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1.
J Vector Borne Dis ; 2023 Jan; 60(1): 79-87
Article | IMSEAR | ID: sea-216906

ABSTRACT

Background & objectives: Nanotechnology, an emerging field, has acquired considerable attention for the control of vectors. The present study aimed to synthesize, characterize copper sulfide- and eucalyptus oil-based hybrid nanoemulsions and investigate their larvicidal potential against Aedes aegypti by studying larvicidal bioassay, morphological aberrations, histopathological alterations, biochemical analysis and evaluation of risk assessment in non-target organisms. Methods: Hybrid nanoemulsions were prepared by mixing aqueous copper sulfide nanoparticles (CuSNPs) with non-polar eucalyptus oil in five ratios (1:1, 1:2, 1:3, 1:4 and 1:5) by sonication, screened and characterized using Transmission electron microscopy (TEM). Larvicidal activity was recorded and toxicity values were calculated by log-probit method. Morphological, histological and biochemical changes were examined in Aedes aegypti larvae after treatment. Nanohybrids were also tested under simulated conditions and against non-target organism. Results: The nanohybrid ratio of 1:5 was found to be stable after thermodynamic stability tests. TEM studies revealed average size of 90±7.90 nm with globular shape. LC50 and LC90 toxicity values of prepared CuSNPs were calculated out to be 5.00 and 5.81ppm after 24 hours treatment. Effective concentration of prepared nanohybrid (6.5ppm) tested under simulated conditions showed maximum larvicidal mortality after 48 hours of exposure. No toxicity towards the Mesocyclops spp. was observed after treatment of these nanohybrids even up to 21 days. Interpretation & conclusion: Copper sulfide based hybrid nanoemulsions were found to show efficient larvicidal property which can be used for the formulation of ecofriendly bio-larvicide against Aedes aegypti.

2.
Braz. j. biol ; 83: e246230, 2023. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1339369

ABSTRACT

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.


Subject(s)
Humans , Animals , Aedes , Fusarium , Insecticides/pharmacology , Pakistan , Soil , Plant Extracts , Forests , Mosquito Vectors , Larva
3.
Braz. j. biol ; 83: e240842, 2023. tab
Article in English | LILACS, VETINDEX | ID: biblio-1339375

ABSTRACT

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.


Subject(s)
Animals , Culex , Chenopodium , Insecticides/pharmacology , Plant Extracts/pharmacology , Plant Leaves , Hexanes , Larva
4.
Arq. ciências saúde UNIPAR ; 27(9): 4962-4974, 2023.
Article in Portuguese | LILACS-Express | LILACS | ID: biblio-1509535

ABSTRACT

Aedes aegypti (Diptera: Culicidae) é o principal vetor das arboviroses dengue, zika, chikungunya e febre amarela. A busca por inseticidas naturais para combater o mosquito ganha destaque nos países de clima tropical. Considerando a atividade larvicida presente no gênero Monteverdia o objetivo do estudo foi avaliar o potencial larvicida dos extratos e frações da espécie Monteverdia evonymoides (Reissek) Biral. O material vegetal (folhas e galhos) foi seco a temperatura ambiente, foi moído e submetido a extração em Soxhlet modificado. A toxicidade foi avaliada por meio do bioensaio com Artemia salina L. As larvas de Aedes aegypti foram expostas nas concentrações 10, 100, 500 e 1000 µg.mL⁻¹. Após 24H foi realizada a leitura da mortalidade (CL50) e submetido método estatístico Probit. As amostras não apresentaram toxicidade frente a Artemia salina L. (>1000 µg.mL⁻¹) e apresentaram potencial larvida no controle de larvas de terceiro estádio, com CL50 >200 µg.mL⁻¹. Os extratos de M. Evonymoides são seguros e apresentaram potencial larvicida contra larvas do mosquito.


