Insecticidal Activities of Leaf Methanol Extract of Clerodendrum polycephalum Baker against Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus

Aim: In a view to determining the capacity of Clerodendrum polycephalum to control mosquitoes, the methanol extract of the leaf was investigated for insecticidal activities using three species of mosquitoes, Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus. Methodology: The leaves of C. polycephalum were collected, dried and extracted with methanol. Mosquito larvae were exposed to different concentrations for 24/48h. and sublethal concentrations (L25, 50, 75) of the extract to determine larvicidal activity and monitor growth and development respectively. Twenty (20) blood-fed female Aedes aegyti mosquitoes were allowed to lay eggs on treated filter papers for antioviposition bioassay. The crude extract was separated into N-hexane, Dichloromethane, ethyl-acetate, ethanol fractions using Vacuum Liquid Chromatography to determine the active fraction. Results: Results showed that larval mortalities were in the order C. quiquefasciatus>A. gambiae>A. aegypti with effective concentration ranging from 250 – 8000 ppm. Mortalities at 48hr were significantly different (p<0.05) from mortalities at 24h. Of the four fractions obtained, ethanol fraction gave the highest larval mortality of 100% at 2000 ppm. Larval duration for all the three species of mosquitoes exposed to the crude extract varied between 2.25±0.5 and 3.25±0.5 days. As Antioviposition Index increased from 46.4 - 89.9, percent hatching of mosquito eggs deceased from 87.25 – 67.5% with increasing concentration. Conclusion: The extract of C. polycephalum was found to contain insecticidal compounds which are soluble in polar solvent. The plant could be exploited in mosquito control programme.

Download Full-text

Effectiveness of Three Fruit Seed Extracts as Larvicide against Three Major Mosquito Vectors Aedes aegypti Linnaeus, Culex quinquefasciatus Say and Anopheles gambiae Giles (Diptera: Culicidae)

International Journal of TROPICAL DISEASE & Health ◽

10.9734/ijtdh/2020/v41i2330415 ◽

2020 ◽

pp. 16-29

Author(s):

Lame Younoussa ◽

Kary Mallam Oumarou ◽

Theodora Kopa Kowa ◽

Serge Eteme Enama ◽

Gabriel Agbor Agbor ◽

...

Keyword(s):

Aedes Aegypti ◽

Anopheles Gambiae ◽

Culex Quinquefasciatus ◽

Tap Water ◽

Mosquito Species ◽

Mangifera Indica ◽

Larval Mortality ◽

Persea Americana ◽

Plant Seed ◽

Seed Extracts

The CH2Cl2-MeOH (30:70 v/v) extracts of the seeds of Mangifera indica (Mango), Persea americana (Avocado) and Dacryodes edulis (African plum) were evaluated for potential mosquito larvicidal activity against 3rd and 4th instar larvae of Aedes aegypti, Culex quinquefasciatus and Anopheles gambiae. Extracts were diluted with 1 mL of methanol and concentrations ranging from 1000 to 125 mg/L in 4 replicates each, were prepared in the volume of 100 mL in the plastic cups (250 mL). A volume of 1 mL of methanol added to 99 mL of tap water was prepared as negative control and Bi-one (1000 mg/L) constituted a positive control. In each test solution, 25 larvae of each mosquito species were separately transferred and larval mortality was recorded after 24 h post-treatment. As results, the three plant seed extracts applied at 1000 mg/L caused for at least 79% mortality of each mosquito species larvae assessed. The seed extract of P. americana (LC50 of 98.31, 129.24 and 136.26 mg/L, respectively against An. gambiae, Ae. aegypti and Cx. quiquefasciatus larvae) was the most potent followed by D. edulis (LC50 of 176.87 mg/L for An. gambiae, 198.68 mg/L for Ae. aegypti and 201.70 mg/L for Cx. quinquefasciatus) and M. indica (LC50 of 258.98 mg/L for An. gambiae, 297.35 mg/L for Ae. aegypti and 435.45 mg/L for Cx. quinquefasciatus). Globally, all the seed extracts were more toxic against An. gambiae larvae compared to other mosquito species and need further exploration for the development of a new botanical larvicide to reduce mosquito densities.

