Instar Larvae Of Cx Research Articles

Larvicidal efficacy of Vangueria spinosa Roxb. (Rubiaceae) leaf extracts against filarial vector Culex quinquefasciatus

Culex quinquefasciatus is the transmitter of some dreadful vector-borne diseases. Such diseases can be controlled by managing the vector population. In this study, the mosquito larvicidal activity of the leaf extracts of a deciduous shrub Vangueria spinosa was evaluated for the first time. Larval mortalities were assessed using crude and different solvent extracts of young leaves of V. spinosa with different concentrations following standard methods. Thin-layer chromatography was done to characterize the major bioactive components liable for larval mortality. Cent percent mortality of the third instar larvae of Cx. quinquefasciatus was recorded at 2.5% concentration of crude extract within 48 hrs. Chloroform: Methanol extract was found to be the deadliest and 100% mortality of third instar larvae was reached in 48 hrs at 50 ppm concentration. The active ingredient which seems to be mainly responsible for larval mortality was steroidal in nature. LC50 of the fraction was calculated as 13.34 ppm for third instar larvae in 24 hrs. No significant effect of these extracts was noted on non-target organisms. So, the leaf of V. spinosa can be used as a potential source for the preparation of mosquito larvicide.

Evaluation of mosquitocidal potency of leaves and fruits extracts of Phyllanthus acidus L. against filarial vector Culex quinquefasciatus Say

The present piece of work was done to carry out larvicidal, pupicidal, adulticidal, and repellent activities of crude extracts of mature leaf and fruit extract of Phyllanthus acidus against filarial vector Culex quinquefasciatus. The percentage mortality of 1st instar stages of Cx. quinquefasciatus at 0.7% concentration was considerably higher (p < 0.05), followed by second, third and fourth instars larvae. Whereas crude extract of fruits showed 100% mortality at 0.9% concentration in case of first instar larvae of Cx. quinquefasciatus after 24 h of contact. The lowest LC50 value observed was 0.26 ml and 0.34 ml against the first instar larval stages of Cx. quinquefasciatus after exposure of 24 hours in crude leaf and fruit extract of P. acidus, respectively. In pupicidal bioassay, the crude leaves extract of P. acidus exhibited pupicidal potency with LC50 values of 7.463% after 24 h. The extract from fresh leaves of P. acidus revealed repellency against the mature females of Cx. quinquefasciatus with 94% protection. In adulticidal activity, after 24 h of exposure there is 93.3% death of adult mosquitoes of Cx. quinquefasciatus observed. ANOVA (three-way factorial) was done for both the crude extracts of plant parts and it showed a substantial variance in larval mortality (p

Agro-waste derived compounds (flax and black seed peels): Toxicological effect against the West Nile virus vector, Culex pipiens L. with special reference to GC-MS analysis.

The development of different approaches to use agricultural residues as a source of high value-added products, become a must, especially after the problems emerged due to their accumulation. This contribution demonstrates the potential of agricultural residues, Linuim usitatissium (flax seed) and Nigella sativa (black seed) peels, as raw materials for the production of bioactive products, botanical insecticides, against Cx. pipiens, with deep analysis to their chemical constituents by gas chromatography-mass spectrometry, the larvicidal efficacies of the three crude extracts (methylene chloride, petroleum ether and methanol 70%) from the two plant waste peels were evaluated for the first time against the late third instar larvae of Cx. pipiens. Results indicated different lethal doses in larvae depending on the efficacy of organic solvent used. For both compounds methanol 70% extracts produced the highest dry yield. The most efficient solvent is petroleum ether in case of both flax and Black seed peels. Petroleum ether extract exhibited the highest toxicity against Cx. pipiens with an LC50 of 69.6383 ppm. The same results for black seed indicated that petroleum ether was the most efficient against Cx. pipiens with an LC50 of 40.7748 ppm. The study revealed for the first time the type of phytochemical constituents presents in peels of flax and black seeds using GC–MS analysis which revealed twenty-eight constituents among extracts of flax and black seed peels ranging from to 58.8711% to 99.99% of the total extracts. GC–MS profiling showed that a five constituents, 9-2-Methyl-Z, Z-3, 13 octadecadienol (terpenoid), 9,17-Octadecadienal, (Z)-, Nonanoic acid, 9-oxo-, methyl ester, 9,12-Octadecadienoic acid Z,Z and Octasiloxane, 1,1,3,3,5,5,7,7,9,9,11,11,13,13,15,15-hexadecamethyl- have insecticidal activity beside many other biological activities as recorded from a variety of botanical extracts. While the constituents like Hexadecanoic acid, methyl ester and cis-9-Hexadecenal, both of them are larvicidal, cis-Vaccenic acid and 9-Oxononanoic acid showing only an insecticidal activity beside Undecanoic acid the mosquito repellent. The other six constituents Linoelaidic acid, Oleic Acid, Z-2-Octadecen-1-ol, 1-Methoxy-3-hydroxymethylheptane, Cis-11,14–Eicosadieonic acid-methyl ester and Heptasiloxane, 1,1,3,3,5,5,7,7,9,9,11,11,13,13-tetradecamethyl- are constituents of other plant extracts which showed as a whole an insecticidal activity.

