24 h with 180 mg/mL C. abrotanoides L. decoction treatment killed 92.35% of mosquitoes relative to the control treatment. Meanwhile, 36 h with 120 mg/mL could also kill more than 90% of mosquitoes. Furthermore, Carassius auratus populations were exposed to 120 mg/mL C. abrotanoides L. decoction for 36 h and were not dead. The mortality evaluation indicated that this concentration is not a harmful level of ecological environmental pollution. This study provides a possible plant candidate that could be used for designing plant-derived insecticides. Additionally, these methods can be altered and applied to other mosquito species.


Assuntos
Aedes , Asteraceae , Inseticidas , Animais , Inseticidas/farmacologia , Larva , Mosquitos Vetores
11.
PLoS One ; 17(9): e0273851, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36074788

RESUMO

Neonicotinoid insecticides applied to flowering crops can have negative impacts on bees, with implications for crop pollination. To assess if exposure to the neonicotinoid clothianidin via a treated crop (rapeseed) affected bee behaviour, pollination performance (to strawberry), and bee reproduction, we provided each of 12 outdoor cages with rapeseed (autumn-sown plants complemented with a few spring-sown plants to extend the flowering period) grown from either clothianidin-treated or untreated (control) seeds, together with strawberry plants and a small population of red mason bees (Osmia bicornis). We expected clothianidin to reduce bee foraging activity, resulting in impaired strawberry pollination and bee reproduction. During the early stage of the experiment, we observed no difference between treatments in the length of entire foraging trips, or the combined number of rapeseed and strawberry flowers that the bees visited during these trips. During the later stage of the experiment, we instead determined the time a female took to visit 10 rapeseed flowers, as a proxy for foraging performance. We found that they were 10% slower in clothianidin cages. Strawberries weighed less in clothianidin cages, suggesting reduced pollination performance, but we were unable to relate this to reduced foraging activity, because the strawberry flowers received equally many visits in the two treatments. Clothianidin-exposed females sealed their nests less often, but offspring number, sex ratio and weight were similar between treatments. Observed effects on bee behaviour appeared by the end of the experiment, possibly because of accumulated effects of exposure, reduced bee longevity, or higher sensitivity of the protocols we used during the later phase of the experiment. Although the lack of a mechanistic explanation calls for interpreting the results with cautiousness, the lower strawberry weight in clothianidin cages highlights the importance of understanding complex effects of plant protection products, which could have wider consequences than those on directly exposed organisms.


Assuntos
Brassica napus , Brassica rapa , Fragaria , Inseticidas , Animais , Abelhas , Feminino , Flores/química , Guanidinas , Inseticidas/farmacologia , Neonicotinoides/toxicidade , Polinização , Sementes/química , Tiazóis
12.
Pestic Biochem Physiol ; 187: 105181, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36127043

RESUMO

Resistance of Tribolium castaneum to phosphine is related to point mutations in DNA code corresponding to amino acid changes associated with a core metabolic enzyme dihydrolipoamide dehydrogenase (DLD), but the mutation patterns vary among different resistant populations. Thus, there is a great need to develop a cost-effective method to detect core mutations in T. castaneum, which would be the key factor to understand the molecular basis of phosphine resistance. Amplification refractory mutation system-based quantitative Real-Time PCR (ARMS-qPCR) is an ideal method that can rapidly detect point mutations. Here, the P45S and G131D mutations existed in the DLD of T. castaneum selected from strong Chinese resistance phenotypes, and the DLD P45S mutation, which represents a strong phosphine resistance allele, was confirmed as the most abundant mutation to determine strong resistance genotypes. Our study found that 85 out of 120 beetles carried the P45S resistance allele, including 51 homozygous and 34 heterozygous individuals. Moreover, there was a strong linear relationship (R2 = 0.917) between the resistance ratio and the resistance allele frequency among the strongly resistant populations. Our data showed that the ARMS-qPCR method that we developed could rapidly determine strong resistance phenotypes of T. castaneum to phosphine by detecting the DLD P45S mutation. These results not only provide a detailed example for developing an ARMS-qPCR-based method to characterize pesticide resistance, but also support further elucidation of the molecular basis of phosphine resistance.


