Efficacies of four plant essential oils as larvicide, pupicide and oviposition deterrent agents against dengue fever mosquito, Aedes aegypti Linn.(Diptera: Culicidae)

Objective:To evaluate larvicidal,pupicidal and oviposition deterrent activities of four plant essential oils from Alpinia galanga(L.)Willd rhizome,Anethum graveolens L.(An.graveolens)fruit,Foeniculum vulgare Mill.fruit,and Pimpinella anisum L.fruit against Aedes aegypti(Ae.aegypti).Methods:Four essential oils at 1%,5%and 10%concentrations were assessed for insecticidal activity against larvae and pupae of Ae.aegypti,following the procedure of a dipping method assay.Oviposition deterrent activity of four essential oils was evaluated on gravid female of Ae.aegypti by a dual-choice oviposition bioassay.Results:The results revealed that An.graveolens oil provided the strongest larvicidal activity against Ae.aegypti among four tested plant essential oils with the highest mortality rate of 100%and LC_(50)value of-0.3%.From the pupicidal experiment,An.graveolens also showed the highest toxicity against Ae.aegypti pupae with the highest mortality rate of 100%at 72 h and LC_(50)value of2.9%.In addition,10%An.graveolens had an oviposition deterrent effect against Ae.aegypti with effective repellency of 100%and an oviposition activity index of-1.0.Conclusions:An.graveolens oil has a good potential as a larvicidal,pupicidal and oviposition deterrent agent for controlling Ae.aegypti.

Larvicidal and repellent potential of Moringa oleifera against malarial vector,Anopheles stephensi Liston(Insecta:Diptera:Culicidae)

Objective:To evaluate the larvicidal and pupicidal potential of the methanolic extracts from Moringa oleifera(M.oleifera) plant seeds against malarial vector Anopheles stephensi(A.stephensi) mosquitoes at different concentrations(20,40,60,80 and 100 ppm).Methods:M.oleifera was collected from the area of around Bharathiar University,Coimbatore.The dried plant materials were powdered by an electrical blender.From each sample,100 g of the plant material were extracted with 300 mL of methanol for 8 h in a Soxhlet apparatus.The extracts were evaporated to dryness in rotary vacuum evaporator to yield 122 mg and 110 mg of dark greenish material(residue) from Arcang amara and Ocimum basilicum,respectively.One gram of the each plant residue was dissolved separately in 100 mL of acetone(stock solution) from which different concentrations, i.e.,20,40,60,80 and 100 ppm were prepared.Results:Larvicidal activity of M.oleifera exhibited in the first to fourth instar larvae of the A.stephensi,and the LC_(50) and LC_(90) values were 57.79 ppm and 125.93 ppm for the first instar,63.90 ppm and 133.07 ppm for the second inslar,72.45 ppm and 139.82 ppm for the third instar,78.93 ppm and 143.20 ppm for the fourth instar,respectively. During the pupal stage the methanolic extract of M.oleifera showed that the LC_(50),and LC_(90) values were 67.77 ppm and 141.00 ppm,respectively.Conclusions:The present study indicates that the phytochemicals derived from M.oleifera seeds extracts are effective mosquito vector control agents and the plant extracts may be used for further integrated pest management programs.

Evaluation of aqueous and ethanol extract of bioactive medicinal plant,Cassia didymobotrya(Fresenius)Irwin & Barneby against immature stages of filarial vector,Culex quinquefasciatus Say(Diptera:Culicidae)

Objective:To evaluate aqueous and ethanol extract of Cassia didymobotrya leaves against immature stages of Culex quinquefasciatus.Methods:The mortality rate of immature mosquitoes was tested in wide and narrow range concentration of the plant extract based on WHO standard protocol.The wide range concentration tested in the present study was 10 000,1 000,100,10 and1 mg/L and narrow range concentration was 50,100,150,200 and 250 mg/L.Results:2nd instar larvae exposed to 100 mg/L and above concentration of ethanol extract showed 100%mortality.Remaining stages such as 3rd,4th and pupa,100%mortality was observed at 1 000 mg/L and above concentration after 24 h exposure period.In aqueous extract all the stages 100%mortality was recorded at 1000 mg/L and above concentration.In narrow range concentration 2nd instar larvae 100%mortality was observed at 150 mg/L and above concentration of ethanol extract.The remaining stages 100%mortality was recorded at 250 mg/L.In aqueous extract all the tested immature stages 100%mortality was observed at 250 mg/L concentration after 24 h exposure period.The results clearly indicate that the rale of mortality was based dose of the plant extract and stage of the mosquitoes.Conclusions:From this study it is confirmed and concluded that Cassia didymobotrya is having active principle which is responsible for controlling Culex quinquefasciatus.The isolation of biouctive molecules and development of simple formulation technique is important for large scale implementation.