Download Full-text

Efektivitas Ekstrak Serai Wangi (Cimbopogon nardus L.) sebagai Larvasida Nyamuk Aedes aegypti (The Effectiveness of Citronella Extract (Cymbopogon nardus) as Larvaside of Aedes aegypti)

JURNAL BIOS LOGOS ◽

10.35799/jbl.10.1.2020.26920 ◽

2019 ◽

Vol 10 (1) ◽

pp. 1

Author(s):

Makkiah Makkiah ◽

Cristina L Salaki ◽

Berty Assa

Keyword(s):

Experimental Study ◽

Regression Analysis ◽

Aedes Aegypti ◽

Crude Extract ◽

Larval Stage ◽

Mosquito Control ◽

Larval Mortality ◽

Probit Regression ◽

Extract Concentration ◽

Cymbopogon Nardus

Efektivitas Ekstrak Serai Wangi (Cimbopogon nardus L.) sebagai Larvasida Nyamuk Aedes aegypti (The Effectiveness of Citronella Extract (Cymbopogon nardus) as Larvaside of Aedes aegypti) Makkiah*), Cristina L Salaki **), Berty AssaProgram Studi Entomologi Pascasarjana Universitas Sam RatulangiManado, 95155*Email: [email protected],**Email korespondensi: [email protected] (Article History: Received 20-10-2019; Revised 27-11-2019; Accepted 30-12-2019) Abstrak Pengendalian nyamuk sebagai vektor utama penularan penyakit DBD hanya dapat dilakukkan dengan cara memutuskan rantai penularannya melalui pengendalian nyamuk. Pengendalian nyamuk dapat dilakukan pada tahap larva dengan menggunakan biolarvasida yang terbuat dari bahan alami dan salah satunya adalah dengan menggunakan ekstrak kasar dari tanaman serai wangi (Cymbopogon nardus). Penelitian ini bertujuan untuk menguji efektivitas ekstrak serai wangi sebagai larvasida larva Aedes aegypti instar III dan IV. Penelitian ini adalah penelitian eksperimental menggunakan rancangan acak lengkap. Larva yang digunakan adalah larva instar III dan IV, dengan perlakuan konsentrasi ekstrak serai wangi 20%, 30%, 40%, dan 50% dalam 250 ml air. Pada penelitian ini terdapat kontrol yaitu aquades yang tidak ditambahkan larutan apapun. Pengamatan kematian larva dilakukan pada jam ke 1, 3, 6, 12, 24, dan jam ke 48 dengan replikasi sebanyak 4 kali. Data presentase mortalitas larva digunakan untuk menghitung nilai LC50 dan LT50 dengan menggunakan analisisi Probit. Hasil penelitian menunjukkan ekstrak serai wangi efektif dalam mematikan 50% dari populasi larva uji dengan nilai LC50 pada konsentrasi 36,48%serta waktu yang di butuhkan untuk mematikan 50% populasi larva uji adalah 10,45 jam. Kata kunci : Ekstrak, Cymbopogon nardus, larvasida, Aedes aegypti Abstract Control of mosquitoes as the main vector of transmission of DHF can only be done by breaking the chain of transmission through mosquito control. Mosquito control can be carried out at the larval stage by using biolarvasides made from natural materials, one of which is by using a crude extract from the citronella plant (Cymbopogon nardus). This research is to find out the effectiveness of citronella extract as larvae of Aedes aegypti larvae instar III and IV. This research is a pure experimental study using a complete random design. The larvae used were instar larvae III and IV, with the treatment of citronella extract concentration of 20%, 30%, 40%, and 50% in 250 ml of water. In this study, there was a control i.e. aquades which did not add any solution. Observation of larvae death was done at 1 hour, 2 hours. 4 hours, 12 hours, 24 hours and 28 hours with replication 4 times. Data on larval mortality were used to calculate LC50 and LT 50 values using Probit regression analysis. The results showed that citronella extract was effective in killing 50% of the population of test larvae with LC50 values at a concentration of 36.48% and the time needed to kill 50% of the population of test larvae was 10,450 hours.Key words: Extract, Cymbopogon nardus, larvasida, Aedes aegypti

Download Full-text

Larvicidal and Repellent Properties of Streptomyces sp. VITJS4 Crude Extract against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae)

Polish Journal of Microbiology ◽

10.33073/pjm-2014-045 ◽

2014 ◽

Vol 63 (3) ◽

pp. 341-348 ◽

Cited By ~ 2

Author(s):

S. JEMIMAH NAINE ◽

C. SUBATHRA DEVI

Keyword(s):

