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1.
J Basic Microbiol ; : e2400159, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38771084

RESUMO

Entomopathogenic fungi are the most effective control remedy against a wide range of medical and agricultural important pests. The present study aimed to isolate, identify, and assess the virulence of Metarhizium rileyi against Spodoptera litura and Spodoptera frugiperda pupae under soil conditions. The biotechnological methods were used to identify the isolate as M. rileyi. The fungal conidial pathogenicity (2.0 × 107, 2.0 × 108, 2.0 × 109, 2.0 × 1010, and 2.0 × 1011 conidia/mL-1) was tested against prepupae of S. litura and S. frugiperda at 3, 6, 9, and 12 days after treatments. Additionally, the artificial soil-conidial assay was performed on a nontarget species earthworm Eudrilus eugeniae, using M. rileyi conidia. The present results showed that the M. rileyi caused significant mortality rates in S. litura pupae (61-90%), and S. litura pupae were more susceptible than S. frugiperda pupae (46%-73%) at 12 day posttreatment. The LC50 and LC90 of M. rileyi against S. litura, were 3.4 × 1014-9.9 × 1017 conidia/mL-1 and 6.6 × 105-4.6 × 1014 conidia/mL-1 in S. frugiperda, respectively. The conidia of M. rileyi did not exhibit any sublethal effect on the adult stage of E. eugeniae, and Artemia salina following a 12-day treatment period. Moreover, in the histopathological evaluation no discernible harm was observed in the gut tissues of E. eugeniae, including the lumen and epithelial cells, as well as the muscles, setae, nucleus, mitochondria, and coelom. The present findings provide clear evidence that M. rileyi fungal conidia can be used as the foundation for the development of effective bio-insecticides to combat the pupae of S. litura and S. frugiperda agricultural pests.

2.
Toxicon ; 243: 107737, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38677379

RESUMO

Botanical essential oils are natural insecticides derived from plants, offering eco-friendly alternatives to synthetic chemicals for pest control. In this study, the essential oils were extracted from Acacia nilotica seed cotyledons, and their toxicity was tested against insect pests. Furthermore, the chemical components of the essential oils were identified through gas chromatography-mass spectrometry (GC-MS) analysis. The essential oil extracted from A. nilotica seeds exhibited the highest mortality rates of 60% and 98% in Culex quinquefasciatus, and 60% and 96.66% mortality in Plutella xylostella at 24 and 48 h after treatment, respectively. The essential oils resulted in a lower LC50 of 159.263 ppm/mL, and LC90 of 320.930 ppm/mL within 24 h. In 48 h, the LC50 was 52.070 ppm/mL and the LC90 was 195.123 ppm/mL for C. quinquefasciatus. In the essential oil treatment of P. xylostella, the lower LC50 was 165.900 ppm/mL, and the LC90 was 343.840 ppm/mL 24 h after the treatment. At 48 h post-treatment, the LC50 decreased to 62.965 ppm/mL, and the LC90 decreased to 236.795 ppm/mL in P. xylostella. The study investigated the impact of essential oils on insect enzymes 24 h after treatment. The study revealed significant changes in the levels of insect enzymes, including a decrease in acetylcholinesterase enzymes and an increase in glutathione S-transferase compared to the control group. Essential oils had minimal effects, resulting in mortality rates of 30.66% and 46% at 24 and 48 h after treatment on Artemia salina. After 48 h, minimal toxic effects of essential oils were observed on E. eugeniae, with a mortality rate of 11.33%. The GC-MS analysis of A. nilotica seed-derived essential oils revealed ten major chemical constituents, including 6-hydroxymellein, phthalic acid, trichloroacetic acid, hexadecane, acetamide, heptacosane, eicosane, pentadecane, 1,3,4-eugenol, and chrodrimanin B. Among these constituents, Heptacosane is the major chemical component, and this molecule has a high potential for involvement in insecticidal activity.


