Instar Larvae Of Aedes Aegypti Research Articles

Chemical composition and larvicidal activity of essential oils from Peganum harmala, Nepeta cataria and Phellodendron amurense against Aedes aegypti (Diptera: Culicidae)

Essential oils from aerial parts of the herbs Peganum harmala and Nepeta cataria, and leaves of the tree Phellodendron amurense were analyzed by GC-FID and GC-MS, and their larvicidal activities were assayed on the early fourth instar larvae of Aedes aegypti. The major constituents of the oils were limonene (14.5%) and thymol (11.5%) in P. harmala, thymol (46.5%), 4aα,7α,7aβ-nepetalactone (18.3%) and 4aα,7β,7aα-neptalactone (19.7%) in N. cataria, eugenol (14.5%) andγ-eudesmol (9.5%) in P. amurense.The oil of N. cataria had a strong larvicidal activity (LC50 < 50 µg/mL; LC90 < 86.8 µg/mL) on A. aegypti while the remaining oils showed a moderated killing effect. The larvicidal activity of N. cataria oil was associated to the contents of 1,8-cineol, camphor, 4aα,7α,7aβ-Nepetalactone, 4aα,7β,7aα-Nepetalactone and thymol. Our results indicate that the oil of N. catariadeserves to be used as a source of larvicidal agents against A. aegypti.

Utilization of Basil Leaf Extract as Anti-Mosquito Repellent: A Case Study of Total Mosquito Mortality (Aedes aegypti 3rd Instar)

This study aims to determine the most effective concentration of extract that kills the larvae in the third instar Aedes aegypti, knowing the value of LC50 and LC90 anthen knowing the value of LT50 and LT90 of forest basil leaf extract (Ocimum sanctum). Research is using a completely randomized design with factorial, and the first factor is forest basil leaf extract with 5 level concentrations, there are 0.3%, 0.6%, 0.9%, 1.2%, 1.5%, and 0% as control, whereas the second factor is observation period that began after the death of the larvae. Observations were made up to 4320 minutes. The results showed the influence of forest basil leaf extract against third instar larvae mortality of Aedes aegypti, and the most effective concentration of basil leaf extract to kill the larvae was 1.5%. LC50 values of this study was 0.97%, and for the LC90value was 1.42%. Value of LT50and LT90 of this study is 5,71 hours or 342,31 and 17,02 hours or 1021.22 minutes. The conclusion of this study is basil leaf extract forest affect mortality third instar larvae of Aedes aegypti, and the most effective concentration of extract was 1.5%.

Effectivity of Bacterial Suspension Bacillus thuringiensis Var Israelensis in Killing Aedes aegypti L. Mosquito Larvae

Objective: Dengue hemorrhagic fever is a disease transmitted by the mosquito Aedes aegypti. Prevention of transmission of this disease one of which is the chemical control with temefos, but the use of sustainable temefos can cause insect resistance and environmental damage. Therefore we need an effective and safe alternative to larvicide, the suspension of Bacillus thuringiensis var israelensis.&#x0D; Methods: This study used a type of true experimental research design with posttest only control group design. Samples used in this study are the third instar larvae of Aedes aegypti. Concentrations used in this study were a 0.01%; Of 0.02%; Of 0.03%; 0:04% and 0.05% by the number of 25 larvae per treatment and 3 times replication.&#x0D; Results: Based on the Kruskal Walls obtained a value of 0.009&gt; 0.05 means there is a stock mortality of larvae using a suspension of the bacterium Bacillus thuringiensis, temefos and distilled. Test Mann Whitney showed that among the positive control (temefos a 0.01%) and negative control (distilled water) there are differences in the number of larvae mortality significantly, the positive control treatment with no significant difference, and between negative control and treatments armpits there are differences in the number of deaths larvae significant. The LC50 value obtained was 0.010% and the LT50 value obtained was 2,683 hours.&#x0D; Conclusions: The suspension of bacteria Bacillus thuringiensis is effective in killing the larvae of Aedes aegypti with LC50 values of 0.0105 and LT50 values on the clock to 2.683.&#x0D; Bangladesh Journal of Medical Science Vol.18(4) 2019 p.706-710