Aedes aegypti (Diptera: Culicidae) is the main vector of arboviruses den- gue, zika, chikungunya and yellow fever. The search for natural insecticides to combat the mosquito is highlighted in countries with a tropical climate. Considering the larvicidal activity present in the genus Monteverdia, the objective of the study was to evaluate the larvicidal potential of extracts and fractions of the species Monteverdia evonymoides (Reissek) Biral. The plant material (leaves and branches) was dried at room temperature, ground and subjected to extraction in modified Soxhlet. Toxicity was evaluated by bio- assay with Artemia salina L. Aedes aegypti larvae were exposed to concentrations of 10, 100, 500 and 1000 µg.mL⁻¹. After 24 hours, the mortality reading (CL50) was performed and the Probit statistical method was submitted. The samples did not show toxicity against Artemia salina L. (>1000 µg.mL⁻¹) and showed potential larval life in the control of third- stage larvae, with CL50 >200 µg.mL⁻¹. M. Evonymoides extracts are safe and showed lar- vicidal potential against mosquito larvae.


Aedes aegypti (Diptera: Culicidae) es el principal vector de los arbovirus dengue, zika, chikungunya y fiebre amarilla. Se destaca la búsqueda de insecticidas natu- rales para combatir el mosquito en países con clima tropical. Considerando la actividad larvicida presente en el género Monteverdia, el objetivo del estudio fue evaluar el poten- cial larvicida de extractos y fracciones de la especie Monteverdia evonymoides (Reissek) Biral. El material vegetal (hojas y ramas) fue secado a temperatura ambiente, molido y sometido a extracción en Soxhlet modificado. La toxicidad se evaluó mediante el bioen- sayo con Artemia salina L. Se expusieron larvas de Aedes aegypti a concentraciones de 10, 100, 500 y 1000 µg.mL⁻¹. A las 24 horas se realizó la lectura de mortalidad (CL50) y se sometió al método estadístico Probit. Las muestras no presentaron toxicidad contra Artemia salina L. (>1000 µg.mL⁻¹) y mostraron potencial de vida larvaria en el control de larvas de tercer estadio, con CL50 >200 µg.mL⁻¹. Los extractos de M. Evonymoides son seguros y mostraron potencial larvicida contra las larvas de mosquitos.

5.
Braz. j. biol ; 83: 1-7, 2023. ilus, tab
Article in English | LILACS, VETINDEX | ID: biblio-1468917

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 3.8x108, 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.


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 [...].


Subject(s)
Animals , Aedes , Pest Control, Biological/methods , Fusarium/isolation & purification , Fusarium/pathogenicity
6.
Braz. j. biol ; 83: 1-11, 2023. tab
Article in English | LILACS, VETINDEX | ID: biblio-1468934

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.


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.


Subject(s)
Animals , Chenopodium/chemistry , Mosquito Control/methods , Culex/growth & development
7.
Braz. j. biol ; 832023.
Article in English | LILACS-Express | LILACS, VETINDEX | ID: biblio-1469133

ABSTRACT

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.

8.
Braz. j. biol ; 832023.
Article in English | LILACS-Express | LILACS, VETINDEX | ID: biblio-1469150

ABSTRACT

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.

9.
J Vector Borne Dis ; 2022 Oct; 59(4): 320-326
Article | IMSEAR | ID: sea-216898

ABSTRACT

Background & objectives: Recently, the use of biodegradable and environment friendly plant-based bioinsecticides has received a great deal of attention from researchers to control insect disease vectors. The aim of this research is to determine the larvicidal efficacy of Ruta graveolens essential oil against third instar larvae of two species of mosquito (Culex pipiens and Culiseta longiareolata) and a biological model Drosophila melanogaster. Methods: Culiseta longiareolata and Culex pipiens larvae were collected from untreated areas located in Tebessa and Drosophila melanogaster, the wild strain collected from rotten apples in the Tebessa region. Ruta graveolens essential oil has been tested at different concentrations between 2.5µL/mL and 140µL/mL against third instar larvae of the three species under standard laboratory conditions according to the recommendations from the Word Health Organization. The effects were examined on mortality, growth and the main components (proteins, carbohydrates, lipids). Results: The essential oil showed larvicidal activity with LC50 and LC90 values (10.85µL/mL, 70.95µL/mL and 39.41µL/mL), (26.5µL/mL, 144.5µL/mL and 89.57µL/mL) against third instar larvae of Drosophila melanogaster, Culex pipiens and Culiseta longiareolata respectively. In addition, it disrupted the growth and several morphological malformations were observed. It also affected growth and the main components (proteins, carbohydrates, lipids). Interpretation & conclusion: The essential oil affected growth and energy reserves for all three species. The results indicated that the essential oil of Ruta graveolens has good potential as a source of natural larvicides.