Assuntos
Acacia , Inseticidas , Simulação de Acoplamento Molecular , Óleos Voláteis , Animais , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Acacia/química , Inseticidas/química , Inseticidas/toxicidade , Culex/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas , Mariposas/efeitos dos fármacos , Sementes/química
3.
Front Physiol ; 15: 1357411, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38496298

RESUMO

Chemical insecticides are effective at controlling mosquito populations, but their excessive use can pollute the environment and harm non-target organisms. Mosquitoes can also develop resistance to these chemicals over time, which makes long-term mosquito control efforts challenging. In this study, we assessed the phytochemical, biochemical, and insecticidal properties of the chemical constituents of cajeput oil. Results show that Melaleuca cajuputi essential oil may exhibit mosquito larvicidal properties against Anopheles stephensi larvae (second-fourth instar) at 24 h post-treatment. At 24 h post-exposure, the essential oil resulted in a significant decrease in detoxifying enzymes. All of these findings indicate that cajeput oil infects An. stephensi larvae directly affect the immune system, leading to decreased immune function. Cajeput oil significantly affects the second, third, and fourth instar larvae of An. stephensi, according to the bioassay results. Cajeput oil does not induce toxicity in non-target Eudrilus eugeniae earthworm species, as indicated by a histological study of earthworms. Phytochemical screening and GC-MS analysis of the essential oil revealed the presence of several major phytochemicals that contribute to mosquito larvicidal activity. The importance of cajeput oil as an effective candidate for biological control of the malarial vector An. stephensi is supported by this study.

4.
J Basic Microbiol ; 64(5): e2300744, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38466146

RESUMO

Tenebrio molitor L., also known as the mealworm, is a polyphagous insect pest that infests various stored grains worldwide. Both the adult and larval stages can cause significant damage to stored grains. The present study focused on isolating entomopathogenic fungi from an infected larval cadaver under environmental conditions. Fungal pathogenicity was tested on T. molitor larvae and pupae for 12 days. Entomopathogenic fungi were identified using biotechnological methods based on their morphology and the sequence of their nuclear ribosomal internal transcribed spacer (ITS). The results of the insecticidal activity indicate that the virulence of fungi varies between the larval and pupal stages. In comparison to the larval stage, the pupal stage is highly susceptible to Metarhizium rileyi, exhibiting 100% mortality rates after 12 days (lethal concentration 50 [LC50] = 7.8 × 106 and lethal concentration 90 (LC90) = 2.1 × 1013 conidia/mL), whereas larvae showed 92% mortality rates at 12 days posttreatment (LC50 = 1.0 × 106 and LC90 = 3.0 × 109 conidia/mL). The enzymatic analyses revealed a significant increase in the levels of the insect enzymes superoxide dismutase (4.76-10.5 mg-1) and glutathione S-transferase (0.46-6.53 mg-1) 3 days after exposure to M. rileyi conidia (1.5 × 105 conidia/mL) compared to the control group. The findings clearly show that M. rileyi is an environmentally friendly and effective microbial agent for controlling the larvae and pupae of T. molitor.


Assuntos
Larva , Metarhizium , Controle Biológico de Vetores , Pupa , Tenebrio , Animais , Tenebrio/microbiologia , Metarhizium/patogenicidade , Metarhizium/crescimento & desenvolvimento , Larva/microbiologia , Pupa/microbiologia , Virulência , Superóxido Dismutase/metabolismo , Glutationa Transferase/metabolismo
5.
Front Microbiol ; 15: 1336334, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38419636

RESUMO

In this study, we conducted tests on the isolation, identification, characterization, and extraction of chemical molecules from Beauveria bassiana against Tuta absoluta larvae. The enzyme responses of T. absoluta to the crude extract were examined 24 h after treatment, and the number of dead larvae was calculated 24 and 48 h after treatment. Molecular docking studies were conducted to assess the interaction of important molecules with the acetylcholinesterase enzyme. The larvicidal activity of crude chemicals from fungi was high 24 h after treatment, with LC50 and LC90 values of 25.937 and 33.559 µg/mL, respectively. For a period of 48 h, the LC50 and LC90 values were 52.254 and 60.450 µg/mL, respectively. The levels of acetylcholinesterase, α-carboxylesterase, and ß-carboxylesterase enzymes were lower in the treatment group after 24 h compared to the control group. The GC-MS test revealed that the crude extract consisted mainly of 9,10-octadecadienoic acid, which was the primary compound. Docking results indicated that 9,10-octadecadienoic acid showed a strong interaction with acetylcholinesterase (AChE). Our findings suggest that the chemical molecule 9,10-octadecadienoic acid derived from the entomopathogenic fungus B. bassiana is more toxic to T. absoluta larvae. We plan to conduct studies to test its effectiveness in semi-field conditions and to evaluate its stability in field conditions. We believe that this 9,10-octadecadienoic acid molecule could be used to control T. absoluta larvae in the near future without causing environmental pollution.