Toxicity of the aqueous leaf and Stem-bark extracts of &lt;em&gt;Annona muricata &lt;/em&gt;to the 4&lt;sup&gt;th&lt;/sup&gt; instar larvae of &lt;em&gt;Aedes aegypti&lt;/em&gt;

The crude aqueous extracts were tested against the fourth instar larvae of Aedes aegypti (Diptera: Culicidae) at five concentrations of the technical material ranging from 12.5-200 µg/ml, including control. The bioassays were carried out in the laboratory at temperature of 29◦C ± 2 and 29.5 ± 5% relative humidity. Four replicates of each concentration of the respective toxicants in a Completely Randomised Design (CRD) were introduced with ten fourth instar larvae of Ae. Aegypti. Mortality resulting from eclosion inhibition was monitored at 3-hours interval for a period of 3, 6, 9, 12- and 24-hours post treatment. Data collected were analyzed using log-probit regression and analysis of variance. Results showed that mortality increased with increase in time and concentration and these were significantly different (P<0.05). Results indicated 65% and 87.1% mortality at the highest concentration (200 µg/ml) of the leaf and stem-bark aqueous extract respectively while the least concentration (12.5 µg/ml) resulted in 19.4% and 38.7% respectively. The LC50 values were 92.5 µg/ml and 26.5 µg/ml for the leaf and stem-bark aqueous extract respectively while the LT50 values were 29.7hr and 53.9hr respectively for the leaf and the stem-bark aqueous extract. The study suggests that Annona muricata leaf and stem-bark aqueous extract has shown promise as biopesticide for Ae. Aegypti larvae control. However, the stem-bark was found to be more effective compared to the leaf aqueous extract.

Seasonal variation in the chemical composition and larvicidal activity against Aedes aegypti of essential oils from Vitex gardneriana Schauer

The seasonal variation in essential oils from leaves of Vitex gardneriana Schauer was studied. Analysis of the chemical composition showed the presence of 3 monoterpenes, 2 non-oxygenated (α-pinene and β-pinene) and 1 oxygenated (eucalyptol), and 24 sesquiterpenes, 21 non-oxygenated and 3 oxygenated. The main compound, 6.9-guaiadiene, presented the highest concentrations in October (30.15%), January (28.86%) and February (22.73%); cis-calamenene had the highest concentrations in December (35.62%), April (34.92%), November (34.63%) and March (33.57%); and caryophyllene oxide possessed the highest concentrations in September (16.68%), January (15.06%) and August (14.39%). Additionally, essential oils extracted in January (LC50 78.3 μg/mL), March (LC50 44.1 μg/mL), April (LC50 47.9 μg/mL), May (LC50 28.0 μg/mL), July (LC50 43.5 μg/mL), August (LC50 62.0 μg/mL) and December (LC50 84.3 μg/mL) exhibited significant larvicidal activity against third instar larvae of Aedes aegypti.

In-vitro study on the larvicidal activity of Manihot glaziovii peel extract against Aedes aegypti larvae

Use of chemical method to control Aedes aegypti population in the Dengue endemic areas caused the emergence of a resistant strain of this species to insecticide compounds, including temephos. Exploration of the alternative compounds that have larvicidal effects is needed, such as natural products derivate from plants. The current study was designed to evaluate the effective dosage of methanolic extract of Manihot glaziovii peel against the third instar larvae of Aedes aegypti. Bioassay test was performed based on the WHO procedure to occupy the 24 hours exposure of five levels dosages of Manihot glaziovii peel extract, namely 1,800, 2,400, 3,000, 3,600 and 4,200 ppm respectively. As many as 25 of healthy Aedes aegypti larvae were subjected into each group, five-time replicated and compared with tap water control group. The mortality rate of Aedes aegypti larvae has increased due to the increase in treatment groups dosages, ranged from 44–97.6%. It is significantly different in larvae mortality rate between different treatment groups. There was no observation of killed larvae in the control group. LD50 and LD90 of methanolic extract of Manihot glaziovii peel were measured 2,027 ppm and 3,772 ppm, respectively. This result suggests the possible use as an ecofriendly larvicide against Aedes aegypti larvae. Further investigation is needed to obtain secondary metabolites of this plant.