10.
J Vector Borne Dis ; 2022 Jul; 59(3): 228-235
Article | IMSEAR | ID: sea-216890

ABSTRACT

Background & objectives: Transmission of dengue virus by Aedes aegypti mosquito is one of the major global health concerns. The present study was aimed to explore the larvicidal potential of oil extracted from kinnow peel waste to be used as an efficient, economic and safe agent against Ae. aegypti. Methods: Kinnow peel oil was extracted and its five concentrations at 40, 50, 60, 70 and 80 ppm were tested against 4th instar larvae of Ae. aegypti. Larval mortality (%) and LC50 and LC90 values of toxicity were determined followed by evaluation of the residual activity effect of its leftover effective concentration on larval mortality, development and emergence. Effect of storage (2, 4 and 6 months) on larvicidal potential of kinnow peel oil was also determined. Results: Out of the tested concentrations, 70 ppm of kinnow peel oil was found to be the effective concentration against 4th instar larvae of Ae. aegypti. LC50 and LC90 toxicity values were 47.26 and 61.56 ppm, respectively. No residual activity effect in terms of larval mortality was found, however a significant delay in development (L4 to adult) was observed after placing new larvae in the leftover effective oil concentration. No effect of storage on larvicidal potential of 2, 4 and 6 months old kinnow peel oil in comparison to freshly extracted oil was observed. Interpretation & conclusion: Kinnow peel oil proved to have a good potential as a biolarvicide against Ae. aegypti and could be used as an effective and eco-friendly mosquito control agent in the future.

11.
Braz. j. biol ; 82: e241338, 2022. tab
Article in English | LILACS, VETINDEX | ID: biblio-1278470

ABSTRACT

Mosquito-borne diseases result in the loss of life and economy, primarily in subtropical and tropical countries, and the emerging resistance to insecticides is increasing this threat. Botanical insecticides are promising substitutes for synthetic insecticides. This study evaluated the larvicidal and growth index of Culex pipiens of four solvent extracts of Terminalia chebula, Aloe perryi, and Peganum harmala against Cx. pipiens. None of the 12 extracts exhibited larvicidal potential against third instars except the ethyl acetate extract of P. harmala. After 24 h of exposure, the LC50 value was 314.88 ppm, and the LC90 value was 464.19 ppm. At 320 ppm, the hatchability was 25.83%, and it resulted in 100% mortality. In addition, the eggs treated with the EtOAc extract of P. Harmala exhibited a long larval period compared with the control. The larval period continued for 12 days, and the pupal period took three days in the treatment groups. The growth index data also exhibited a decrease (0.00­7.53) in the treated groups compare with 8.5 in the control. The transformation of eggs into adults decreased with increasing concentrations. This paper is the first report on the development and growth index of Cx. pipiens potential using P. harmala seeds.


As doenças transmitidas por mosquitos resultam na perda de vidas e economia, principalmente em países subtropicais e tropicais, e a resistência emergente aos inseticidas está aumentando essa ameaça. Os inseticidas botânicos são substitutos promissores dos inseticidas sintéticos. Este estudo avaliou o índice larvicida e de crescimento de Culex pipiens de quatro extratos solventes de Terminalia chebula, Aloe perryi e Peganum harmala contra Cx. pipiens. Nenhum dos 12 extratos exibiu potencial larvicida contra o terceiro ínstar, exceto o extrato de acetato de etila de P. harmala. Após 24 horas de exposição, o valor LC50 era 314,88 ppm e o valor LC90 era 464,19 ppm. A 320 ppm, a eclodibilidade foi de 25,83% e resultou em 100% de mortalidade. Além disso, os ovos tratados com o extrato de EtOAc de P. harmala exibiram um longo período larval em comparação com o controle. O período larval continuou por 12 dias, e o período pupal durou três dias nos grupos de tratamento. Os dados do índice de crescimento também exibiram uma diminuição (0,00-7,53) nos grupos tratados em comparação com 8,5 no controle. A transformação de ovos em adultos diminuiu com o aumento das concentrações. Este artigo é o primeiro relatório sobre o índice de desenvolvimento e crescimento de Cx. potencial de pipiens usando sementes de P. harmala.