Larvicidal, pupicidal and oviposition deterrent activities of essential oils from Umbelliferae plants against house fly Musca domestica

To evaluate the toxicity against house fly Musca domestica L.(M. domestica)-larvicidal, pupicidal, and oviposition deterrent activities of essential oils(EOs) from five plants: Anethum graveolens L.(A. graveolens), Centratherum anthelminticum L.(C. anthelminticum), Foeniculum vulgare Mill.(F. vulgare), Pimpinella anisum L.(P. anisum), and Trachyspermum ammi L.(T. ammi) Sprague. Methods: Dipping, topical and dual-choice assays were performed by using each EO at three concentrations(1%, 5% and 10%) as well as cypermethrin(positive control) and ethyl alcohol(negative control) in order to determine their larvicidal, pupicidal and oviposition deterrent activities against M. domestica mortality rate and morphogenic abnormality of larvae and pupae were recorded after 3 and 10 days of incubation. Oviposition deterrent activity was recorded for 5 consecutive days from the beginning of the assay. Results: All EOs at the highest concentration(10%) were highly effective in oviposition deterrent with 100% effective repellency and an oviposition activity index of-1.00. Ten percent of F. vulgare oil exhibited the highest efficacy against the larvae with 89.6% mortality rate at 3 days and an LC50 value of 5.4%. Ten percent of A. graveolens and T. ammi oils showed the highest efficacy against the pupae with 100% mortality and an LC50 value ranging from 1.81%-2.24%. Conclusions: These results indicate that F. vulgare, A. graveolens and T. ammi EOs are effective larvicidal, pupicidal and oviposition deterrent agents against house fly M. domestica.

Mosquito larvicidal and pupicidal activity of Euphorbia hirta Linn.(Family:Euphorbiaceae) and Bacillus sphaericus against Anopheles stephensi Liston.(Diptera:Culicidae)

Objective:To explore the larvicidal and pupicidal activity of Euphorbia hirta（E.hirta） leaf extract and Bacillus sphaericus（B.sphaericus） against the malarial vector.Anopheles siephensi（An. stephensi）.Methods:The larvicidal and pupicidal activity was assayed against An.stephensi at various concentrations ranging from（75-375 ppm） under the laboratory as well as field conditions. The LC50 and LC90 value of the E.hirta leaf extract was determined by probit analysis.Results: The plant extract showed larvicidal effects after 24 h of exposure;however,the highest larval mortality was found in the methanol extract of E.hirta against the first to fourth instars larvae and pupae of values LC50=137.40,172.65,217.81,269.37 and 332.39 ppm;B.sphaericus against the first to fourth instars larvae and pupae of values LC50= 44.29,55.83,68.51,82.19 and 95.55 ppm, respectively.Moreover,combined treatment of values of LC50= 79.13,80.42,86.01,93.00 and 98.12 ppm,respectively.No mortality was observed in the control.Conclusions:These results suggest methanol leaf extracts of E.hirta and B.sphaericus have potential to be used as an ideal ecofriendly approach for the control of the malarial vector.An.stephensi as target species of vector control programs.This study provides the first report on the combined mosquito larvicidal and pupicidal activity of this plant crude extract and bacterial toxin against An.stephensi mosquitoes.

Larvicidal,ovicidal and pupicidal activities of Gliricidia sepium(Jacq.)(Leguminosae) against the malarial vector,Anopheles stephensi Liston(Culicidae:Diptera)

Objective:To investigate the potentiality of mosquitocidal activity of Gliricidia sepium（C.sepium） （Jacq.）（Leguminosae）.Methods:Twenty five early third instar larvae of Anopheles stephensi （An.stephensi） were exposed to various concentrations（50-250 ppm） and the 24 h LC50 values of the G.sepium extract was determined by probit analysis.The ovicidal activity was determined against An.stephensi to various concentrations ranging from 25-100 ppm under laboratory conditions.The eggs hatchabilily was assessed 48 h post treatment.The pupicidal activity was determined against An.stephensi to various concentrations ranging from 25-100 ppm.Mortality of each pupa was recorded after 24 h of exposure to the extract.Results:Results pertaining to the experiment clearly revealed that ethanol extract showed significant larvicidal,ovicidal and pupicidal activity against the An.stephensi.Larvicidal activity of ethanol extracts of G.sepium showed maximum mortality in 250 ppm concentration（96.0±2.4）%.Furthermore,the LC50 was found to be 121.79 and the LC50 value was recorded to be 231.98 ppm.Ovicidal activity of ethanol extract was assessed by assessing the egg hatchabilily.Highest concentration of both solvent extracts exhibited 100%ovicidal activity.Similarly,pupae exposed to different concentratioiLs of ethanol extract were found dead with 58.10%adult emergence when it was treated with 25 ppm concentration.Similarly,18.36（n=30;61.20%）;21.28（70.93） and 27.33（91.10） pupal mortality was recorded from the experimental pupae treated with 50,75 and 100 ppm concentration of extracts. Three fractions have been tested for their larvicidal activity of which the Fraction 3 showed the LC50 and LC90 values of 23.23 and 40.39 ppm.With regard to the ovicidal effect fraction 3 showed highest ovicidal activities than the other two fractions.Furthermore,there were no hatchabilily was recorded above 50 ppm（100%egg mortality） in the experimental group.Statistically significant pupicidal activity was recorded from 75 ppm concentration.Conclusions:From the results it can be concluded the crude extract of G.sepium is an excellent potential for controlling An.stephensi mosquito.It is apparent that,iraction 3 possess a novel and active principle which could be responsible for those biological activities.

