Predatory efficiency of the water bug Sphaerodema annulatum on mosquito larvae (Culex quinquefasciatus) and its effect on the adult emergence

2004 ◽  
Vol 95 (2) ◽  
pp. 169-172 ◽  
Author(s):  
G ADITYA
Keyword(s):  
Culex Quinquefasciatus ◽  
Adult Emergence ◽  
Mosquito Larvae ◽  
Predatory Efficiency

RNAi-Mediated Screening of Selected Target Genes Against Culex quinquefasciatus (Diptera: Culicidae)

2021 ◽  
Author(s):  
Sayed M S Khalil ◽  
Kashif Munawar ◽  
Azzam M Alahmed ◽  
Ahmed M A Mohammed
Keyword(s):  
Culex Quinquefasciatus ◽  
Target Genes ◽  
Mosquito Control ◽  
Larval Mortality ◽  
Adult Emergence ◽  
Lethal Effect ◽  
Delivery Methods ◽  
Valley Fever ◽  
Wide Range ◽  
Lethal Genes

Abstract Culex quinquefasciatus, a member of the Culex pipiens complex, is widespread in Saudi Arabia and other parts of the world. It is a vector for lymphatic filariasis, Rift Valley fever, and West Nile virus. Studies have shown the deleterious effect of RNA interference (RNAi)-mediated knockdown of various lethal genes in model and agricultural pest insects. RNAi was proposed as a tool for mosquito control with a focus on Aedes aegypti and Anopheles gambiae. In this study, we examined the effect of RNAi of selected target genes on both larval mortality and adult emergence of Cx. quinquefasciatus through two delivery methods: soaking and nanoparticles. Ten candidate genes were selected for RNAi based on their known lethal effect in other insects. Disruption of three genes, chitin synthase-1, inhibitor of apoptosis 1, and vacuolar adenosine triphosphatase, resulted in the highest mortality among the selected genes using the two treatment methods. Silencing the other seven genes resulted in a medium to low mortality in both assays. These three genes are also active against a wide range of insects and could be used for RNAi-based mosquito control in the future.

scholarly journals Effects of ivermectin on Culex quinquefasciatus larvae

1996 ◽  
Vol 38 (4) ◽  
pp. 293-298 ◽  
Author(s):  
Ricardo Miguel Costa de Freitas ◽  
Mágda de Abreu Faria ◽  
Stênio Nunes Alves ◽  
Alan Lane de Melo
Keyword(s):  
High Mortality ◽  
Culex Quinquefasciatus ◽  
Chloride Channel ◽  
Cell Membranes ◽  
Toxic Effects ◽  
Parasitic Diseases ◽  
Mosquito Larvae ◽  
Channel Activation ◽  
Synthetic Drug

The effects of ivermectin, a semi-synthetic drug widely used for treatment of livestock parasitic diseases, were observed on Culex quinquefasciatus larvae. Toxic effects and mortality evaluation were carried out after 5, 15, 30 and 60 minutes of exposure to 1, 5 or 10 ppm of ivermectin solutions. Observations were made 24 and 48 hours after the beginning of the experiment, and loss of mobility, progressive paralysis and high mortality of larvae were recorded. The observed effects of ivermectin on the mosquito larvae is probably correlated with chloride channel activation on cell membranes.

Synergism between permethrin and propoxur against Culex quinquefasciatus mosquito larvae

2003 ◽  
Vol 17 (2) ◽  
pp. 158-164 ◽  
Author(s):  
V. Corbel ◽  
F. Chandre ◽  
F. Darriet ◽  
F. Lardeux ◽  
J-M. Hougard
Keyword(s):  
Culex Quinquefasciatus ◽  
Mosquito Larvae

scholarly journals The effect of coexistence between larvae of Anopheles gambiae and Culex quinquefasciatus on larvicidal efficacy of Bacillus thuringiensis var. israelensis

2021 ◽  
Vol 3 (1) ◽  
pp. 77-85
Author(s):  
Yahya A. Derua ◽  
Eliningaya J. Kweka ◽  
William N. Kisinza ◽  
Guiyun Yan ◽  
Andrew K. Githeko ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Anopheles Gambiae ◽  
Culex Quinquefasciatus ◽  
Significant Variation ◽  
General Trend ◽  
Sensu Stricto ◽  
Probit Analysis ◽  
Mosquito Larvae ◽  
Breeding Habitats ◽  
Larval Bioassay