Activity of the compounds isolated from &lt;i&gt;Blighia sapida&lt;/i&gt; (sapindaceae) stem bark against &lt;i&gt;Aedes aegypti&lt;/i&gt; larvae

Blighia sapida (Sapindaceae) is commonly known as Ackee and in the South West Nigeria it is called Isin. The wood is resistant to termites and the pounded fruit and the stem bark is used as fish poison. The methanol extract of the stem bark reported to be active against the fourth instar larvae of Aedes aegypti was suspended in water and partitioned into n-hexane, dichloromethane and ethyl acetate. The most active n-hexane fraction with activity that was statistically insignificant to that of the methanolic extract gave LC50 , LC90 values of 1.81 ± 0.02, 3.17 ± 0.02 mg/mL at 24 h and 1.65 ± 0.05, 2.82 ± 0.35 mg/mL at 48 h. Endosulphan the positive control, had LC50 , LC90 values of 0.93 ± 0.06, 1.61 ± 0.12 mg/mL at 24 h and 0.90 ± 0.09, 1.44 ± 0.11 mg/mL at 48 h. The n-hexane fraction was subjected to chromatographic separations that led to the isolation of friedelin and α-amyrin. Friedelin and α-amyrin gave LC50 LC90 0.07 ± 0.01, 0.13 ± 0.01 mg/mL and 0.05 ± 0.00, 0.08 ± 0.01 mg/mL respectively at 24 h and at 48 h there was 100% mortality. The activity of both compounds was statistically higher than that of Endosulphan.Keywords: Blighia sapida, extract, chromatography, friedelin, α-amyrin, Aedes aegypti

Antimicrobial and larvicidal activity of eco-friendly silver nanoparticles synthesized from endophytic fungi Phomopsis liquidambaris

Abstract In the quest for developing a biological-based nanomaterial for therapeutic applications, here we report a novel benign method of silver nanoparticles synthesized using the endophytic fungi Phomopsis liquidambaris strain SA1 (SAAgNPs). A viable method was developed to generate silver nanoparticles by reacting with silver nitrate and an extracellular filtrate of P.liquidambaris as a reducing and stabilizing agent. After formation of brown color, synthesized SAAgNPs was measured for its Surface Plasmon Resonance (SPR) which produces an intense absorption spectrum at 430 nm. Fourier Transform Infrared Spectroscopy (FTIR) revealed the functional group moieties involved as a capping and reducing agent in SAAgNPs synthesis. Stable, spherical and polydispersed nanoparticles with an average size of 18.7 nm were affirmed by Transmission Electron Microscope (TEM). X-ray Diffraction study showed the diffraction peaks corresponds to (111), (200), (220) and (311) planes resembling cubic crystalline in nature. Energy dispersive analysis (EDAX) identifies the silver as a major compositional element. Moreover, SAAgNPs performed better growth inhibitory activity against the tested pathogens. Further, SAAgNPs arrest the growth of IInd and IVth instar larvae of Aedes aegypti and Culex quinquefasciatus in a dose-dependent method. Finally, SAAgNPs exhibited very low hemolytic activity; suggesting the biocompatibility and feasibility of SAAgNPs as a therapeutic agent. Thus, the study bestowed the isolation of endophytic fungi Phomopsis liquidambaris and its mediated synthesis of silver nanoparticles. Further, SAAgNPs proved its efficacy as an effective antimicrobial and mosquitocidal agent.

Hypericum japonicum: a Double-Headed Sword to Combat Vector Control and Cancer.

Mosquito control with naturally derived herbal insecticides has gained much momentum, with the increased insecticide resistance of vectors and the multiple infectious diseases spread by them. Yet, recent studies also suggest that mosquitoes could probably transmit some cancerous cells or cancer-causing viruses from one individual to another between their blood meals. The current research thus focused on the screening and characterization of novel plants with both mosquitocidal and anticancerous properties. Accordingly, different solvent extracts of Hypericum japonicum, a key plant in Chinese medicine, were screened for its larvicidal efficacy using the fourth instar larvae of Aedes aegypti (major vector of Dengue and chikungunya). Methanolic extracts of the plant showed effective larvicidal property with LC50 7.37ppm and LC9011.59ppm values. The anticancerous property of the plant extract was also evaluated by in vitro cytotoxicity assay against Daltons Lymphoma Ascites (DLA) cells. The results indicated that H. japonicum plant extracts at very low concentrations of LC500.95ppm and LC901.85ppm were potent cytotoxic agents. To the best of our knowledge, this is the first and the foremost report of Hypericum japonicum as a potent mosquitocidal and anticancerous agent. Identification and characterization of such plant-derived bioactive plants thus could serve as a double-headed sword against the spread of infectious diseases and cancer.