Larvicidal efficacy of the mature leaf extract of Cajanus cajan against the vector of Japanese encephalitis

Vector borne diseases can be controlled by managing the mosquito population. So the present study was done to evaluate larvicidal activities of Cajanus cajan mature leaf extracts against the Japanese encephalitis vector Culex vishnui. Crude and three different solvent extracts of C. cajan leaves were applied for larvicidal bioassay against the all instars larvae of Cx. vishnui. For statistical justifications log probit, regression and ANOVA analyses were performed. Non-target organisms were also evaluated against crude and ethyl acetate solvent extract of mature leaves. The IR analysis and GC-MS analyses were carried out to find out the active ingredient. 0.5% concentration of crude extract showed highest larval mortality after 72 h of exposure. Amongst the three tested solvent extracts namely n-Hexane, ethyl acetate and chloroform: methanol (1:1 v/v), ethyl acetate extract exhibited the most potent larvicidal activity. In ethyl acetate extract 100% mortality was found in 100 ppm concentration against 1st instar larvae after 72 h of exposure. Chemical characterization revealed that the active ingredient belongs to the flavonoids group of compound which might be responsible for larval toxicity. However, the bioassay against the non-target organisms revealed that, they were mostly safe to the extracts. The results support that C. cajan mature leaves can be used as an ecofriendly larvicidal agent against the Cx. vishnui in near future.

Control of Japanese encephalitis by active principles, 3-(2-Hydroxyphenoxy)-1, 2-propanediol isolated from n-hexane extract of leaf of Mesua ferrea Linn.

Japanese encephalitis is a vector borne disease and the best procedure for control of this disease is control of vector population. Now a day use of phyto-chemicals more preferred over use of chemical insecticides. Isolation, purification and determination of chemical structures of bioactive compounds were done successfully from n-hexane extract of leaf of M. ferrea. The compounds shows better potentiality to control Cx. vishnui 3rd instars larvae. n-hexane extract of leaf of M. ferrea was prepared by Sohxlet apparatus and further used for bioassay against 3rd instars larvae of Cx. vishnui. n-hexane extract was further fractioned by Thin layer chromatography to isolate bioactive compounds. From different band of TLC, bioactive compounds bearing band was isolated by bioassay test. Structures of active principles were determined by FTIR, gas chromatography, mass spectrometry and with the help of library data list. Cent percent mortality of Cx. vishnui larvae was recorded at 45 ppm concentration of n-hexane extract of M. ferrea after 72 h of exposure. In isolated bioactive compounds 3-(2-Hydroxyphenoxy)-1, 2-propanediol is one of predominant compound, may be responsible for mortality of Cx. vishnui larvae. LC50 value for Cx. vishnui 3rd instars larvae of active compound are 26.76, 25.64 and 20.32 ppm for 24 h, 48 h and 72 h respectively. No mortality were recorded when sub lethal concentration (LC50) of 24 h of bioactive compound applied on non-target organisms i.e. Chironomus circumdatus, Daphnia, Diplonychus etc. The compound i.e. 3-(2-Hydroxyphenoxy)-1, 2-propanediol is predominant compound of active principles and its chemical structure is determine which is major component of n-hexane extract of leaf of M. ferrea. These bioactive principles are safe for other organisms (non-target) those share the same natural habitat.