Assuntos
Inseticidas , Tribolium , Aminoácidos , Animais , Di-Hidrolipoamida Desidrogenase/genética , Di-Hidrolipoamida Desidrogenase/metabolismo , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mutação , Fosfinas , Reação em Cadeia da Polimerase em Tempo Real , Tribolium/genética , Tribolium/metabolismo
13.
Pestic Biochem Physiol ; 187: 105186, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36127048

RESUMO

The house fly (Musca domestica L.) (Diptera: Muscidae) is a global vector that can transmit >250 human and animal diseases. The control of house flies has heavily relied on the application of various chemical insecticides. The carbamate insecticide propoxur has been widely used for the control of house flies, and resistance to propoxur has been documented in many house fly populations worldwide. Previous studies have identified several propoxur resistance-conferring mutations in the target protein acetylcholinesterase; however, the molecular basis for metabolic resistance to propoxur remains unknown. In this study, we investigated the involvement of CYP6G4, a cytochrome P450 overexpressed in many insecticide resistant populations of Musca domestica, in propoxur metabolism and resistance by using combined approaches of recombinant protein-based insecticide metabolism and the Drosophila GAL4/UAS transgenic system. The recombinant CYP6G4 and its redox partners (NADPH-dependent cytochrome P450 reductase and cytochrome b5) were functionally expressed in Escherichia coli. Metabolism experiments showed that CYP6G4 was able to transform propoxur with a turnover rate of around 0.79 min-1. Six metabolites were putatively identified, suggesting that CYP6G4 could metabolize propoxur via hydroxylation, O-depropylation and N-demethylation. Moreover, bioassay results showed that ectopic overexpression of CYP6G4 in fruit flies significantly increased their tolerance to propoxur. Our in vivo and in vitro data convincingly demonstrate that CYP6G4 contributes to propoxur metabolism and resistance.


Assuntos
Moscas Domésticas , Inseticidas , Muscidae , Acetilcolinesterase/genética , Animais , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Citocromos b5 , Escherichia coli , Moscas Domésticas/genética , Humanos , Resistência a Inseticidas/genética , Inseticidas/farmacologia , NADP , NADPH-Ferri-Hemoproteína Redutase , Propoxur/farmacologia , Proteínas Recombinantes
14.
Pestic Biochem Physiol ; 187: 105187, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36127049

RESUMO

Sulfoxaflor (Isoclast™ active) is a sulfoximine insecticide that is active on a broad range of sap-feeding insects, including species that exhibit reduced susceptibility to currently available insecticides. Colonies of Myzus persicae (green peach aphid) were established from aphids collected in the field from peach (Prunus persica) and nectarine (Prunus persica var. nucipersica) orchards in France, Italy and Spain. The presence of the nicotinic acetylcholine receptor (nAChR) point mutation R81T was determined for all the colonies. Eight of the 35 colonies collected were susceptible relative to R81T (i.e., R81T absent), three of the colonies were found to be homozygous for R81T while 24 colonies had R81T present in some proportion (heterozygous). Sulfoxaflor and imidacloprid were tested in the laboratory against these M. persicae field colonies, which exhibited a wide range of susceptibilities (sulfoxaflor RR = 0.6 to 61, imidacloprid RR = 0.7 to 986) (resistance ratios, RR) to both insecticides. Although sulfoxaflor was consistently more active than imidacloprid against these field collected M. persicae, there was a statistically significant correlation across all colonies between the RRs for imidacloprid and sulfoxaflor (Pearson's r = 0.939, p < 0.0001). However, when a larger group of the colonies from Spain possessing R81T were analyzed, there was no correlation observed for the RRs between imidacloprid and sulfoxaflor (r = 0.2901, p = 0.3604). Thus, consistent with prior studies, the presence of R81T by itself is not well correlated with altered susceptibility to sulfoxaflor. In field trials, sulfoxaflor (24 and 36 gai/ha) was highly effective (~avg. 88-96% control) against M. persicae, demonstrating similar levels of efficacy as flonicamid (60-70 gai/ha) and spirotetramat (100-180 gai/ha) at 13-15 days after application, in contrast to imidacloprid (110-190 gai/ha) and acetamiprid (50-75 gai/ha) with lower levels of efficacy (~avg. 62-67% control). Consequently, sulfoxaflor is an effective tool for use in insect pest management programs for M. persicae. However, it is recommended that sulfoxaflor be used in the context of an insecticide resistance management program as advocated by the Insecticide Resistance Action Committee involving rotation with insecticides possessing other modes of action (i.e., avoiding rotation with other Group 4 insecticides) to minimize the chances for resistance development and to extend its future utility.