Effectiveness of Beauveria bassiana Powder as Larvacide to Aedes aegypti Linnaeus, 1762 Larvae

Study of effectiveness of Beauveria bassiana Powder as Larvacide to Aedes aegypti larvae was conducted on September 2016 to May 2017 in Ecologi and Systematics Animal Laboratory, Faculty of Mathematics and Natural Sciences, University of Mulawarman. This study aimed to determine the effect of Beauveria bassiana powder with use flour rice media on differents concentration as larvacide to mortality of larvae Aedes aegypti. Stages of study include arranged experimental design (Completely Randomized Design) with concentration of 0%, 0.125%, 0.25%. 0.5% and 0.75%, taking sample, rearing third instar larvae of Aedes aegypti and application Beauveria bassiana powder in 48 hours observation. The mortality value of larvae willbe presented on percentage tabel and graph. The result showed, this product is capable of killing larvae for 48 hours with the percentage mortality 0%, 10%, 28%, 70% and 80% in each concentration. Mortality of larvae is influenced by concentration and period of exposure. Increased of product concentration that given and period of exposure can effected increased of mortality percentage.&#x0D; Keywords: mortality, Beauveria bassiana powder, Aedes aegypti larvae

Screening of phytochemical and pharmacological activities of Syzygium caryophyllatum (L.) Alston

BackgroundThe systematic screening of plant species with the purpose of discovering new bioactive compounds is prerequisite for any bioprospecting study. Therefore the present study was carried out to assess the phytochemical content and the evaluation of in vitro antioxidant, antibacterial, larvicidal and antidiabetic activities of the methanol extracts of S.caryophyllatum bark, leaves, fruit pulp and seeds.MethodsThe quantitative estimation of total phenol, flavonoid and tannin content of the extracts of S. caryophyllatum bark, leaf, fruit pulp and seeds were analyzed by using standard methods. The present study also conducted to screen antioxidant (DPPH, ABTS assays), antimicrobial, antidiabetic (in vitro α-amylase and α-glucosidase inhibitory assays) and larvicidal (against fourth instars larvae of Aedes aegypti and Culex quinquefasciatus) activities of methanol extract of S. caryophyllatum.ResultsThe results of quantitative phytochemical analysis revealed the presence of maximum amount of phytoconstituents such as phenol, flavonoids and tannins in the leaf, bark and seed extract when compared to fruit pulp extracts. Free radical scavenging activity indicated that methanol bark, leaves, fruit and seeds extracts has significant free radical scavenging ability on DPPH with percentage inhibition of 88.15%, 81.31%, 75.24% and 83.36% respectively. The in vitro α-amylase and α-glucosidase inhibitory studies of the methanol crude extracts of four different plant parts of S. caryophyllatum (Bark, leaf fruit pulp and seed) showed good inhibitory activities in concentration dependent manner. The maximum percentage inhibitory activity of 78.03% was showed at concentration of 500 μg/ml seed extracts followed by bark (78.03%), leaf (69.4%) and fruit pulp (56.9%) at the same concentration. While the percentage inhibitory activity of four extracts also showed potent inhibition of α-glucosidase; maximum inhibition exhibited at the concentration of 100 μg/ml by bark extract (80.9%) compared with other extracts, leaf (78.2%), seed (77.59%) and fruit pulp (63.35%). The leaf essential oil and four extracts showed significant mortality against fourth instars larvae of Ae. aegypti and Cx. quinquefasciatus respectively.ConclusionThus the present study suggests that S.caryophyllatum plant parts can be used as natural antioxidant source to prevent diseases associated with free radicals. Also, this plant can be a good source for further purification studies for isolation and characterization of compounds related to these antioxidants, antidiabetic and antibacterial activities.