6.
Heliyon ; 10(1): e23406, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38187317

RESUMO

Pesticides play a pivotal role in agriculture for the effective production of various crops. The indiscriminate use of pesticides results in the significant bioaccumulation of pesticide residues in vegetables. This situation is beyond the control of consumers and poses a serious health issue for human beings. Occupational exposure to pesticides may occur for farmers, agricultural workers, and industrial producers of pesticides. This occupational exposure primarily causes food and water contamination that gets into humans and environmental pollution. Depending on the toxicity of pesticides, the causes and effects differ in the environment and in human health. The number of criteria used and the method of implementation employed to assess the effect of pesticides on humans and the environment have been increasing, as they may provide characterization of pesticides that are already on the market as well as those that are on the way. The biological control of pests has been increasing nowadays to combat all these effects caused by synthetic pesticides. Myco-biocontrol has received great attention in research because it has no negative impact on humans, the environment, or non-target species. Entomopathogenic fungi are microbes that have the ability to kill insect pests. Fungi also make enzymes like the lytic enzymes, esterase, oxidoreductase, and cytochrome P450, which react with chemical residues in the field and break them down into nontoxic substances. In this review, the authors looked at how entomopathogenic fungi break down insecticides in the environment and how their enzymes break down insecticides on farms.

7.
Front Cell Infect Microbiol ; 13: 1254475, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38149005

RESUMO

Background: 'The fall armyworm, Spodoptera frugiperda', represents a significant threat to maize production, a major staple crop in Asian countries. Methods: In pursuit of more effective control of this insect pest, our study assessed the physiological and biochemical effects of the entomopathogenic fungus Metarhizium anisopliae against the larvae of S. frugiperda. Results: Results revealed that, following nine days of treatment, a high concentration of conidia (1.5x107 conidia/mL-1) was toxic to all stages of larvae (second to fifth instar), resulting in 97% mortality of the second instar, 89% mortality of the third instar, 77% mortality of the fourth instar, and 72% mortality of fifth instar. All larval instars were found to have dose-dependent mortality effects. Treated S. frugiperda larvae further displayed significant physiological, morphological, and behavioral changes. Here, treated larvae displayed significantly lower levels of acetylcholinesterase, α-carboxylesterase, and ß-carboxylesterase enzyme activity when compared to control groups. Treated larvae underwent an outward morphological change as the result of a decrease in the exterior cuticle of the anal papillae and a demelanization of the interior cuticle. Treated larvae also exhibited abnormal feeding behaviors as a consequence of the negative impact of conidia treatment on the neuromuscular system. Investigation into the effect of M. anisopliae on the non-target organism, the earthworm Eudrilus eugeniae, revealed that M. anisopliae conidia did not produce significant pathogenicity following three days of treatment. Furthermore, histological analysis revealed no significant effect of the entomopathogenic fungi on the gut tissue of the non-target organism. Conclusion: This study highlights the potential of M. anisopliae in the control of S. frugiperda.


Assuntos
Inseticidas , Animais , Inseticidas/farmacologia , Spodoptera , Acetilcolinesterase/farmacologia , Larva/microbiologia , Fungos , Esporos Fúngicos
8.
Biotechnol Appl Biochem ; 70(3): 1346-1356, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36724497

RESUMO

In the present study, the green synthesis of silver nanoparticles (AgNPs) using ethanol extract of Cymodocea serrulata and biological activity were investigated by UV-visible spectrophotometer, Fourier-transform infrared spectroscopy (FTIR), x-ray powder diffraction (XRD), and scanning electron microscopy. The results show that nanoparticles synthesized were confirmed by color change from green to dark brown. The XRD analysis confirmed that the AgNPs were crystalline and found that their UV maximum specific absorbance was between 200 and 400 nm, and their field emission scanning electron microscopy size was between 60 and 69 nm. FTIR studies identified different functional groups involved in the potential capping of AgNPs. The antidiabetic activity of the AgNPs was tested by the inhibition of carbohydrate digestive enzymes (a-glucosidase and amylase). In addition, it has exhibited potential anticancer activity against breast cancer cells (MDF7). Hence, the present result warrants ecofriendly and efficient method in the synthesis of AgNPs, which can act as an alternative biomaterial for biomedical applications.