Subject(s)
Animals , Aedes , Culex , Peganum , Insecticides , Anopheles , Seeds , Plant Extracts/pharmacology , Larva
12.
Braz. j. biol ; 82: e236498, 2022. tab
Article in English | LILACS, VETINDEX | ID: biblio-1153475

ABSTRACT

Mormodica charantia (Curcubitaceae) is a plant with great medicinal potential, also used as an alternative of mosquitoes control as demonstrated by previous studies. We evaluated the larvicidal activity of crude extracts of ethyl acetate, methanol and hexane from flowers and fruits of M. charantia against Aedes aegypti (Culicidae). Flowers and fruits were macerated in methanol, ethyl acetate and hexane. Bioassays were performed with application of the extracts at final concentrations of 1 - 200 µg/mL in the middle of the third instar larvae of A. aegypti (L3). The results showed high toxicity to ethyl acetate extracts from flowers and fruits at concentrations of 200 µg/mL and 100 µg/mL, with 97% and 87% of larvae mortality (L3), respectively. Hexane extract demonstrated low toxicity, while methanol extract exhibited 78% larval mortality. The data suggested that the ethyl acetate extracts of flowers and fruits of M. charantia can effectively contribute to larvicidal activity. In addition, purification of M. charantia extracts may lead to a promising larvicidal activity to control the A. aegypti population.


Mormodica charantia (Curcubitaceae) é uma planta com grande potencial medicinal, sendo também uma alternativa no controle de mosquitos conforme demonstrado por estudos prévios. Avaliou-se a atividade larvicida dos extratos brutos de acetato de etila, metanólico e hexânico das folhas, flores e frutos de M. charantia no Aedes aegypti (Culicidae). Folhas, flores e frutos foram macerados em metanol, acetato de etila e hexano. Os bioensaios foram realizados com aplicação dos extratos nas concentrações finais de 1-200 µg/mL no meio de criação das larvas de terceiro estádio de A. aegypti (L3). Os resultados obtidos apontaram alta toxicidade para os extratos de acetato de etila das flores e frutos nas concentrações de 200 µg/mL e 100 µg/mL com mortalidade em L3 de 96,7% e 87%, respectivamente. Baixa toxicidade para o extrato hexânico e o extrato metanólico apresentou mortalidade de 78% larval. Os dados sugerem que os extratos de acetato de etila das flores e frutos de M. charantia podem contribuir efetivamente para atividade larvicida no controle da população de A. aegypti.


Subject(s)
Animals , Aedes , Momordica charantia , Insecticides/pharmacology , Plant Extracts/pharmacology , Plant Leaves , Larva
13.
Braz. j. biol ; 82: 1-6, 2022. tab
Article in English | LILACS, VETINDEX | ID: biblio-1468432

ABSTRACT

Mormodica charantia (Curcubitaceae) is a plant with great medicinal potential, also used as an alternative of mosquitoes control as demonstrated by previous studies. We evaluated the larvicidal activity of crude extracts of ethyl acetate, methanol and hexane from flowers and fruits of M. charantia against Aedes aegypti (Culicidae). Flowers and fruits were macerated in methanol, ethyl acetate and hexane. Bioassays were performed with application of the extracts at final concentrations of 1 - 200 µg/mL in the middle of the third instar larvae of A. aegypti (L3). The results showed high toxicity to ethyl acetate extracts from flowers and fruits at concentrations of 200 µg/mL and 100 µg/mL, with 97% and 87% of larvae mortality (L3), respectively. Hexane extract demonstrated low toxicity, while methanol extract exhibited 78% larval mortality. The data suggested that the ethyl acetate extracts of flowers and fruits of M. charantia can effectively contribute to larvicidal activity. In addition, purification of M. charantia extracts may lead to a promising larvicidal activity to control the A. aegypti population.


Mormodica charantia (Curcubitaceae) é uma planta com grande potencial medicinal, sendo também uma alternativa no controle de mosquitos conforme demonstrado por estudos prévios. Avaliou-se a atividade larvicida dos extratos brutos de acetato de etila, metanólico e hexânico das folhas, flores e frutos de M. charantia no Aedes aegypti (Culicidae). Folhas, flores e frutos foram macerados em metanol, acetato de etila e hexano. Os bioensaios foram realizados com aplicação dos extratos nas concentrações finais de 1-200 µg/mL no meio de criação das larvas de terceiro estádio de A. aegypti (L3). Os resultados obtidos apontaram alta toxicidade para os extratos de acetato de etila das flores e frutos nas concentrações de 200 µg/mL e 100 µg/mL com mortalidade em L3 de 96,7% e 87%, respectivamente. Baixa toxicidade para o extrato hexânico e o extrato metanólico apresentou mortalidade de 78% larval. Os dados sugerem que os extratos de acetato de etila das flores e frutos de M. charantia podem contribuir efetivamente para atividade larvicida no controle da população de A. aegypti.