Aristololactam derivatives from the fruits of Aristolochia contorta Bunge

Three new aristololactam derivatives, aristololactam W–Y (1–3), and three known compounds (4–6) were isolated from the fruits of Aristolochia contorta Bunge. Compounds 1 and 2 represent the first example of an N-CH2OCH3 aristololactam derivative from natural products. Their structures were elucidated by 1D/2D NMR and HRESIMS spectra. All of the isolated compounds were evaluated for their insecticidal activity against 4th instar larvae of Aedes aegypti. Compound 4 displayed insecticidal activity with LC50 value of 3.54 μg/mL.

INSECTICIDAL, ANTIBACTERIAL, AND ANTIRADICAL ACTIVITY OF NICOTIANA PLUMBAGINIFOLIA VIV. (SOLANACEAE)

Objectives: Nicotiana plumbaginifolia Viv. belongs to the family Solanaceae. The present study was carried out to determine insecticidal, antibacterial, and antiradical activity of aerial parts of N. plumbaginifolia.Methods: Extraction was carried out by maceration process using methanol. Insecticidal activity was assessed, in terms of larvicidal effect, against II and IV instar larvae of Aedes aegypti. Antibacterial activity was evaluated against a panel of 7 bacteria by agar well diffusion assay. Antiradical activity was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azinobis 3-ethylbenzothiazoline 6-sulfonate (ABTS) free radical scavenging assays.Results: The extract was found to cause dose-dependent mortality of larvae of A. aegypti. The lethal concentration 50 value of extract for II and IV instar larvae was found to be 0.41 and 0.99 mg/ml, respectively. Extract was effective in inhibiting all bacteria. Gram-positive bacteria displayed marked susceptibility when compared to Gram-negative bacteria. Bacillus cereus and Escherichia coli were susceptible to highest and least extent, respectively. Extract scavenged both DPPH radicals and ABTS radicals dose dependently. Extract scavenged ABTS radicals more efficiently (inhibitory concentration [IC50] value 13.51 μg/ml) when compared to DPPH radicals (IC50 value 17.43 μg/ml).Conclusions: The plant N. plumbaginifolia appears to be a promising resource for developing agents with insecticidal, antibacterial, and antiradical activity. The observed bioactivities could be attributed to the presence of phytochemicals which are to be isolated, characterized, and subjected for bioactivity determinations. The plant can be used to prevent arboviral diseases, infectious diseases, and oxidative damage.

Synthesis and larvicidal activities of compounds based on coumarin and dibenzothiophene/carbazole

Based on a rationally conceived pharmacophore model to build a dual-target mosquito larvicide, a family of coumarin-dibenzothiophene or -carbazole hybrids with various substituents on phenyl were synthesized in moderate yields. Larvicidal activity of hybrid molecules were evaluated against fourth instar larvae of Aedes aegypti. Most of the synthesized hybrids displayed moderate to high activity and the activities of coumarin-linked carbazole hybrids were better than those of dibenzothiophene hybrids. The structure–activity relationships revealed that coumarin, dibenzothiophene and carbazole were the key pharmacophore and carbazole derivatives consisting of an electron-withdrawing group in the coumarin–carbazole hybrid molecular structure possess better activity than their corresponding parent compound.

Molecular characterization of indigenous Bacillus thuringiensis strains isolated from Kashmir valley