Assuntos
Antioxidantes , Nanopartículas Metálicas , Antibacterianos/farmacologia , Antioxidantes/farmacologia , Antioxidantes/química , Nanopartículas Metálicas/química , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Prata/farmacologia , Prata/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X , Neoplasias da Mama , Antineoplásicos/química , Antineoplásicos/farmacocinética
9.
Sci Rep ; 12(1): 16775, 2022 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-36202839

RESUMO

Insect pests of agricultural crops have establish immunological tolerance against fungal infection caused by pathogens via different humoral and cellular processes. Fungal infection can be prevented by insect antioxidant and detoxifying enzymes, but there is no clear understanding of how they physiologically and biochemically interact. Our study aims to examine the antioxidant and detoxifying enzyme defense systems of the pest insect Spodoptera litura in response to infection by Metarhizium flavoviride. At 48 h following exposure to M. flavoviride, antioxidant enzyme levels were modified, and phenoloxidase and total hemocyte count were decreased significantly. The amount of detoxifying enzymes increased significantly. M. flavoviride appears to directly affect the S. litura immune system and results in decreased immunity. In a bioassay, M. flavoviride was found to be harmful to S. litura larvae in their third and fourth instar stage. M. flavoviride may be an effective tool in the control of S. litura larvae. Such entomopathogenic fungi represent cheaper, pollution free, target specific, promising alternatives to synthetic chemical tools in the for control insect pests.


Assuntos
Metarhizium , Mariposas , Animais , Antioxidantes/farmacologia , Larva , Monofenol Mono-Oxigenase , Spodoptera , Esporos Fúngicos , Virulência
10.
J Fungi (Basel) ; 8(3)2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-35330302

RESUMO

Insecticides can cause significant harm to both terrestrial and aquatic environments. The new insecticides derived from microbial sources are a good option with no environmental consequences. Metarhizium anisopliae (mycelia) ethyl acetate extracts were tested on larvae, pupae, and adult of Anopheles stephensi (Liston, 1901), Aedes aegypti (Meigen, 1818), and Culex quinquefasciatus (Say, 1823), as well as non-target species Eudrilus eugeniae (Kinberg, 1867) and Artemia nauplii (Linnaeus, 1758) at 24 h post treatment under laboratory condition. In bioassays, Metarhizium anisopliae extracts had remarkable toxicity on all mosquito species with LC50 values, 29.631 in Ae. aegypti, 32.578 in An. stephensi and 48.003 in Cx. quinquefasciatus disease-causing mosquitoes, in A. nauplii shows (5.33-18.33 %) mortality were produced by the M. anisopliae derived crude extract. The LC50 and LC90 values were, 620.481; 6893.990 µg/mL. No behavioral changes were observed. A low lethal effect was observed in E. eugeniae treated with the fungi metabolites shows a 14.0 % mortality. The earthworm E. eugeniae mid-gut histology revealed that M. anisopliae extracts had no more harmful effects on the epidermis, circular muscle, setae, mitochondrion, and intestinal lumen tissues than chemical pesticides. By Liquid chromatography mass spectrometry (LC-MS) analysis, camphor (25.4 %), caprolactam (20.68 %), and monobutyl phthalate (19.0 %) were identified as significant components of M. anisopliae metabolites. Fourier transform infrared (FT-IR) spectral investigations revealed the presence of carboxylic acid, amides, and phenol groups, all of which could be involved in mosquito toxicity. The M. anisopliae derived chemical constituents are effective on targeted pests, pollution-free, target-specific, and are an alternative chemical insecticide.