IGR Activity of Three Indigenous Plants belonging to Asteraceae Family and its Potential Role on Control of Filarial Vector, Culex quinquefasciatusSay (Diptera: Culicidae)

Background: Insect Growth Regulatory and larvicidal role of three indigenous plants belonging to the family Asteraceae is tested against the filarial vector, Culex quinquefasciatus Say. Methods: IGR and larvicidal bioassays were conducted using methanol and water extracts of the selected plants such as Blumea mollis, Vernonia cinerea and Centratherum punctatum against I instar larvae of Cx. quinquefasciatus. Result: Lethal concentrations (LC50 and LC90) were estimated for methanol and aqueous extracts of the selected plants. Treatment with methanolic extracts exhibited prolonged larval and pupal duration, when compared to control. Total developmental period was also significantly extended. The larvae treated with aqueous extracts showed shortening of larval and pupal durations. Conclusions: The present study highlights the importance of plantbased materials and their efficacy to control the mosquito vectors with special to Culex quinquefasciatus. Treatment with methanol extracts of the selected plants showed extension of larval duration where as aqueous extracts show precocenes like activity and the total developmental period shortened with the emergence of almost 90 % of the treated larvae. How to cite this article:Ahalya SR, Pushpalatha E. IGR Activity of Three Indigenous Plants belonging to Asteraceae Family and its Potential Role on Control of Filarial Vector, Culex quinquefasciatus Say (Diptera: Culicidae). J Commun Dis 2020; 52(2): 18-23. DOI: https://doi.org/10.24321/0019.5138.202014

Effect of Pb, Cd and Cu on survival and development of Culex quinquefasciatus (Diptera: Culicidae)

ABSTRACTThe present research aimed to determine the lowest levels of three heavy metals (Pb, Cd and Cu) to which the larvae of Southern House Mosquito, Culex quinquefasciatus are susceptible in water. The study also aimed to investigate the effects of these heavy metals on the development of Cx. quinquefasciatus at concentrations set by Pakistan Environmental Protection Agency (Pak-EPA) as permissible levels for liquid industrial effluents. The 2nd instar larvae of Cx. quinquefasciatus were exposed to different concentrations of Pb, Cd and Cu and their effects on oviposition preference, egg hatching rate and larval development were studied. The LC50 values of Pb, Cd and Cu were 12.6, 6.3 and 2.6 ppm, respectively. Gravid female mosquito adults deposited a significantly lower number of egg rafts in containers containing 0.50 ppm Pb or 1.0 ppm Cu in water. Each of the heavy metals in water resulted in significantly (p < 0.05) lower egg hatching rate, prolonged time to pupation, lower pupation rate, prolonged time to adult emergence, lower adult emergence rate and higher female to male ratio. It is concluded that the 2nd instar larvae of Cx. quinquefasciatus are susceptible to Pak-EPA permissible levels of Pb, Cd and Cu in municipal and liquid industrial effluents.

Mosquitocidal Activity of the Pale Brittle Stem Mushroom, Psathyrella candolleana (Agaricomycetes), against Three Vector Mosquitoes.

The aim of the present study was to screen for mosquito larvicidal activity of methanol extract of a wild mushroom Psathyrella candolleana against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. Larvae and eggs were exposed to four different concentrations (62.5, 125, 250, and 500 ppm) and mortality was assessed 24 and 120 h after treatment. The LC50 and LC90 values of the extract were calculated. Methanol crude extract of P. candolleana showed good larvicidal activity against the third instar larvae of Cx. quinquefasciatus with LC50 and LC90 values of 166.713 and 259.17 ppm, respectively, after 24 h of exposure. No larvicidal activity was observed against Ae. aegypti and An. stephensi. The methanol extract of P. candolleana presented 88% ovicidal activity against Cx. quinquefasciatus at 500 ppm concentration 120 h after treatment. The active methanol extract was tested for toxicity against non-target organism and found was to have no toxicity. Histopathological studies of the treated larvae revealed serious damages to the midgut cells. The mushroom species was confirmed by 5.8S rRNA sequence and phylogenetic tree was constructed. These results suggest that the methanol extract of P. candolleana could be used in Cx. quinquefasciatus control programs as a new eco-friendly larvicide.