Subject(s)
Aedes , Larvicides/analysis , Momordica charantia/drug effects , Momordica charantia/toxicity
14.
Braz. j. biol ; 82: 1-6, 2022. tab
Article in English | LILACS, VETINDEX | ID: biblio-1468545

ABSTRACT

Mosquito-borne diseases result in the loss of life and economy, primarily in subtropical and tropical countries, and the emerging resistance to insecticides is increasing this threat. Botanical insecticides are promising substitutes for synthetic insecticides. This study evaluated the larvicidal and growth index of Culex pipiens of four solvent extracts of Terminalia chebula, Aloe perryi, and Peganum harmala against Cx. pipiens. None of the 12 extracts exhibited larvicidal potential against third instars except the ethyl acetate extract of P. harmala. After 24 h of exposure, the LC50 value was 314.88 ppm, and the LC90 value was 464.19 ppm. At 320 ppm, the hatchability was 25.83%, and it resulted in 100% mortality. In addition, the eggs treated with the EtOAc extract of P. Harmala exhibited a long larval period compared with the control. The larval period continued for 12 days, and the pupal period took three days in the treatment groups. The growth index data also exhibited a decrease (0.00–7.53) in the treated groups compare with 8.5 in the control. The transformation of eggs into adults decreased with increasing concentrations. This paper is the first report on the development and growth index of Cx. pipiens potential using P. harmala seeds.


As doenças transmitidas por mosquitos resultam na perda de vidas e economia, principalmente em países subtropicais e tropicais, e a resistência emergente aos inseticidas está aumentando essa ameaça. Os inseticidas botânicos são substitutos promissores dos inseticidas sintéticos. Este estudo avaliou o índice larvicida e de crescimento de Culex pipiens de quatro extratos solventes de Terminalia chebula, Aloe perryi e Peganum harmala contra Cx. pipiens. Nenhum dos 12 extratos exibiu potencial larvicida contra o terceiro ínstar, exceto o extrato de acetato de etila de P. harmala. Após 24 horas de exposição, o valor LC50 era 314,88 ppm e o valor LC90 era 464,19 ppm. A 320 ppm, a eclodibilidade foi de 25,83% e resultou em 100% de mortalidade. Além disso, os ovos tratados com o extrato de EtOAc de P. harmala exibiram um longo período larval em comparação com o controle. O período larval continuou por 12 dias, e o período pupal durou três dias nos grupos de tratamento. Os dados do índice de crescimento também exibiram uma diminuição (0,00-7,53) nos grupos tratados em comparação com 8,5 no controle. A transformação de ovos em adultos diminuiu com o aumento das concentrações. Este artigo é o primeiro relatório sobre o índice de desenvolvimento e crescimento de Cx. potencial de pipiens usando sementes de P. harmala.


Subject(s)
Animals , Culex/growth & development , Insecticides/administration & dosage , Peganum/adverse effects
15.
Braz. j. biol ; 822022.
Article in English | LILACS-Express | LILACS, VETINDEX | ID: biblio-1468619

ABSTRACT

Abstract Mormodica charantia (Curcubitaceae) is a plant with great medicinal potential, also used as an alternative of mosquitoes control as demonstrated by previous studies. We evaluated the larvicidal activity of crude extracts of ethyl acetate, methanol and hexane from flowers and fruits of M. charantia against Aedes aegypti (Culicidae). Flowers and fruits were macerated in methanol, ethyl acetate and hexane. Bioassays were performed with application of the extracts at final concentrations of 1 - 200 µg/mL in the middle of the third instar larvae of A. aegypti (L3). The results showed high toxicity to ethyl acetate extracts from flowers and fruits at concentrations of 200 µg/mL and 100 µg/mL, with 97% and 87% of larvae mortality (L3), respectively. Hexane extract demonstrated low toxicity, while methanol extract exhibited 78% larval mortality. The data suggested that the ethyl acetate extracts of flowers and fruits of M. charantia can effectively contribute to larvicidal activity. In addition, purification of M. charantia extracts may lead to a promising larvicidal activity to control the A. aegypti population.