Assuntos
Afídeos , Inseticidas , Receptores Nicotínicos , Animais , Afídeos/genética , Inseticidas/farmacologia , Mutação , Neonicotinoides , Nitrocompostos , Piridinas , Receptores Nicotínicos/genética , Compostos de Enxofre
15.
Pestic Biochem Physiol ; 187: 105217, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36127059

RESUMO

Isocycloseram is a novel isoxazoline insecticide and acaricide with activity against lepidopteran, hemipteran, coleopteran, thysanopteran and dipteran pest species. Isocycloseram selectively targets the invertebrate Rdl GABA receptor at a site that is distinct to fiproles and organochlorines. The widely distributed cyclodiene resistance mutation, A301S, does not affect sensitivity to isocycloseram, either in vitro or in vivo, demonstrating the suitability of isocylsoseram to control pest infestations with this resistance mechanism. Detailed studies demonstrated that the binding sites relevant to the insecticidal activity of avermectins and isocycloseram are distinct. Isocycloseram was shown to compete for binding with metadiamide insecticides related to broflanilide. In addition, a G335M mutation in the third transmembrane domain of the Rdl GABA receptor, impaired the ability of both isocycloseram and metadiamides to block the GABA mediated response. As such the Insecticides Resistance Action Committee (IRAC) has classified isocycloseram in Group 30 "GABA-Gated Chloride Channel Allosteric Modulators".


Assuntos
Acaricidas , Inseticidas , Canais de Cloreto , Inseticidas/farmacologia , Receptores de GABA/genética , Ácido gama-Aminobutírico
16.
Pestic Biochem Physiol ; 187: 105218, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36127060

RESUMO

The Chinese wheat aphid Sitobion miscanthi (CWA) is an important harmful pest in wheat fields. Imidacloprid plays a critical role in controlling pests with sucking mouthparts. However, imidacloprid-resistant pests have been observed after insecticide overuse. Point mutations and low expression levels of the nicotinic acetylcholine receptor ß1 (nAchRß1) subunit are the main imidacloprid-resistant mechanisms. However, the regulatory mechanism underlying nAChRß1 subunit expression is poorly understood. In this study, a target of miR-263b was isolated from the 5'UTR of the nAchRß1 subunit in the CWA. Low expression levels were found in the imidacloprid-resistant strain CWA. Luciferase reporter assays showed that miR-263b could combine with the 5'UTR of the nAChRß1 subunit and suppress its expression by binding to a site in the CWA. Aphids treated with the miR-263b agomir exhibited a significantly reduced abundance of the nAchRß1 subunit and increased imidacloprid resistance. In contrast, aphids treated with the miR-263b antagomir exhibited significantly increased nAchRß1 subunit abundance and decreased imidacloprid resistance. These results provide a basis for an improved understanding of the posttranscriptional regulatory mechanism of the nAChRß1 subunit and further elucidate the function of miRNAs in regulating susceptibility to imidacloprid in the CWA. These results provide a better understanding of the mechanisms of posttranscriptional regulation of nAChRß1 and will be helpful for further studies on the role of miRNAs in the regulation of nAChRß1 subunit resistance in homopteran pests.