Bacillus thuringiensis (Bt) being an eco-friendly bioinsecticide is effectively used in pest management strategies and, therefore, isolation and identification of new strains effective against a broad range of target pests is important. In the present study, new indigenous B. thuringiensis strains were isolated and investigated so that these could be used as an alternative and/or support the current commercial strains/cry proteins in use. For this, 159 samples including soil, leaf and spider webs were collected from ten districts of Kashmir valley (India). Of 1447 bacterial strains screened, 68 Bt strains were identified with 4 types of crystalline inclusions. Crystal morphology ranking among the Bt strains was spherical (69.11%) > spore attached (8.82%) > rod (5.88%) = bipyramidal (5.88%) > spherical plus rod (4.41%) > spherical plus bipyramidal (2.94%) = cuboidal (2.94%). SDS-PAGE investigation of the spore–crystal mixture demonstrated Bt strains contained proteins of various molecular weights ranging from 150 to 28 kDa. Insecticidal activity of the 68 indigenous Bt strains against Spodoptera litura neonates showed that Bt strain SWK1 strain had the highest mortality. Lepidopteron active genes (cry1, cry2Ab, cry2Ab) were present in six Bt strains. Further, analysis of a full-length cry2A gene (~1.9 kb) by PCR–RFLP in strain SWK1 revealed that it was a new cry2A gene in Bt strain SWK1 and was named as cry2Al1 (GenBank Accession No. KJ149819.1) using the Bt toxin nomenclature (http://www.btnomenclature.info). Insect bioassays with neonate larvae of S. litura and H. armigera showed that the purified Cry2Al1 is toxic to S. litura with LC50 2.448 µg/ml and H. armigera with LC50 3.374 µg/ml, respectively. However, it did not produce any mortality in third instar larvae of Aedes aegypti, Culex quinquefasciatus and Anopheles stephensi larvae/pupae insects (100 µg/ml) at 28 ± 2 °C and 75 to 85% relative humidity under a photoperiod of 14L:10D.

Photo-induced and phytomediated synthesis of silver nanoparticles using Derris trifoliata leaf extract and its larvicidal activity against Aedes aegypti

Due to the increased development of resistance of vectors against synthetic insecticides and chemical drugs, plant based insecticides serve as promising biocontrol agents for effective vector control. Green approach for the synthesis of nanoparticles has been attained using environmentally safe, non-toxic plant extracts. The present study was aimed to investigate the potent larvicidal activity of silver nanoparticles (AgNPs) produced by Derris trifoliata leaf extract in relation to the various concentrations of methanol and chloroform extracts for 24h against 3rd and 4th instar larvae of Aedes aegypti. AgNPs were synthesized using D. trifoliata leaf extract as reducing and stabilizing agent. Synthesized AgNPs were characterized by UV–Vis spectroscopy, FTIR spectroscopy, SEM, EDX, XRD and HRTEM. The size of AgNPs as estimated from the full width at half-maximum of (200) peak of silver was 16.13nm, the average crystalline size of the synthesized AgNPs was approximately 20nm, which was correlated with the HRTEM results (20nm). SEM and TEM images have shown the formation of polydispersed nanoparticles with an average size of 20nm. The FTIR spectra of AgNPs exhibited prominent peaks at 2360.7, 1606.2, 1095.6 and 785.9cm−1. The spectral peak observed at 1606.2, assigned to stretching vibration (C=O) in carbonyl compounds characterized by the presence of major constituents of flavonoids and terpenoids. The results obtained in FTIR spectroscopy correlated with the GC–MS analysis of methanol and chloroform extracts and indicates the presence of phytosteroids, flavonoids and terpenoids. The highest larvicidal activity was observed for the synthesized AgNPs against the 3rd instar larvae with LC50 values of 5.87mg/l and LC90 of 12.11mg/l, while against 4th instar larvae these values were7.00 and17.76mg/l respectively. The chloroform extracts also showed increased larvicidal activity than methanol extracts against 3rd instar larvae (LC50=54.42mg/l, LC90=140.83mg/l) and 4th instar larvae (LC50=62.47mg/l, LC90=145.06mg/l) of A. aegypti. Besides, the synthesized AgNPs also exhibited potent antibacterial activity against certain food borne pathogens. These results infer that the biologically synthesized AgNPs and organic solvent extracts have the potential to be used as an excellent eco-friendly approach for vector control against A. aegypti.

Bioactivities of a New Pyrrolidine Alkaloid from the Root Barks of Orixa japonica.

A new pyrrolidine alkaloid named (Z)-3-(4-hydroxybenzylidene)-4-(4-hydroxyphenyl)-1-methylpyrrolidin-2-one was isolated from the ethanol extract of the root barks of Orixa japonica. The structure of the new alkaloid was elucidated on the basis of NMR and MS analysis. The compound exhibited larvicidal activity against the fourth instar larvae of Aedes aegypti (LC50 = 232.09 μg/mL), Anopheles sinensis (LC50 = 49.91 μg/mL), and Culex pipiens pallens (LC50 = 161.10 μg/mL). The new alkaloid also possessed nematicidal activity against Bursaphelenchus xylophilus (LC50 = 391.50 μg/mL) and Meloidogynein congnita (LC50 = 134.51 μg/mL). The results indicate that the crude ethanol extract of O. japonica root barks and its isolated pyrrolidine alkaloid have potential for development into natural larvicides and nematicides.