Aedes Aegypti ◽

Ethyl Acetate ◽

Culex Quinquefasciatus ◽

Crude Extract ◽

Tamil Nadu ◽

Anopheles Stephensi ◽

Mosquito Control ◽

Repellent Activity ◽

Streptomyces Sp ◽

Crude Extracts

The aim of the present study was to assess the larvicidal and repellent properties of marine Streptomyces sp. VITJS4 crude extracts. The marine soil samples were collected from the Puducherry coast, Tamil Nadu, India. The isolate Streptomyces sp. VITJS4 was taxonomically characterized and identified. The ethyl acetate crude extract tested for larvicidal property showed 100% mortality for all the 3 species after 24 h exposure against the early fourth instar larvae of malarial vector--Anopheles stephensi at 50% and 90% lethal concentration (LC50 = 132.86, LC90 396.14 ppm); dengue vector--Aedes aegypti (LC50 = 112.78, LC90 336.42 ppm) and filariasis vector--Culex quinquefasciatus (LC50 = 156.53, LC90 468.37 ppm). The Streptomyces sp. VITJS4 solvent extracts of hexane, ethyl acetate, benzene, chloroform and methanol were tested for repellent activity against A. stephensi, A. aegypti and C. quinquefasciatus. The ethyl acetate extract showed complete protection for 210 min at 6 mg/cm2 against these mosquito bites. The crude extract was analyzed further for Fourier Transform-infrared spectroscopy (FT-IR) analysis. In addition to the importance of bioactive compounds, the utilization of Streptomyces sp. VITJS4 crude extracts revealed effective larvicidal and repellent activity against the vectors, which perhaps represents a promising tool in the management of mosquito control.

Download Full-text

Efektivitas Ekstrak Serai Wangi (Cimbopogon nardus L.) sebagai Larvasida Nyamuk Aedes aegypti

JURNAL BIOS LOGOS ◽

10.35799/jbl.10.1.2020.27977 ◽

2019 ◽

Vol 10 (1) ◽

pp. 1

Author(s):

Makkiah Makkiah ◽

Christina L Salaki ◽

Berty Assa

Keyword(s):

Experimental Study ◽

Regression Analysis ◽

Aedes Aegypti ◽

Crude Extract ◽

Larval Stage ◽

Mosquito Control ◽

Larval Mortality ◽

Probit Regression ◽

Extract Concentration ◽

Cymbopogon Nardus

Efektivitas Ekstrak Serai Wangi (Cimbopogon nardus L.) sebagai Larvasida Nyamuk Aedes aegypti (The Effectiveness of Citronella Extract (Cymbopogon nardus) as Larvaside of Aedes aegypti) Makkiah*), Christina L Salaki **), Berty AssaProgram Studi Entomologi Pascasarjana Universitas Sam RatulangiManado, 95155*Email: [email protected],**Email korespondensi: [email protected] (Article History: Received 20-10-2019; Revised 27-11-2019; Accepted 30-12-2019) AbstrakPengendalian nyamuk sebagai vektor utama penularan penyakit DBD hanya dapat dilakukan dengan cara memutuskan rantai penularannya melalui pengendalian nyamuk. Pengendalian nyamuk dapat dilakukan pada tahap larva dengan menggunakan biolarvasida yang terbuat dari bahan alami dan salah satunya adalah dengan menggunakan ekstrak kasar dari tanaman serai wangi (Cymbopogon nardus). Penelitian ini bertujuan untuk menguji efektivitas ekstrak serai wangi sebagai larvasida larva Aedes aegypti instar III dan IV. Penelitian ini adalah penelitian eksperimental menggunakan rancangan acak lengkap. Larva yang digunakan adalah larva instar III dan IV, dengan perlakuan konsentrasi ekstrak serai wangi 20%, 30%, 40%, dan 50% dalam 250 ml air. Pada penelitian ini terdapat kontrol yaitu aquades yang tidak ditambahkan larutan apapun. Pengamatan kematian larva dilakukan pada jam ke 1, 3, 6, 12, 24, dan jam ke 48 dengan replikasi sebanyak 4 kali. Data presentase mortalitas larva digunakan untuk menghitung nilai LC50 dan LT50 dengan menggunakan analisisi Probit. Hasil penelitian menunjukkan ekstrak serai wangi efektif dalam mematikan 50% dari populasi larva uji dengan nilai LC50 pada konsentrasi 36,48%serta waktu yang di butuhkan untuk mematikan 50% populasi larva uji adalah 10,45 jam. Kata kunci : Ekstrak, Cymbopogon nardus, larvasida, Aedes aegypti AbstractControl of mosquitoes as the main vector of transmission of DHF can only be done by breaking the chain of transmission through mosquito control. Mosquito control can be carried out at the larval stage by using biolarvasides made from natural materials, one of which is by using a crude extract from the citronella plant (Cymbopogon nardus). This research is to find out the effectiveness of citronella extract as larvae of Aedes aegypti larvae instar III and IV. This research is a pure experimental study using a complete random design. The larvae used were instar larvae III and IV, with the treatment of citronella extract concentration of 20%, 30%, 40%, and 50% in 250 ml of water. In this study, there was a control i.e. aquades which did not add any solution. Observation of larvae death was done at 1 hour, 2 hours. 4 hours, 12 hours, 24 hours and 28 hours with replication 4 times. Data on larval mortality were used to calculate LC50 and LT 50 values using Probit regression analysis. The results showed that citronella extract was effective in killing 50% of the population of test larvae with LC50 values at a concentration of 36.48% and the time needed to kill 50% of the population of test larvae was 10,450 hours.Keywords: Extract, Cymbopogon nardus, larvasida, Aedes aegypti