Background: The efficacy of Bacillus thuringiensis var. israelensis (Bti) is affected by several factors including the species of the mosquito. Mosquito larvae of different species are found to coexist in larval breeding habitats. This study evaluated whether the coexistence between Anopheles gambiae and Culex quinquefasciatus affect the larvicidal activity of Bti. Methods: Two parallel larval bioassay experiments were conducted to test A. gambiae sensu stricto (s.s) and C. quinquefasciatus larvae susceptibility to Bti. They were followed by three parallel bioassays in which A. gambiae s.s and C. quinquefasciatus larvae were mixed in different proportions such that the earlier species contributed three quarters, half and a quarter of the larvae in each testing cup respectively. In each bioassay, six Bti concentrations were tested in four replicates and repeated on three different days. Larvae mortality was scored 24 hours after application of Bti and subjected to Probit analysis. Results: C. quinquefasciatus was significantly more susceptible to Bti than A. gambiae s.s at both lethal concentration values (LC50 and LC95). In coexisting scenario, LC50 of Bti was significantly lower when the proportion of C. quinquefasciatus exceeded 50%. No significant variation in susceptibility to Bti was observed at LC95 in any proportion of coexistence between the two species. Conclusion: The findings show that larvae of C. quinquefasciatus were significantly more susceptible to Bti than those of A. gambiae s.s. Moreover, when larvae of the two species coexisted, there was a general trend of increase in sensitivity to Bti with higher proportion of C. quinquefasciatus. Although this increase in sensitivity of coexisting larvae to Bti is worth noting, our findings suggest that it will not impact larval control where A. gambiae s.s and C. quinquefasciatus coexist.

scholarly journals Larvicidal efficacy of the crude leaf extracts of Eucalyptus camaldulensis Dehn (Myrtales: Myrtaceae) against the mosquito larvae of Culex quinquefasciatus Say (Diptera: Culicidae)

2018 ◽  
Vol 27 (2) ◽  
pp. 135-144
Author(s):  
Humayun Reza Khan ◽  
Nigar Sultana ◽  
Prova Sharmin
Keyword(s):  
Culex Quinquefasciatus ◽  
Leaf Extract ◽  
Mosquito Species ◽  
Eucalyptus Camaldulensis ◽  
Control Treatment ◽  
High Dose ◽  
Mosquito Larvae ◽  
The Sun ◽  
Leaf Extracts ◽  
Water Based

Eucalyptus camaldulensis was assayed to evaluate the larvicidal efficacy of its leaf extracts against the 3rd instar larvae of Culex quinquefasciatus at five dose concentrations (viz. 0.25, 0.50, 0.75, 1.0, 1.25, 1.5, 2.0, 2.5 and 3.0) in five solvents (viz. chloroform, ethanol, di-chloromethane, acetone and water) based extracts after 24 hrs exposure. Among all the extracts the shade dried chloroform based leaf extracts showed the highest larvicidal efficacy (viz. 42.67, 56.67, 68.0, 92.67 and 100%) at low dose concentrations of 0.25, 0.50, 0.75, 1.0 and 1.25, respectively while the sun dried water based leaf extracts showed the lowest larvicidal efficacy (viz. 21.33, 30.67, 48.67, 58.0 and 74.0%) at high dose concentrations of 1.0, 1.5, 2.0, 2.5 and 3.0, respectively among the ten different experimental conditions. The relative potency of ten types of crude leaf extracts of E. camaldulensis against the mosquito larvae are shown as follows in decreasing order on the basis of LC50 value : Shade dried chloroform based leaf extract (0.356 mg/ml) > sun dried chloroform based leaf extract (0.400 mg/ml) > shade dried di-chloromethane based leaf extract (0.411 mg/ml) > sun dried dichloromethane based leaf extract (0.579 mg/ml) > shade dried ethanol based leaf extract (0.736 mg/ml) > sun dried ethanol based leaf extract (0.817 mg/ml) > shade dried acetone based leaf extract (1.000 mg/ml) > sun dried acetone based leaf extract (1.251 mg/ml) > shade dried water based leaf extract (1.807 mg/ml) > Sun dried water based leaf extract (2.020 mg/ml).The effectiveness of the shade dried leaf extracts was shown higher than the sun dried leaf extracts under comparable condition. No mortality was observed in control treatment. The study revealed that these leaf extracts have the potency to consider as an effective larvicidal agent. It is an alternative source for developing a novel larvicide for controlling the mosquito species. Dhaka Univ. J. Biol. Sci. 27(2): 135-144, 2018 (July)

scholarly journals Mosquitocidal activities of Chenopodium botrys whole plant n-hexane extract against Culex quinquefasciatus

2023 ◽  
Vol 83 ◽  
Author(s):  
I. Ilahi ◽  
A. M. Yousafzai ◽  
M. Attaullah ◽  
T. U. Haq ◽  
A. Rahim ◽  
...  
Keyword(s):  
Culex Quinquefasciatus ◽  
Activity Index ◽  
Adult Emergence ◽  
Retention Factor ◽  
Hexane Extract ◽  
Oviposition Deterrent ◽  
Adulticidal Activity ◽  
Whole Plant ◽  
Control And Prevention ◽  
Inhibitory Activities