Assuntos
Afídeos , Inseticidas , MicroRNAs , Receptores Nicotínicos , Regiões 5' não Traduzidas , Animais , Antagomirs , Afídeos/genética , Afídeos/metabolismo , Resistência a Inseticidas/genética , Inseticidas/farmacologia , MicroRNAs/genética , Neonicotinoides , Nitrocompostos , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo
17.
Pestic Biochem Physiol ; 187: 105191, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36127065

RESUMO

Spinosyn insecticides (spinosad and spinetoram) have been widely used to control a number of agricultural pests including the fall armyworm, Spodoptera frugiperda. Mutations of the nicotinic acetylcholine receptor α6 subunit (nAChRα6) have been reported to confer high levels of resistance to spinosyns in several insect pests. Here we used CRISPR-mediated gene knockout to determine the involvement of S. frugiperda nAChRα6 (Sfα6) in spinosyns susceptibility. A Sfα6 knockout strain of S. frugiperda (Sfα6-KO) was established using dual single guide RNA (sgRNA) directed large fragment deletion with the CRISPR/Cas9 system. Sfα6-KO showed high levels of resistance to spinosad (307-fold) and spinetoram (517-fold) compared with the progenitor strain YJ-19, while no resistance was observed to emamectin benzoate, indoxacarb, chlorfenapyr, chlorantraniliprole and broflanilide. Genetic analyses confirmed that spinosad resistance in Sfα6-KO was autosomal, incompletely recessive and tightly linked to the edited deletion mutation of Sfα6. Our results provided in vivo functional evidence for Sfα6 as the major target of spinosyns against S. frugiperda, and demonstrated that disruption of Sfα6 causes high level resistance to spinosyns. Although no mutations of Sfα6 have yet been reported in any field populations of S. frugiperda, it is critical to develop F1 screens and/or DNA-based methods to detect and monitor the mutant allele frequencies of Sfα6 across global populations of S. frugiperda.


Assuntos
Inseticidas , Receptores Nicotínicos , Animais , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Macrolídeos , RNA Guia , Receptores Nicotínicos/genética , Spodoptera/genética
18.
Pestic Biochem Physiol ; 187: 105194, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36127066

RESUMO

Chlorantraniliprole (CAP), a representative bisamide insecticide, is widely used in rice fields around the world, posing potential toxicity risks to aquatic organisms. In this study, we examined the effects of exposure to CAP on growth and metabolic phenotype of zebrafish (Danio rerio) and oxidative stress and apoptosis in the liver of zebrafish (Danio rerio). First, we identified that CAP had a low bioaccumulation in zebrafish. Subsequently, growth phenotype analysis revealed that CAP could significantly increase liver weight and liver index in zebrafish. In addition, we found that CAP exposure could cause significant changes in indicators of oxidative stress, resulting in a significant increase in the content of malondialdehyde (MDA), causing oxidative stress in the liver of zebrafish. Meanwhile, the expression levels of apoptosis-related genes were also significantly changed and apoptosis was promoted in the liver of zebrafish with CAP exposure. Importantly, the results of metabolomics analysis shown that CAP exposure could significantly disrupt the metabolic phenotype of zebrafish, interfering with multiple metabolic pathways, mainly including valine, leucine and isoleucine biosynthesis and degradation, alanine, aspartate and glutamate metabolism and d-glutamine and D-glutamate metabolism. Last but not least, correlation analysis identified strong links between changes in liver function involving oxidative stress and apoptosis and changes in metabolic phenotype of zebrafish following CAP exposure. In brief, these results indicate that potential environmental risks of CAP to aquatic organisms should receive more attention.


Assuntos
Inseticidas , Poluentes Químicos da Água , Alanina/metabolismo , Animais , Ácido Aspártico/genética , Ácido Aspártico/metabolismo , Ácido Aspártico/farmacologia , Ácido Glutâmico , Glutamina/genética , Glutamina/metabolismo , Glutamina/farmacologia , Inseticidas/farmacologia , Isoleucina/genética , Isoleucina/metabolismo , Isoleucina/farmacologia , Leucina , Fígado , Malondialdeído/metabolismo , Fenótipo , Valina/farmacologia , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/genética , ortoaminobenzoatos
19.
Pestic Biochem Physiol ; 187: 105209, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36127073