Resumo Mormodica charantia (Curcubitaceae) é uma planta com grande potencial medicinal, sendo também uma alternativa no controle de mosquitos conforme demonstrado por estudos prévios. Avaliou-se a atividade larvicida dos extratos brutos de acetato de etila, metanólico e hexânico das folhas, flores e frutos de M. charantia no Aedes aegypti (Culicidae). Folhas, flores e frutos foram macerados em metanol, acetato de etila e hexano. Os bioensaios foram realizados com aplicação dos extratos nas concentrações finais de 1-200 µg/mL no meio de criação das larvas de terceiro estádio de A. aegypti (L3). Os resultados obtidos apontaram alta toxicidade para os extratos de acetato de etila das flores e frutos nas concentrações de 200 µg/mL e 100 µg/mL com mortalidade em L3 de 96,7% e 87%, respectivamente. Baixa toxicidade para o extrato hexânico e o extrato metanólico apresentou mortalidade de 78% larval. Os dados sugerem que os extratos de acetato de etila das flores e frutos de M. charantia podem contribuir efetivamente para atividade larvicida no controle da população de A. aegypti.

16.
Braz. j. biol ; 822022.
Article in English | LILACS-Express | LILACS, VETINDEX | ID: biblio-1468732

ABSTRACT

Abstract Mosquito-borne diseases result in the loss of life and economy, primarily in subtropical and tropical countries, and the emerging resistance to insecticides is increasing this threat. Botanical insecticides are promising substitutes for synthetic insecticides. This study evaluated the larvicidal and growth index of Culex pipiens of four solvent extracts of Terminalia chebula, Aloe perryi, and Peganum harmala against Cx. pipiens. None of the 12 extracts exhibited larvicidal potential against third instars except the ethyl acetate extract of P. harmala. After 24 h of exposure, the LC50 value was 314.88 ppm, and the LC90 value was 464.19 ppm. At 320 ppm, the hatchability was 25.83%, and it resulted in 100% mortality. In addition, the eggs treated with the EtOAc extract of P. Harmala exhibited a long larval period compared with the control. The larval period continued for 12 days, and the pupal period took three days in the treatment groups. The growth index data also exhibited a decrease (0.007.53) in the treated groups compare with 8.5 in the control. The transformation of eggs into adults decreased with increasing concentrations. This paper is the first report on the development and growth index of Cx. pipiens potential using P. harmala seeds.


Resumo As doenças transmitidas por mosquitos resultam na perda de vidas e economia, principalmente em países subtropicais e tropicais, e a resistência emergente aos inseticidas está aumentando essa ameaça. Os inseticidas botânicos são substitutos promissores dos inseticidas sintéticos. Este estudo avaliou o índice larvicida e de crescimento de Culex pipiens de quatro extratos solventes de Terminalia chebula, Aloe perryi e Peganum harmala contra Cx. pipiens. Nenhum dos 12 extratos exibiu potencial larvicida contra o terceiro ínstar, exceto o extrato de acetato de etila de P. harmala. Após 24 horas de exposição, o valor LC50 era 314,88 ppm e o valor LC90 era 464,19 ppm. A 320 ppm, a eclodibilidade foi de 25,83% e resultou em 100% de mortalidade. Além disso, os ovos tratados com o extrato de EtOAc de P. harmala exibiram um longo período larval em comparação com o controle. O período larval continuou por 12 dias, e o período pupal durou três dias nos grupos de tratamento. Os dados do índice de crescimento também exibiram uma diminuição (0,00-7,53) nos grupos tratados em comparação com 8,5 no controle. A transformação de ovos em adultos diminuiu com o aumento das concentrações. Este artigo é o primeiro relatório sobre o índice de desenvolvimento e crescimento de Cx. potencial de pipiens usando sementes de P. harmala.