Susceptibility of third instar larvae of Culex quinquefasciatus Say (Culicidae: Insecta) against some commercial organophosphate and pyrethroid insecticides

Eight commercial insecticides-chlorpyrifos, bifenithrin, fenitrothion, cypermethrin, deltamethrin, cyhalothrin, dimethoate and malathion under the brand name of Dursban 20 EC, Bifenithrin 20 EC, Sumithion 50 EC, Relothrin 10 EC, Marker 2.5 EC, Reeva 2.5 EC, Tafgar 40 EC and Hilthion 57 EC, respectively were tested in laboratory at room temperature to evaluate the effective level against 3rd instar larvae of Culex quinquefasciatus Say from Savar area of Dhaka. The LC50 values for chlorpyrifos, bifenithrin, fenitrothion, cypermethrin, deltamethrin, cyhalothrin, dimethoate and malathion were 0.127, 297.474, 0.308, 0.327, 0.198, 0.189, 0.054 and 0.031 ppm respectively and their corresponding LC90 values were found to be 0.984, 2582, 0.041, 3.298, 0.728, 1.705, 0.192 and 0.030 ppm respectively. The relative potency of these insecticides tested to the larvae was found in respect to their LC50 values in the order of Hilthion 57 EC (malathion)&gt; Tafgar 40 EC (dimethoate)&gt; Dursban 20 EC (chlorpyrifos)&gt; Reeva 2.5 EC (cyhalothrin)&gt; Marker 2.5 EC (deltamethrin)&gt; Sumithion 50 EC (fenitrothion)&gt; Relothrin 10 EC (cypermethrin)&gt; Bifenithrin 20 EC. However, the relative potency of these insecticides tested to the larvae was found in respect to their LC90 values in the order of Hilthion 57 EC (malathion)&gt; Sumithion 50 EC (fenitrothion)&gt; Marker 2.5 EC (deltamethrin)&gt; Dursban 20 EC (chlorpyrifos)&gt; Tafgar 40 EC (dimethoate)&gt; Reeva 2.5 EC (cyhalothrin)&gt; Relothrin 10 EC (cypermethrin)&gt; Bifenithrin 20 EC. Taken together, the insecticide-malathion (Hilthion 57 EC) was found to be the most effective against the third instar larvae of Cx. quinquefasciatus in Savar area.&#x0D; Jahangirnagar University J. Biol. Sci. 7(2): 21-32, 2018 (December)

Larvicidal effect of Clinopodium macrostemum essential oil extracted by microwave-assisted hydrodistillation against Culex quinquefasciatus (Diptera: Culicidae).

In the present study, we determined the chemical composition of Clinopodium macrostemum essential oil obtained by microwave-assisted hydrodistillation and its effect on the growth and development of Culex quinquefasciatus mosquito larvae. The essential oil compounds were identified by gas chromatography-mass spectrometry analysis, and bioassays were conducted to evaluate the influence on the developmental stages of early second instar larvae of Cx. quinquefasciatus until the emergence of adults, using essential oil concentrations of 50, 100, 200, 400, and 800mg/L. The gas chromatography-mass spectrometry analyses revealed that the leaf essential oil of C. macrostemum contained 32 compounds and the major chemical compounds identified were linalool (55.4%), nerol (6.4%), caryophyllene (6.25%), menthone (5.8%), geraniol acetate (4.1%), terpineol (3.7%), and pulegone (2.8%). The essential oil yield obtained by microwave-assisted hydrodistillation was 0.8% at 20 min. The treatments showed lethal concentrations (LC50 and LC90) of 22.49 and 833.35mg/L, respectively, after the final measurement of the total number of dead larvae (second, third, and fourth instars), and LC50 and LC90 of 6.62 and 693.35mg/L, respectively, at the end of the experimental period. The essential oil inhibited the growth and development of the mosquito larvae by 32% (relative growth index = 0.68) at 50mg/L, and up to 47% (relative growth index = 0.53) at 800mg/L. The present study demonstrated the larvicidal effect of C. macrostemum essential oil on Cx. quinquefasciatus, which can be attributed to the oxygenate compounds obtained by the extraction method.