RESUMO

Insecticide resistance monitoring is essential in assessing the efficacy of vector control measures. However, gold standard PCR-based molecular analyses for insecticide resistance detection are often hindered by time-consuming sample processing, as well as considerable infrastructure and resourcing requirements. In this study, we combined a novel one-step sample preparation reagent with a rapid isothermal molecular test that detects a knock down resistance (kdr) mutation (F1534C) that enables pyrethroid resistance in Aedes aegypti mosquitoes. We trialled the rapid F1534C pyrethroid resistance test using insecticide resistant Ae. aegypti mosquito bodies and compared results to a conventional, allele-specific quantitative PCR (AS-qPCR) coupled with melt curve genotyping in corresponding mosquito heads. From a strain of Ae. aegypti established from an insecticide resistant population in Merida, Mexico (n = 27), all the mosquito bodies (n = 27) tested positive with the rapid F1534C test regardless of whether they were homozygous or heterozygous. To assess diagnostic test specificity, we confirmed that F1534 was not detected in laboratory-reared, fully susceptible Ae. aegypti mosquito bodies (n = 28) using the rapid F1534C test or the conventional AS-qPCR melt curve analysis. All corresponding mosquito heads (n = 28) were homozygous wild-type FF1534. The rapid F1534C test thus demonstrated 100% diagnostic sensitivity (95% CI: 87.23% to 100%) and 100% diagnostic specificity (95% CI: 87.66% to 100.00%) for detection of the F1534C pyrethroid resistant single nucleotide polymorphism (SNP) in both heterozygous and homozygous Ae. aegypti. In the collection of mutant mosquitoes from Mexico, CC1534 homozygous mutants occurred at a frequency of 74.1% (n = 20) and FC heterozygous mutants at a frequency of 25.9% (n = 7). The rapid F1534C test significantly reduced the sample processing and testing time from approximately 6 h for the AS-qPCR melt curve analysis to only 25 min. These results demonstrate significant potential for our approach to resistance testing as a field-based, low-resource, rapid alternative to time-consuming and expensive laboratory-based detection.


Assuntos
Aedes , Inseticidas , Piretrinas , Aedes/genética , Animais , Inseticidas/farmacologia , Mosquitos Vetores/genética , Mutação , Piretrinas/farmacologia , Recombinases/genética
20.
PLoS One ; 17(9): e0274204, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36074780

RESUMO

The recently discovered insecticidal protein Mpp75Aa1.1 from Brevibacillus laterosporus is a member of the ETX_MTX family of beta-pore forming proteins (ß-PFPs) expressed in genetically modified (GM) maize to control western corn rootworm (WCR; Diabrotica virgifera virgifera LeConte). In this manuscript, bioinformatic analysis establishes that although Mpp75Aa1.1 shares varying degrees of similarity to members of the ETX_MTX2 protein family, it is unlikely to have any allergenic, toxic, or otherwise adverse biological effects. The safety of Mpp75Aa1.1 is further supported by a weight of evidence approach including evaluation of the history of safe use (HOSU) of ETX_MTX2 proteins and Breviballus laterosporus. Comparisons between purified Mpp75Aa1.1 protein and a poly-histidine-tagged (His-tagged) variant of the Mpp75Aa1.1 protein demonstrate that both forms of the protein are heat labile at temperatures at or above 55°C, degraded by gastrointestinal proteases within 0.5 min, and have no adverse effects in acute mouse oral toxicity studies at a dose level of 1920 or 2120 mg/kg body weight. These results support the use of His-tagged proteins as suitable surrogates for assessing the safety of their non-tagged parent proteins. Taken together, we report that Mpp75Aa1.1 is the first ETX-MTX2 insecticidal protein from B. laterosporus and displays a similar safety profile as typical Cry proteins from Bacillus thuringiensis.


Assuntos
Bacillus thuringiensis , Besouros , Inseticidas , Animais , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/metabolismo , Brevibacillus , Besouros/genética , Endotoxinas/metabolismo , Inseticidas/farmacologia , Larva/metabolismo , Camundongos , Controle Biológico de Vetores/métodos , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Zea mays/genética , Zea mays/metabolismo
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