11.
Insects ; 12(11)2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34821816

RESUMO

Fall armyworm Spodoptera frugiperda is a major pest of corn, rice, and sorghum among other crops usually controlled using synthetic or biological insecticides. Currently, the new invention of nanotechnology is taking root in the agricultural industry as an alternative source of pest management that is target-specific, safe, and efficient. This study sought to determine the efficacy of commercial Zinc Oxide (ZnO) nanoparticles (NPs) towards S. frugiperda under laboratory conditions. ZnO NPs were diluted into different concentrations (100-500 ppm), where the baby corn used to feed the S. frugiperda larvae was dipped. The development of the insect feeding on food dipped in ZnO solution was significantly (p < 0.05) affected, and the number of days that the insect took to complete its life cycle had a significant difference compared to the control. There was a significant difference in the adults' emergence in all the concentrations of ZnO NPs compared to the control, with over 90% of the eggs successfully going through the life cycle until adult emergence. Additionally, several body malformations were observed throughout the lifecycle of the insect. Also, the fecundity of the females was greatly affected. The findings of this study suggest the possibility of exploitation of ZnO nanoparticles not only to manage S. frugiperda but to significantly reduce their population in the ecosystem through body deformations, reduced fecundity, reduced oviposition, and hatchability of eggs. It will be a valuable tool in integrated pest management regimens.

12.
Artigo em Inglês | MEDLINE | ID: mdl-34639837

RESUMO

Currently, medical and stored grain pests are major concerns of public health and economies worldwide. The synthetic pesticides cause several side effects to human and non-target organisms. Copper nanoparticles (CuNPs) were synthesized from an aqueous extract of Metarhizium robertsii and screened for insecticidal activity against Anopheles stephensi, Aedes aegypti, Culex quinquefasciatus, Tenebrio molitor and other non-target organisms such as Artemia salina, Artemia nauplii, Eudrilus eugeniae and Eudrilus andrei. The synthesized copper nano-particles were characterized using, UV-vis spectrophotometer, Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Energy Dispersive X-Ray analysis (EDaX), High Resolution Scanning Electron Microscope (HR-SEM) and Atomic Force Microscope (AFM) analysis. Insects were exposed to 25 µg/mL concentration produced significant mortality against larvae of A. stephensi, A. aegypti, C. quinquefasciatus and T. molitor. The lower toxicity was observed on non-target organisms. Results showed that, M. robertsii mediated synthesized CuNPs is highly toxic to targeted pests while they had lower toxicity were observed on non-target organisms.


Assuntos
Aedes , Culex , Inseticidas , Nanopartículas Metálicas , Praguicidas , Animais , Cobre/toxicidade , Humanos , Inseticidas/toxicidade , Larva , Nanopartículas Metálicas/toxicidade , Metarhizium , Extratos Vegetais , Folhas de Planta , Prata
13.
PLoS One ; 15(5): e0232172, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32365106

RESUMO

BACKGROUND: The fungal toxin acts as effective, low-cost chemical substances for pest control worldwide and also an alternative to synthetic insecticides. This study assessed the larvicidal potential of Metarhizium anisopliae fungi derived metabolites against Aedes aegypti, Anopheles stephensi, Culex quinquefasciatus and non-targeted organisms at 24hr post treatment. METHOD: Isolation of entomopathogenic fungi M. anisopliae from natural traps confirmed by using 18s rDNA biotechnological tools. Crude extracts from M. anisopliae solvent extraction and their secondary metabolites were bio-assayed following WHO standard procedures against Ae. aegypti, An. stephensi and Cx. quinquefasciatus, Artemia nauplii, Eudrilus eugeniae, and Solanum lycopersicum after 24 hr exposure. Histopathological analysis of E. eugeniae treated with fungi metabolites toxicity compared to those treated with Monocrotophos after 24hrpost-treatment. M. anisopliae metabolites were characterized using GC-MS and FT-IR analysis. RESULTS: The larvicidal activity was recorded in highest concentration of 75µg/ml, with 85%, 97% and 89% mortality in Ae. aegypti, An. stephensi and Cx. quinquefasciatus respectively. M. anisopliae metabolites produced LC50 values in Ae. aegypti, 59.83µg/ml, in An. stephensi, 50.16µg/ml and in Cx. quinquefasciatus, 51.15µg/ml respectively. M. anisopliae metabolites produced lower toxic effects on A. nauplii, LC50 values were, 54.96µg/ml respectively. Bio-indicator toxicity results show 18% and 58% mortality was recorded in E. eugeniae and A. nauplii and also there is no phytotoxicity that was observed on S. lycopersicum L. under semi-field condition. E. eugeniae histopathological studies shows fungal metabolites showed lower sub-lethal effects compared to synthetic chemical pesticide at 24hrs of the treatment. The GC-MS and FT-IR analysis identified five major components of active ingredients. CONCLUSION: Findings of this study indicate that, M. anisopliae ethyl acetate derived secondary metabolites are effective against larvae of Ae. aegypti, An. stephensi and Cx. quinquefasciatus mosquito species, lower toxicity effects were observed on non-target organisms such as, Artemia nauplii, Eudrilus eugeniae as well as, no toxicity effect were observed on Solanum lycopersicum. Further research should be conducted in laboratory for separation of single pure molecule and be tested semifield conditions.