Download Full-text

Larvicidal potentiality, longevity and fecundity inhibitory activities of Bacillus sphaericus (Bs G3-IV) on vector mosquitoes, Aedes aegypti and Culex quinquefasciatus

Journal of Entomological and Acarological Research ◽

10.4081/jear.2012.e15 ◽

2012 ◽

Vol 44 (3) ◽

pp. 15 ◽

Cited By ~ 2

Author(s):

Arjunan Nareshkumar ◽

Kadarkarai Murugan ◽

Indra Baruah ◽

Pari Madhiyazhagan ◽

Thiyagarajan Nataraj

Keyword(s):

Aedes Aegypti ◽

Culex Quinquefasciatus ◽

Mosquito Control ◽

Larval Mortality ◽

Bacillus Sphaericus ◽

Control Agent ◽

Vector Borne Diseases ◽

Vector Population ◽

Intervention Measures ◽

Vector Borne

Intervention measures to control the transmission of vector-borne diseases include control of the vector population. In mosquito control, synthetic insecticides used against both the larvae (larvicides) and adults (adulticides) create numerous problems, such as environmental pollution, insecticide resistance and toxic hazards to humans. In the present study, a bacterial pesticide, Bacillus sphaericus (Bs G3-IV), was used to control the dengue and filarial vectors, Aedes aegypti and Culex quinquefasciatus. Bacillus sphaericus (Bs G3-IV) was very effective against Aedes aegypti and Culex quinquefasciatus, showing significant larval mortality. Evaluated lethal concentrations (LC50 and LC90) were age-dependent, with early instars requiring a lower concentration compared with later stages of mosquitoes. Culex quinquefasciatus was more susceptible to Bacillus sphaericus (Bs G3-IV) than was Aedes aegypti. Fecundity rate was highly reduced after treatment with different concentrations of Bacillus sphaericus (Bs G3-IV). Larval and pupal longevity both decreased after treatment with Bacillus sphaericus (Bs G3-IV), total number of days was lower in the B. sphaericus treatments compared with the control. Our results show the bacterial pesticide Bacillus sphaericus (Bs G3-IV) to be an effective mosquito control agent that can be used for more integrated pest management programs.

Download Full-text

Comparison of the Effect of Insecticides on Bumble Bees (Bombus impatiens) and Mosquitoes (Aedes aegypti and Culex quinquefasciatus) by Standard Mosquito Research Methods

Journal of Economic Entomology ◽

10.1093/jee/toaa282 ◽

2020 ◽

Author(s):

Bethany L McGregor ◽

Bryan V Giordano ◽

Alfred E Runkel ◽

Herbert N Nigg ◽

H Lee Nigg ◽

...