Larvicidal, Histopathological Efficacy of Penicillium daleae against Larvae of Culex quinquefasciatus and Aedes aegypti Plus Biotoxicity on Artemia nauplii a Non-target Aquatic Organism.

Mosquitoes can transmit the terrible diseases to human beings. Soil-borne fungal products act as potential source for low-cost chemicals, used for developing eco-friendly control agents against mosquito-vector borne diseases. The prime aim of study was to check the larvicidal potential of fungus mycelia (by ethyl acetate solvent) extract from Penicillium daleae (KX387370) against Culex quinquefasciatus and Aedes aegypti and to test the toxicity of brine shrimp Artemia nauplii, by observing the physiological activity. The ethyl acetate extract of P. daleae mycelia (after 15 days) from Potato dextrose broth (PDB) medium revealed better result with least LC50 and LC90 values of I-IV instars larvae of Cx. quinquefasciatus (LC50 = 127.441, 129.087, 108.683, and 93.521; LC90 = 152.758, 158.169, 139.091, and 125.918 μg/ml) and Ae. aegypti (LC50 = 105.077, 83.943, 97.158, and 76.513; LC90 = 128.035, 106.869, 125.640, and 104.606 μg/ml) respectively. At higher concentration (1000 μg/ml) of extracts, mortality begins at 18 h of exposure and attained 100% mortality after 48 h exposure. Overall, the activity was depends on the dose and time of exposure to the extracts. The stereomicroscopic and histopathological analysis of Ae. aegypti and Cx. quinquefasciatus larvae treated with mycelium ethyl acetate extract showed complete disintegration of abdominal region, particularly the midgut and caeca, loss of cuticular parts and caudal hairs. Morphological characterization of the fungi was performed and taxonomically identified through 5.8s rDNA technique. The phylogenetic analysis of rDNA sequence was carried out to find out the taxonomic and the evolutionary sketch of isolate in relation to earlier described genus Penicillium. Behavior and swimming speed alteration was analyzed together with mortality. The results of the experiment indicates that swimming behavior recorder (SBR) is a appropriate tool to detect individual swimming speed of the A. nauplii organisms, since the values have been obtained in accordance with control monitored results showed the 2.75 mm s-1 and after 24 h treated found to be 0.72 mm s-1, respectively. The extract-exposed to A. nauplii showed changes in body structures, i.e., intestine enlargement, eye formation, outer shell malformations and loss of antennae. In the present study, we aimed to investigate the toxicity of the ethyl acetate extract of P. daleae on A. nauplii larvae by performing the mortality, behavior and alterations in swimming responses. This is the first time report on the larvicidal efficacy of P. daleae ethyl acetate extract against Cx. quinquefasciatus and Ae. aegypti larvae.

Larvicidal effectiveness of acethonilic and methanolic Ipomoea cairica extract using two extraction methods and its effects on the morphology of Culex quinquefasciatus Say mosquito

Plants produce a rich source of chemicals, drugs and secondary metabolites that can act as insect killer. The larvicidal activity of various part of Ipomoea cairica extracts was evaluated against Culex quinquefasciatus. The highest percentage of yield extract was given by Soxhlet with acetone solvent for all of the different plant parts. While, maceration technique only provided 1/3 of the yield compared to Soxhlet technique. Using 24 h larvicidal bioassay technique, third instar larvae of Cx. quinquefasciatus were exposed to concentrations ranging from 10 to 600 ppm of the acetone and methanol extracts of I. cairica from leaves, stem and flower bud. Acethonilic extract of I. cairica leaves was extracted using a Soxhlet apparatus which exhibited the most promising larvicidal activity against Cx. quinquefasciatus larvae with significantly lower LC50 value of 110.65 ppm, meanwhile methanolic leaves extract exhibited LC50 value of 143.47 ppm. Larvae exposed to the I. cairica extracts for 24 h showed morphological malformation that included a detachment of thorax, disruption of the digestive tract and pigmentation of cuticle on their death. Thus, suggested that I. cairica plant extract, especially acethonilic leaves extract can be considered as one of plant-derived insecticides for control of Cx. quinquefasciatus, a vector of filariasis.