Assuntos
Aedes/efeitos dos fármacos , Anopheles/efeitos dos fármacos , Produtos Biológicos/farmacologia , Culex/efeitos dos fármacos , Metarhizium/química , Animais , Produtos Biológicos/química , DNA Fúngico/genética , DNA Ribossômico/genética , Cromatografia Gasosa-Espectrometria de Massas , Controle de Insetos , Larva/efeitos dos fármacos , Metarhizium/genética , Metarhizium/isolamento & purificação , Monocrotofós/farmacologia , RNA Ribossômico 18S/genética , Metabolismo Secundário , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Nat Prod Res ; 34(18): 2626-2629, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30623679

RESUMO

In this study Eucalyptus globulus essential oil was tested on major mosquito species and toxicity was compared with temephos. Mortality was calculated after 24 h and 48 h post treatment. In 24 h treatment essential oil show strong larvicidal activity with LC50 and LC90 values were 30.198ppm, 103.389ppm for Anopheles stephensi, 13.578ppm, 106.755ppm for Aedes aegypti; and, 7.469ppm, 32.454ppm for Culex quinquefasciatus and 48 h post treatment LC50 and LC90 values were, 12.576, 49.380ppm for Anopheles stephensi, 7.926, 34.470ppm for Aedes aegypti and 4.408, 21.048ppm for Culex quinquefasciatus. Chemical composition of essential oil using GC-MS and FT-IR analysis shows the presence of 1,8-cineol, (71.7%); α-pinene, (9.14%) as a major compounds. Our findings suggest that essential oil from Eucalyptus globulus leaves can be used for control of mosquito larvae.


Assuntos
Aedes/efeitos dos fármacos , Eucalyptus/química , Óleos Voláteis/farmacologia , Temefós/toxicidade , Animais , Anopheles , Monoterpenos Bicíclicos/análise , Culex , Inseticidas/química , Larva/efeitos dos fármacos , Óleos Voláteis/química , Extratos Vegetais/química , Espectroscopia de Infravermelho com Transformada de Fourier
15.
Artigo em Inglês | MEDLINE | ID: mdl-29510502

RESUMO

Microbial-based pest control is an attractive alternative to chemical insecticides. The present study sought to evaluate the toxicity of the entomopathogenic fungus Beauveria bassiana-28 ethyl acetate extracts on different larval stages and pupae of Culex quinquefasciatus mosquitoes. B. bassiana-28 ethyl acetate mycelial extracts produced mosquitocidal activity against larvae and pupae which was comparable to that of the commercial insecticide B. bassiana-22 extract. The LC50 (lethal concentration that kills 50% of the exposed larvae) values of B. bassiana-28 extracts for 1st to 4th instar larvae and pupae were 11.538, 6.953, 5.841, 3.581 and 9.041 mg/L respectively. Our results show that B. bassiana-28 ethyl acetate mycelial extract has strong insecticidal activity against larval and pupal stages of Cx. quinquefasciatus. Fourier transform infrared spectrum study of B. bassiana-28 extract shows peaks at 3226.91; 2927.94; 1593.13; 1404.18; 1224.18; 1247.94; 1078.21; 1018.41; 229.69; and 871.82 cm-1. Major spectral peaks were observed at 3226.91 cm-1, assigned to N-H stretching, 2927.94 cm-1 assigned to C-H bonding and 1595.13 cm-1 assigned to C-O stretching. Gas Chromatography-Mass Spectrometry studies of B. bassiana-28 ethyl acetate crude extract showed presence of six major compounds viz. N-hexadecanoic acids (13.6040%); Z,Z-9,12 octadecadienic acid (33.74%); 9-eicosyne (10.832%); heptacosane (5.148%); tetrateracontane (5.801%); and 7 hexyleicosane (5.723%). Histology of mosquito midgut tissue shows tissue lysis as a result of B.bassiana-28 extract exposure. The study shows that bioactive molecules obtained from B. bassiana-28 mycelial extract has insecticidal properties and can be used as alternative for mosquito control.