Abstract This research aimed to investigate various mosquitocidal activities of Chenopodium botrys whole- plant n-hexane extract against Culex quinquefasciatus. The extract showed remarkable larvicidal, pupicidal, adulticidal, oviposition deterrent and adult emergence inhibitory activities against Cx. quinquefasciatus. During the larvicidal and pupicidal activities, the 24-hour lethal concentration (LC50) of extract against 2nd instar larvae, 4th instar larvae and pupae were 324.6, 495.6 and 950.8 ppm, respectively. During the CDC (Centers for Disease Control and Prevention) bottle bioassay for adulticidal activity, the median knockdown times (KDT50) at 1.25% concentration was 123.4 minutes. During the filter paper impregnation bioassay for adulticidal activity, the KDT50 value at 0.138 mg/cm2 concentration was 48.6 minutes. The extract was fractionated into 14 fractions through silica gel column chromatography which were then combined into six fractions on the basis of similar retention factor (Rf) value. These fractions were screened for adulticidal activity by applying CDC bottle bioassay. The fraction obtained through 60:40 to 50:50% n-hexanes-chloroform mobile phase with 0.5 Rf value showed 100% adulticidal activity at 0.2% concentration. During oviposition deterrent activity, the highest concentration (1000 ppm) showed 71.3 ± 4.4% effective repellence and 0.6 ± 0.1 oviposition activity index. During adult emergence inhibition activity, the median emergence inhibition (EI50) value was 312.3 ppm. From the outcome of the present investigation, it is concluded that the n-hexane extract of C. botrys whole- plant possesses strong larvicidal, pupicidal, adulticidal, oviposition deterrent and adult emergence inhibitory activities against Cx. quinquefasciatus.

scholarly journals Efektivitas Biolarvasida Ekstrak Fraksi Polar Daun Citrus hystrix dan Citrus aurantifolia terhadap Culex quinquefasciatus

2018 ◽  
Vol 12 (1) ◽  
pp. 33-38
Author(s):  
Arif Nur Muhammad Ansori ◽  
Hebert Adrianto ◽  
Hamidah Hamidah
Keyword(s):  
Vector Control ◽  
Larvicidal Activity ◽  
Experimental Research ◽  
Culex Quinquefasciatus ◽  
Polar Fraction ◽  
Mosquito Larvae ◽  
Citrus Aurantifolia ◽  
Development Of Resistance ◽  
Randomized Design ◽  
Completely Randomized Design

Abstract The development of resistance to chemical insecticides against mosquitoes has beenconsidered as a setback in vector control. This study was aimed to identify LethalConcentration 90% (LC90) of polar fraction extract from  Citrus hystrix and Citrusaurantifolia leaves as biolarvicide against mosquito larvae after 24 hours of exposure.This study was an experimental research based on a Completely Randomized Design(CRD). The polar fraction extract of C. hystrix and C. aurantifolia  were tested in concentrations of 0 ppm, 500 ppm, 1375 ppm, 2250 ppm, 3125 ppm, and 4000 ppm againstthe 3rd instar larvae of  Culex quinquefasciatus. Each treatment was done in five independent replications. The numbers of deceased mosquito larvae were determinedafter 24 hours of treatment and analyzed by probit. The results showed that the polarfraction extract of  C. hystrix and C. aurantifolia  have bio-larvicidal activity against the 3rdinstar larvae of Cx. quinquefasciatus at LC90 of 1,653 ppm and 2,797 ppm, respectively. In conclusion, the polar fraction extract of C. hystrix leaf is more toxic than C. aurantifolialeaf's against  Cx. quinquefasciatus larvae. Abstrak Perkembangan resistensi terhadap insektisida kimia di antara spesies nyamuk telahdianggap sebagai kemunduran dalam pengendalian vektor. Penelitian ini bertujuanuntuk mengetahui Lethal Concentration 90% (LC90 ) ekstrak fraksi polar daun  C. hystrix dan C. aurantifolia sebagai biolarvasida terhadap larva nyamuk setelah paparan 24 jam. Penelitian ini adalah penelitian eksperimental dengan Rancangan Acak Lengkap (RAL).Ekstrak fraksi polar daun C. hystrix dan C. aurantifolia  diuji dengan konsentrasi 0 ppm,500 ppm, 1.375 ppm, 2.250 ppm, 3.125 ppm, dan 4.000 ppm terhadap larva nyamuk Cx.quinquefasciatus instar III. Setiap konsentrasi dilakukan replikasi sebanyak lima kali.Jumlah larva nyamuk yang mati dihitung setelah 24 jam. Setelah itu, data dari larvanyamuk yang mati dianalisis menggunakan probit. Hasil penelitian ini mengungkapkanbahwa ekstrak fraksi polar daun C. hystrix dan C. aurantifolia memiliki aktivitas sebagai biolarvasida terhadap larva nyamuk Cx. quinquefasciatus instar III dengan LC 90= 1.653  ppm dan 2.797 ppm, secara berurutan. Kesimpulan dari penelitian ini adalah ekstrakfraksi polar dari daun C. hystrix lebih toksik dibandingkan dengan  C. aurantifoliaterhadap larva nyamuk instar III.  

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