Larvicidal Efficacy of Root and Stem Bark Extracts of the Plant, &lt;i&gt;Annona reticulata&lt;/i&gt; against Filarial Vector, &lt;i&gt;Culex quinquefasciatus&lt;/i&gt;

The present study assessed larvicidal efficacy of different concentrations of chloroform: methanol (v/v 1:1), acetone, and ethanol extracts of root and stem bark of Annona reticulata L. (Annonaceae) against early 3 rd instar larvae of Culex quinquefasciatus Say, 1823 ( Cx. quinquefasciatus ) up to 72 hours. Among all the solvent extracts used, chloroform: methanol (v/v 1:1) root and stem bark extracts of the plant showed highest larvicidal activity. Further, the effect of chloroform: methanol (v/v 1:1) root and stem bark extracts of the plant was investigated on early 1 st – 4 th instars larvae of Cx. quinquefasciatus . Early 1 st - 3 rd instars larvae of Cx. quinquefasciatus showed 100% mortality with remarkably very low concentrations of chloroform: methanol (v/v 1:1) root and stem bark extracts. Non- target organisms were non responsive to chloroform: methanol (v/v 1:1) solvent root and stem bark extracts. So, chloroform: methanol (v/v 1:1) root as well as stem bark extracts of A. reticulata can effectively be used as potential sources to control Cx. quinquefasciatus population.

Studies on Larvicidal Activity of Some Plant Extracts against Filarial Vector &lt;i&gt;Culex quinquefasciatus&lt;/i&gt;

Background & Objectives: Vector control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative in near future. In the present study, crude plant extracts of 32 commonly available plants were evaluated at different concentrations against third instars larvae of Culex quinquefasciatus to establish their mosquito larvicidal activity. Methods : Three different Concentrations (0.1, 0.5 and 1.0%) of crude extracts were prepared from selected plants and observed larval mortality after 24h, 48h & 72h of post exposure against third instars larvae of Cx. quinquefasciatus . LC 50 and LC 90 were determined by using log-probit analyses. Effects on non target organisms were also tested. Result : Among the tested concentrations, highest mortality was recorded at 1% concentration of crude extract within 72 hours of exposure in all plant extracts. In laboratory based larvicidal bioassay, lowest LC 50 and LC 90 values were recorded in fruit extracts of Solanum nigrum and Solanum sisymbrifolium respectively. Mosquito larvicidal property of Clerodendrum viscosum , Cleome viscosa, Alangium salvifolium, Murraya k oenigii, Polyalthia longifolia and Derris indica were also satisfactory. Tested non-target organisms were entirely safe against the tested concentrations during study. Interpretation & Conclusion : Among tested 32 plants, the crude extracts ofeight plantshave the potent larvicidal activity against filarial vector Cx. quinquefasciatus without harmful effect on non target organisms.

Larvicidal Efficacy of Fruit Peel Extracts of &lt;i&gt;Citrus maxima&lt;/i&gt; against &lt;i&gt;Culex quinquefasciatus&lt;/i&gt;