Keyword(s):

Aedes Aegypti ◽

Culex Quinquefasciatus ◽

Mosquito Control ◽

The United States ◽

Field Trials ◽

Bombus Impatiens ◽

Acute Effects ◽

Nontarget Effects ◽

Native North American ◽

Significant Mortality

Abstract Mosquito control districts in the United States are limited to two main classes of adulticides, pyrethroids and organophosphates, to control mosquitoes. Two adulticides used to control domestic mosquitoes are Fyfanon EW (malathion, organophosphate) and DeltaGard (deltamethrin, pyrethroid). While the effect of these pesticides on European honeybees (Apis mellifera L., Hymenoptera: Apidae) has been investigated, effects on native pollinators need additional research. The purpose of this study was to investigate the acute nontarget effects of these pesticides on Bombus impatiens Cresson (Hymenoptera: Apidae), a native North American bumble bee species, and compare these effects to wild and laboratory strains of mosquitoes (Aedes aegypti (L.) and Culex quinquefasciatus Say, Diptera: Culicidae) through field and laboratory assays. Bombus impatiens was found to be resistant to Fyfanon EW (x̅ = 6.7% mortality at 50-µg malathion per bottle) at levels that caused significant mortality to study mosquitoes (86.2 ≥ x̅ ≥ 100% mortality) in laboratory bottle bioassays. Comparatively, B. impatiens demonstrated greater mortality to DeltaGard (93.3%) at 2.5-µg deltamethrin/bottle than any mosquito colony assayed (14.1 ≥ x̅ ≥ 87.0% mortality). Only DeltaGard was tested in field applications. In the field, we observed acute effects of DeltaGard on mosquitoes and B. impatiens at 25- and 75-m distance from a truck-mounted ultra-low volume fogger, although treatment effects were not significant for B. impatiens. Additional wild-caught nontarget mortality to DeltaGard field trials was also evaluated. This study indicated that common mosquito control adulticides do cause nontarget mortality to B. impatiens but that impacts are variable depending on pesticide and further studies are needed.

Download Full-text

Larvicidal Effectiveness of Azolla pinnata against Aedes aegypti (Diptera: Culicidae) with Its Effects on Larval Morphology and Visualization of Behavioural Response

Journal of Parasitology Research ◽

10.1155/2018/1383186 ◽

2018 ◽

Vol 2018 ◽

pp. 1-5 ◽

Cited By ~ 4

Author(s):

Nor Shaida Husna Zulkrnin ◽

Nurul Nadiah Rozhan ◽

Nur Amanina Zulkfili ◽

Nik Raihan Nik Yusoff ◽

Mohd Sukhairi Mat Rasat ◽

...

Keyword(s):

Aedes Aegypti ◽

Mosquito Control ◽

Larval Mortality ◽

Control Program ◽

Test Method ◽

World Health ◽

Azolla Pinnata ◽

Agricultural Field ◽

Aquatic Fern ◽

Significant Difference

Dengue is vector-borne diseases with 390 million infections per year extending over 120 countries of the world. Aedes aegypti (L.) (Diptera: Culicidae) is a primary vector for dengue viral infections for humans. Current focus on application of natural product against mosquito vectors has been the main priority for research due to its eco-safety. The extensive use of chemical insecticides has led to severe health problems, environmental pollution, toxic hazards to human and nontarget species, and development of insecticide resistance on mosquitoes. Azolla pinnata is an aquatic fern and predominantly used as feed in poultry industry and as fertilizer in agricultural field for enhancing the fertility of rice paddy soil. The present study was conducted to explore the larvicidal efficacy of A. pinnata using fresh and powdered form against late third-stage larvae (6 days, 5 mm in larvae body length) of Ae. aegypti (L.) (Diptera: Culicidae). The larvicidal bioassays were performed using World Health Organization standard larval susceptibility test method for different concentration for powdered and fresh A. pinnata. Powdered A. pinnata concentration used during larvicidal bioassay ranges from 500ppm to 2000ppm; meanwhile, fresh A. pinnata ranges from 500ppm to 9,000,000 ppm. The highest mortality was at 1853 ppm for powdered A. pinnata compared with fresh A. pinnata at 2,521,535 ppm, while the LC50 for both powdered and fresh A. pinnata recorded at 1262 ppm and 1853 ppm, respectively. Finally, the analysis of variance (ANOVA) showed significant difference on Ae. aegypti larval mortality (F=30.439, df=1, p≤0.001) and concentration (F=20.002, df=1, p≤0.001) compared to powdered and fresh A. pinnata at 24-hour bioassay test. In conclusion, the powdered A. pinnata serves as a good larvicidal agent against Ae. aegypti (L.) (Diptera: Culicidae) and this study provided information on the lethal concentration that may have potential for a more eco-friendly Aedes mosquito control program.