Assuntos
Beauveria/química , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Micélio/química , Extratos Vegetais/toxicidade , Pupa/efeitos dos fármacos , Animais , Culex/efeitos dos fármacos , Índia , Inseticidas/química , Controle de Mosquitos/métodos , Extratos Vegetais/química
16.
Pathog Glob Health ; 112(1): 37-46, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29457957

RESUMO

Mosquito control using chemical insecticides is facing a major challenge due to development of insecticide resistance. Improving the efficiency of existing insecticides using synergistic secondary metabolites of biological origin is increasingly being researched. Herein, we evaluated the toxicity of Fusarium oxysporum extract alone and in binary combinations with temephos, on larvae and pupae of Anopheles stephensi, Aedes aegypti and Culex quinquefaciatus. F. oxysporum extract was characterized using TLC, FT-IR and GC-MS. After 24 h of exposure, the binary combination of temephos + F. oxysporum extract (1:1 ratio) was highly toxic to larvae of An. stephensi (LC50: 35.927 µg/ml), Ae. aegypti (LC50: 20.763 µg/ml) and Cx. quinquefasciatus, (LC50: 51.199 µg/ml). For pupae LC50 values were 38.668, 26.394, and 72.086 µg/ml, respectively. Histology studies of mosquitoes exposed to F. oxysporum extract showed vacuolation in epithelium, as well as in adipose, and muscle tissues of larval midgut. Overall, our results show that the synergistic combination of temephos and F. oxysporum extract is highly effective to control mosquito young instars.


Assuntos
Misturas Complexas/farmacologia , Sinergismo Farmacológico , Fusarium/química , Inseticidas/farmacologia , Mosquitos Vetores/efeitos dos fármacos , Temefós/farmacologia , Aedes , Animais , Anopheles , Cromatografia em Camada Fina , Misturas Complexas/química , Misturas Complexas/isolamento & purificação , Culex , Cromatografia Gasosa-Espectrometria de Massas , Histocitoquímica , Larva/efeitos dos fármacos , Pupa/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Análise de Sobrevida
17.
Artigo em Inglês | MEDLINE | ID: mdl-29473901

RESUMO

Botanical metabolites are increasingly realized as potential replacements to chemical insecticides. In the present study, Acacia nilotica seed essential oil and seed pod solvent extracts were tested for bioefficacy against three important types of mosquitoes. Mortality was recorded 24 h post-treatment, while smoke toxicity of adult mosquitoes was recorded at 10 min intervals for 40 min. Seed pod powder was extracted with different solvents and hydrodistilled seed oil chemical constituents were determined by using Gas chromatography mass spectroscopy (GC-MS) -. Larvicidal and adulticidal efficacy of seed hydrodistilled essential oil and solvent extracts were tested against larval and adult mosquitoes. The seed hydrodistilled oil provided strong larvicidal activity against Anopheles stephensi, (LC50 (lethal concentration that kills 50% of the exposed larvae) = 5.239, LC90 (lethal concentration that kills 90% of the exposed larvae) = 9.713 mg/L); Aedes aegypti, (LC50 = 3.174, LC90 = 11.739 mg/L); and Culex quinquefasciatus, (LC50 = 4.112, LC90 = 12.325 mg/L). Smoke toxicities were 82% in Cx. quinquefasciatus, 90% in Ae. aegypti, and 80% mortality in An. stephensi adults, whereas 100% mortality was recorded for commercial mosquito coil. The GC-MS profile of seed essential oil from A. nilotica showed the presence of hexadecane (18.440%) and heptacosane (15.914%), which are the main and active compounds, and which may be involved in insecticidal activity. Overall findings suggest that the seed oil showed strong mosquitocidal activity against mosquito vectors and therefore may provide an ecofriendly replacement to chemical insecticides.


Assuntos
Acacia/química , Aedes/efeitos dos fármacos , Anopheles/efeitos dos fármacos , Culex/efeitos dos fármacos , Mosquitos Vetores/efeitos dos fármacos , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Animais , Índia , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Extratos Vegetais/química , Sementes/química
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