Crude, and three different solvents, viz., n- hexane, ethyl acetate, and methanol fruit peel extracts of Citrus maxima Merr. ( C. maxima ) were applied at dose dependent manner for larvicidal bioassay against Culex quinquefasciatus Say, 1823 ( Cx. quinquefasciatus ) mosquito. All instars larvae were used for larvicidal bioassay of crude fruit peel extract and only 3 rd instar larvae were used for larvicidal bioassay of different solvent extracts. Log-probit analyses along with Regression equations and R 2 values were determined for larvicidal activity of both crude and different solvent extracts. An ANOVA analysis was carried out to justify the statistical significance. Qualitative phytochemical analyses were done. n-Hexane fruit peel extract was also applied on non target organisms. Crude fruit peel extract of C. maxima showed strong lethal activity against all instars larvae of Cx. quinquefasciatus . 1 st instar larvae were most susceptible to crude fruit peel extract. 1 st instar larvae showed 100% mortality only at 0.2% concentration of crude fruit peel extract after 72 h of exposure. 100% mortality of 3 rd instar larvae were observed at 400 ppm concentration of n-hexane fruit peel extract after 24 h of exposure whereas, ethyl acetate and methanol fruit peel extracts showed 100% mortality at 800 ppm concentration after 72 and 24 h of exposure respectively. LC 50 values of n-hexane, ethyl acetate and methanol fruit peel extracts were 204.60, 640.95, and 336.36 ppm, respectively against 3 rd instar larvae after 24 h of exposure. No mortality was observed on control treatments. Fruit peel extract contained different phytochemical constituents. Non-target organisms did not show any abnormal activity and mortality.

Larvicidal Potentiality of Root Extracts of &lt;i&gt;Annona reticulata&lt;/i&gt; Linn. Against the Filarial Vector &lt;i&gt;Culex quinquefasciatus&lt;/i&gt; Say (Diptera: Culicidae)

Present study was undertaken to evaluate the mosquito larvicidal potentiality of root extracts of Annona reticulata Linn. ( A. reticulata ), family Annonaceae against filarial vector Culex quinquefasciatus Say, 1823 ( Cx. quinquefasciatus ). Petroleum ether, hexane, and ethyl acetate root extracts of the plant were examined to established their larvicidal potentiality against 3 rd instar larvae of Cx. quinquefasciatus mosquito species. Crude and only ethyl acetate root extracts of the plant at different concentrations were examined on 1 st - 4 th instars larvae of Cx. quinquefasciatus . LC 50 value of ethyl acetate extract after 24 h of exposure against 3 rd instar larvae of Cx. quinquefasciatus were also examined on some non target organisms. Phytochemical analyses of the root extracts of A, reticulata were also investigated. 100% mortality were noticed at very low concentrations of petroleum ether, hexane, and ethyl acetate root extracts of A. reticulata against 3 rd instar larvae of Cx. quinquefasciatus . LC 50 and LC 90 values of ethyl acetate root extract was lower than petroleum ether and hexane root extracts after 24, 48, and 72 h of exposure. Crude and ethyl acetate root extracts showed excellent larvicidal activity against Cx. quinquefasciatus mosquito species. 100% mortality was observed at very low concentration for crude and ethyl acetate root extracts. LC 50 and LC 50 values gradually decreased with time of exposure for crude and ethyl acetate root extracts of A. reticulata . No mortality and sluggishness were observed in control experiments as well as on examined non target organisms. Phytochemical analyses of root extracts of the plant revealed the presence of different secondary metabolites. So crude and ethyl acetate root extracts of A. reticulata can effectively be used for larval mortality against Cx. quinquefasciatus mosquito species at a very low concentration.

Evaluation of Larvicidal Efficacy of Acetone Leaf Extracts of &lt;i&gt;Annona reticulata&lt;/i&gt; Linn. Against &lt;i&gt;Aedes aegypti, Anopheles stephensi&lt;/i&gt; and &lt;i&gt;Culex quinquefasciatus&lt;/i&gt; (Diptera: Culicidae)

The present study was designed to examine the larvicidal property of acetone leaf extracts of Annona reticulata L. ( A. reticulata ), (family: Annonaceae) against 1 st to 4 th instars larvae of three dreadful mosquitoes namely Aedes aegypti L., 1762 ( Ae. aegypti ), Anopheles stephensi Liston, 1901 ( An. stephensi ) and Culex quinquefasciatus Say, 1823 ( Cx. quinquefasciatus ). Cent percent mortality was observed at 12 ppm concentration in 1 st , 2 nd and 3 rd instars larvae of Ae. Aegypti , where as 9 ppm concentration showed 100% mortality in 1 st , 2 nd and 3 rd instars larvae of An. stephensi after 72 h of exposure. At 6 ppm concentration, 100% mortality was observed in 1 st instar larvae after 24 h of exposure and in 2 nd and 3 rd instars larvae of Cx. quinquefasciatus after 48 h of exposure. In the 72 h bioassay experiment, LC 50 and LC 90 values progressively decreased with the increase in exposure period, having the lowest values at 72 h of exposure. Among the three mosquitoes, Cx. quinquefasciatus proved to be most susceptible to acetone leaf extract of A. reticulata . Some non target organisms were found to be non-responsive to the bioactive extract when exposed. So, acetone leaf extract of A. reticulata was proved to be an efficient larvicidal agent against 3 important vectors like Ae. aegypti, An. stephensi and Cx. quinquefasciatus .