Evaluation of Silver Nanoparticle Toxicity of Coleus aromaticus Leaf Extracts and its Larvicidal Toxicity against Dengue and Filariasis Vectors

Mosquitoes in the larval stage are attractive targets for pesticides as mosquitoes breed in water, and thus, it is easy to deal with them in this habitat. The use of conventional pesticides, in the water sources, introduces many risks to people and environment. Natural pesticides, especially those derived from plants, are more promising in this aspect. Plants are rich in secondary metabolites which are an efficient source for natural pesticide. Nanoparticle-conjugated plant extracts increase the botanical of plant extracts and are hence attractive sources for mosquito control. The present study investigates the plant-mediated synthesis of silver nanoparticles using the Coleus aromaticus leaf extracts against dengue and filariasis mosquito vectors. Silver nanoparticle-conjugated plant extracts were characterized by Ultraviolet-Visible spectroscopy, scanning electron microscopy, Energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. The size of the silver nanoparticles was 262.7 nm. The larvicidal potential of solvent leaf extracts of Coleus aromaticus and synthesized silver nanoparticles using aqueous leaf extract against fourth instar larvae of Aedes aegypti and Culex quinquefasciatus was assessed. Larvae were exposed to varying concentrations of plant extracts and synthesized AgNPs plant extracts post 24 h; mosquito larvae showed maximum mortality in leaf extracts synthesized AgNPs against the fourth instars larvae of Ae. aegypti and Cx. quinquefasciatus. These results suggest that the synthesized AgNPs from leaf extracts have a higher larvicidal potential as compared to crude solvent extracts thus making them an effective combination for controlling dengue and filariasis vectors.

Pemanfaatan Jeruk Purut (Citrus Hystrix) Sebagai Biolarvasida

Absctract: Citrus hystrix, Biolarvicides. Insectisides and pestisides were used as larvicides to control mosquito vector Aedes aegypti particularly. Some research suggested there had been a larvae resistance to pesticides. Biolarvicides with basic ingredients plant was another alternative that can be used. Lime (Citrus hystrix) was one of plants that often used as biolarvicides, both lits fruit and leaves. This paper aimed to know about chemical compound in lime and its potential as biolarvicidal. Research methods was literature review from several research journals. The results showed that the presence of coumpounds were essential oil, flavonoids, saponins, terpeesn, limonoids, citronellal, linalool, citronellol, acetate citronelil, kariofilin and geraniol. LC50 of lime leaves as biolarvicides againts the third instar larvae of Aedes aegypti was 279.882 ppm, biolarvicides oxicity values (LC90) was 4000 ppm with the lethal time (LT90) was 12.67 hours. Based on results of this study concluded that the presence of the chemical content of Citrus hystrix plant potential as biolarvicides.

TOXICITY OF HEXANIC AND METHANOLIC FRACTIONS FROM Copaifera reticulata DUCKE (LEGUMINOSAE – CAESALPINOIDEA) AGAINST Aedes aegypti LINNAEUS (DIPTERA – CULICIDAE), IN FIELD ASSAYS

Testes foram realizados no meio urbano, em condições ambientais, nos três criadouros artificiais mais comuns (pneu, plástico e vidro) para verificar a eficácia das frações hexânicas (CRH) e metanólicas (CRM) do óleo-resina de Copaifera reticulata (Ducke) (Leguminosae-Caesalpinoideae) sobre larvas de 3° estádio de Aedes aegypti (Linnaeus) (Diptera: Culicidae). A atividade larvicida foi verificada em todos os criadouros, mas apresentou diferenças de acordo com o tipo de recipiente. Os criadouros de vidro e plástico interferiram menos na atividade larvicida do que o pneu. A fração mais promissora foi a CRH1, que apresentou CL90 igual a 18,2 ppm, 18,8 ppm e 42,8 ppm, respectivamente, para os recipientes de plástico, vidro e pneu.