17.
Braz. J. Pharm. Sci. (Online) ; 57: e18479, 2021. tab, graf
Article in English | LILACS | ID: biblio-1339305

ABSTRACT

The seed oil of Annona salzmannii A. DC. was analyzed by GC-MS and 1H qNMR, revealing a mixture of unsaturated (80.5%) and saturated (18.7%) fatty acids. Linoleic (45.3%) and oleic (33.5%) acid were the major unsaturated fatty acids identified, while palmitic acid (14.3%) was the major saturated fatty acid. The larvicidal effects of A. salzmannii seed oil were evaluated against third-instar larvae of Aedes aegypti (Linn.). The oil exhibited moderate larvicidal activity, with a LC50 of 569.77 ppm (95% CI = 408.11 to 825.88 ppm). However, when the cytotoxic effects of the oil were evaluated, no expressive antiproliferative effects were observed in tumor cell lines B16-F10 (mouse melanoma), HepG2 (human hepatocellular carcinoma), K562 (human chronic myelocytic leukemia), HL-60 (human promyelocytic leukemia), and non-tumor cell line PBMC (peripheral blood mononuclear cells), with IC50 values > 50 µg·mL-1. This is the first study to evaluate the chemical composition, larvicidal and cytotoxic activity of A. salzmannii seed oil


Subject(s)
Seeds/anatomy & histology , Plant Oils/analysis , Annonaceae/chemistry , Annona/adverse effects , Leukemia, Myelogenous, Chronic, BCR-ABL Positive , Fatty Acids, Unsaturated , Larva/classification
18.
Rev. Soc. Bras. Med. Trop ; 54: e08352020, 2021. graf
Article in English | LILACS | ID: biblio-1288107

ABSTRACT

Abstract INTRODUCTION: Bioprospection of plant products is used to discover new insecticides. METHODS: The larvicidal activity of ethanolic extract and triterpene (tingenone B) from the bark of Maytenus guianensis and their effect on pupation and emergence were evaluated against Aedes aegypti. RESULTS: Crude extract LC50 was 11.3 ppm and caused ejection of the larvae intestine; tingenone B LC50 was 14.8 ppm. Pupation was reduced by 20% and 10%, respectively; however, the emergence was not affected. CONCLUSIONS: The crude bark extract exhibited a higher larvicidal effect against the vector.


Subject(s)
Aedes , Celastraceae , Maytenus , Insecticides/pharmacology , Anopheles , Plant Extracts/pharmacology , Plant Leaves , Mosquito Vectors , Larva
19.
Rev. Soc. Bras. Med. Trop ; 54: e0576-2020, 2021. tab
Article in English | LILACS | ID: biblio-1155533

ABSTRACT

Abstract INTRODUCTION: Aedes aegypti is the main vector of dengue and yellow fever. Recently, the use of plant-sourced larvicides has gained momentum. METHODS: The hydroethanolic extracts and fractions ofOcotea nutansleaves and stems were bioassayed to determine the larvicidal efficacy of these samples. RESULTS: S-HEX (hexane fraction from the crude stem extract) demonstrated high potential for controlling third-stage larvae, with an LC50 of 14.14 µg.mL-1 (concentration required to inhibit 50% of the treated larvae). CONCLUSIONS Extracts from O. nutans were effective against third-stage larvae ofA. aegyptiafter 24 h of exposure.


Subject(s)
Animals , Aedes , Mosquito Vectors , Insecticides/pharmacology , Plant Extracts/pharmacology , Plant Leaves , Ocotea , Larva
20.
Tropical Biomedicine ; : 186-191, 2021.
Article in English | WPRIM | ID: wpr-904736

ABSTRACT

@#Plants contain bioactive compounds and are constantly explored as safer alternatives to conventional insecticides. Despite numerous studies on many plants, information on the insecticidal potential of underutilised plants like tiger nut, Cyperus esculentus L., are scant, although their pharmacological potentials are well known. Hence, this study investigated the larvicidal potential of crude aqueous extracts of two C. esculentus varieties (black and yellow) on the mosquitoes Aedes aegypti (L.) and Culex quinquefasciatus (Say). Mosquito larvae were exposed to C. esculentus crude extracts using the larval bioassay technique of the World Health Organization. Differential larvicidal responses were observed in the test mosquitoes and extracts of Black Dried Tiger nuts (BDT) were more larvicidal than Yellow Dried Tiger nuts (YDT). Acute larval toxicity of the extracts was more pronounced on Cx. quinquefasciatus than Ae. aegypti. The results indicate the potential of C. esculentus (particularly BDT) as a source of mosquito bioinsecticide and merits further studies as a safer alternative to conventional insecticide-based vector control.

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