Mosquito larvicidal potential of ethanol leaf extract of the plant, &lt;i&gt;Annona reticulata&lt;/i&gt; L. &lt;i&gt;against Aedes aegypti&lt;/i&gt; L. and &lt;i&gt;Culex quinquefasciatus&lt;/i&gt; Say (Diptera: Culicidae)

The larvicidal potential of ethanol leaf extract of Annona reticulata L. (A. reticulata ), ( Annonaceae) was evaluated against 1st - 4th instars larvae of Aedes aegypti L. ( Ae. aegypti ) and Culex quinquefasciatus Say ( Cx. quinquefasciatus ) mosquitoes at 24, 48 and 72 h exposure. The extract was found more effective against Cx. quinquefasciatus than Ae . aegypti larvae and its LC 50 and LC 90 values gradually decreased with increased period of exposure. LC 50 values of the extract recorded after 24 h of exposure were 0.5021, 2.9374, 4.2048, 6.2245 ppm respectively against 1st- 4th larvae of Cx. quinquefasciatus and 6.8839, 5.9929, 14.5745, 19.8836 ppm against Ae. aegypti larvae. No mortality and any abnormal behavior up to 72 h post exposure were observed in aquatic non target organisms viz ., Chironomus circumdatus larvae, Diplonychus annulatum and tadpoles of frog when exposed to 24 h LC50 dose of the extract against 3rd instar larvae of Cx. quinquefasciatus . In conclusion, the ethanol leaf extract of A. reticulata exhibited excellent larvicidal activity against Cx. quinquefasciatus and Ae. aegypti mosquitoes.

Larvicidal Activity of Colocasia esculenta, Eclipta prostrata and Wrightia tinctoria Leaf Extract Against Culex quinquefasciatus

Control of mosquitoes by using chemical insecticides creates several problems including development of resistance. This leads to find out alternative methods via plant products. Viewing this in mind, methanolic extracts of Colocasia esculenta, Eclipta prostrata and Wrightia tinctoria leaves were tested against II, III, IV instars and pupa of filarial vector Culex quinquefasciatus. The LC50 value obtained for IV instar larvae of Cx. quinquefasciatus is 165.697 ppm for C. esculenta while it is 114.257 ppm for E. prostrata and 210.298 ppm for W. tinctoria. Of the three plants studied E. prostrata is most effective in controlling mosquito larvae than the others.

Mosquito larvicidal and ovicidal properties of Pithecellobium dulce (Roxb.) Benth. (Fabaceae) against Culex quinquefasciatus Say (Diptera: Culicidae)

Objective: To assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant, Pithecellobium dulce (P. dulce) against filariasis vector mosquito, Culex quinquefasciatus (Cx. quinquefasciatus). Methods: Twenty five early third instar larvae of Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol of WHO (2005). The larval mortality was observed after 24 h of treatment. The ovicidal activity was determined against Cx. quinquefasciatus mosquito eggs to various concentrations ranging from 100-750 mg/L under the laboratory conditions. Results: The methanol extract of the leaves and seed of P. dulce was the most effective against the larvae with LC50 and LC90 values 164.12 mg/L, 214.29 mg/L, 289.34 mg/L and 410.18 mg/L being observed after 24 h of exposure. The efficacy of methanol was followed by that of the ethyl acetate, chloroform, benzene and hexane extracts. The mean percent hatchability of the egg rafts were observed after 48 h of treatment. About 100% mortality was observed at 500 mg/L for leaf and 750 mg/L for seed methanol extracts of P. dulce. Conclusions: From the results, it can be concluded that the larvicidal and ovicidal effect of P. dulce against Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.