Download Full-text

Global spatial assessment of Aedes aegypti and Culex quinquefasciatus: a scenario of Zika virus exposure

Epidemiology and Infection ◽

10.1017/s0950268818003102 ◽

2018 ◽

Vol 147 ◽

Cited By ~ 5

Author(s):

Alberto J. Alaniz ◽

Mario A. Carvajal ◽

Antonella Bacigalupo ◽

Pedro E. Cattan

Keyword(s):

Aedes Aegypti ◽

Culex Quinquefasciatus ◽

Zika Virus ◽

Mosquito Control ◽

Health Planning ◽

Risk Level ◽

Spatially Explicit ◽

World Population ◽

Potential Vector ◽

Risk Zones

AbstractZika virus (ZIKV) is an arbovirus transmitted mainly by Aedes aegypti mosquitoes. Recent scientific evidence on Culex quinquefasciatus has suggested its potential as a vector for ZIKV, which may change the current risk zones. We aimed to quantify the world population potentially exposed to ZIKV in a spatially explicit way, considering the primary vector (A. aegypti) and the potential vector (C. quinquefasciatus). Our model combined species distribution modelling of mosquito species with spatially explicit human population data to estimate ZIKV exposure risk. We estimated the potential global distribution of C. quinquefasciatus and estimated its potential interaction zones with A. aegypti. Then we evaluated the risk zones for ZIKV considering both vectors. Finally, we quantified and compared the people under risk associated with each vector by risk level, country and continent. We found that C. quinquefasciatus had a more temperate distribution until 42° in both hemispheres, while the risk involving A. aegypti is concentrated mainly in tropical latitudes until 35° in both hemispheres. Globally, 4.2 billion people are under risk associated with ZIKV. Around 2.6 billon people are under very high risk associated with C. quinquefasciatus and 1 billion people associated with A. aegypti. Several countries could be exposed to ZIKV, which emphasises the need to clarify the competence of C. quinquefasciatus as a potential vector as soon as possible. The models presented here represent a tool for risk management, public health planning, mosquito control and preventive actions, especially to focus efforts on the most affected areas.

Download Full-text

Ground Applications of Vectobac® WDG with A1 Super-Duty Mist Sprayer® and Micronair® AU5000 Atomizer for Suppression of Aedes aegypti Populations in the Florida Keys

Journal of the American Mosquito Control Association ◽

10.2987/21-7030 ◽

2021 ◽

Vol 37 (4) ◽

pp. 271-279

Author(s):

Heidi L. Murray ◽

Catherine A. Pruszynski ◽

Lawrence J. Hribar

Keyword(s):

Aedes Aegypti ◽

Mosquito Control ◽

Larval Mortality ◽

Florida Keys ◽

Application Rate ◽

Residential Area ◽

Distilled Water ◽

Bacillus Thuringiensis Israelensis ◽

Key West ◽

F1 Generation

ABSTRACT Since 2011, the Florida Keys Mosquito Control District (FKMCD) has used the WALS® application strategy with VectoBac® WDG containing Bacillus thuringiensis israelensis via helicopter in Key West for the control of Aedes aegypti larval populations. In 2018, FKMCD conducted a study to determine the effectiveness of using a trailer-mounted A1 Super Duty Mist Sprayer® (A1 Mist Sprayers) with a Micronair® AU5000 (Micron Group) atomizer to apply VectoBac WDG by ground at the rate of 0.5 lb/acre (0.56 kg/ha). Bioassay cups were placed in a residential area encompassing open, moderate, and heavy cover scenarios between 0 and 300 ft (0–91.44 m) perpendicular to the spray line. An application rate of 0.5 lbs/acre (0.56 kg/ha) was used. Bioassay cups were collected after application and returned to the laboratory where 100 ml of distilled water and 10 F1 generation Ae. aegypti larvae were added. Laval mortality was monitored at 2, 4, and 24 h. Three separate runs were completed during the summer of 2018. Average larval mortality at 24 h was >90%. The field trial demonstrated sufficient efficacy to introduce this method of larviciding into operational use.

Download Full-text

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

Journal of Medical Entomology ◽

10.1093/jme/tjab114 ◽

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.

Download Full-text