Efficacy of larvicidal and pupicidal activity of Catharanthus roseus aqueous and solvent extracts against Anopheles stephensi Liston and Culex quinquefasciatus Say (Diptera: Culicidae)

Objective: To investigate the larvicidal and pupicidal activities of aqueous, ethyl acetate and methanol extracts of Catharanthus roseus ( C. roseus ) against malaria and filariasis vectors. Methods: The larvicidal and pupicidal activities of C. roseus leaf extracts were tested against the fourth instar larvae and pupae of Anopheles stephensi ( An. stephensi ) and Culex quinquefasciatus ( Cx. quinquefasciatus ). The mortality was observed after 24 and 48 h post the treatment. The data were subjected to probit analysis to determine the lethal concentrations (LC 50 and LC 90 ) at which 50% and 90% of the treated larvae or pupae of the tested species were killed. Results: The larval and pupal mortality were observed after 24 and 48 h of exposure of aqueous, ethyl acetate and methanol extracts of C. roseus ; no mortality was observed in the control group. The LC 50 values against the fourth-instar larvae of An. stephensi were 68.62 and 72.04 mg/mL for the aqueous extract, 82.47 mg/mL for the ethyl acetate extract, and 78.80 and 86.64 mg/mL for the methanol extract, while the aqueous, ethyl acetate and methanol extracts had LC 50 values of 85.21, 76.84 and 94.20 mg/mL against the fourth-instar larvae of Cx. quinquefasciatus . The aqueous, ethyl acetate and methanol extracts had LC 50 values of 118.08, 182.47 and 143.80 mg/mL against the pupae of An. stephensi and 146.20, 226.84 and 156.62 mg/mL against the pupae of Cx. quinquefasciatus , respectively. Conclusions: The aqueous and methanol extracts of C. roseus leaves had an excellent potential to control the malarial vector An. stephensi and filariasis vector Cx. quinquefasciatus .

Evaluation of water and ethanol extracts of Schinus molle Linn.against immature Culex quinquefasciatus Say(Diptera:Culicidae)

Objective:To evaluate larvicidal and pupicidal activities of aqueous and ethanol extract of different parts of Schinus molle against filarial vector,Culex quinquefasciatus(Cx.quinquefasciatus)in the laboratory.Methods:The mortality rate of third,fourth instar larvae and pupal stages were tested at 20,40,60,80 and 100 mg/L of plant extract using WHO standard protocol with modifications.The mortality rate was recorded continuously for 24,48 and 72 h post exposure period and percentage mortality was calculated.Results:Maximum percentage mortality of third instar was 83.3%in ethanol extract of mature fruit at 100 mg/L after 24 h exposure period.After 48 h exposure period,93.3%percentage mortality was recorded in ethanol extract of immature fruit at 100 mg/L.After 72 h exposure period,100%mortality was recorded in water extract of leaf at 100 mg/L.In fourth instar larvae,maximum percentage mortality of 63.3%was recorded in water extract of mature fruit and ethanol extract of immature and mature fruit at 100 mg/L after 24 h exposure period.After 48 h exposure period 86.6%mortality was recorded in ethanol extract of mature fruit at 100 mg/L.After 72 h exposure period,93.3%mortality was recorded in ethanol extract of mature fruit at 100 mg/L.In general immature Cx.quinquefasciatus,percentage mortality was increased with increase in exposure time and concentration of the plant extracts tested.Conclusions:From this laboratory study,Schinus molle plant parts were proved to have larvicidal and pupicidal activity against immature Cx.quinquefasciatus.

Evaluation of immature mosquitocidal properties of Xanthium strumarium Linn.plant extracts against Culex mosquitoes(Diptera:Culicidae)

Objective:To evaluate immature mosquitocidal properties of Xanthium strumarium plant extracts against Culex mosquitoes at Entomology Laboratory,Maraki Campus,University of Gondar.Methods:The immature mosquitocidal activity of plant extracts was tested by following World Health Organization recommended protocol.Acetone,methanol and water extracts were prepared at 50,100,150,200 and 250 mg/L concentrations and tested against third and fourth instar larvae and pupae of Culex mosquitoes.The mortality rate of immature mosquitoes was recorded after 24,48 and 72 h exposure period continuously.Results:Third instar larvae after 24 h exposure period,maximum mortality of 77.80%was recorded at 250 mg/L concentration of acetone extract.After 48 h and 72 h exposure period,maximum mortality of 88.90%was recorded in acetone extract in all the tested concentration.The maximum mortality of fourth instar larvae was 88.90%in acetone extract at 200 and 250 mg/L concentrations.Pupal mortality was also greater in acetone extract.The percentage of mortality in all the stage of mosquitoes was higher in acetone extract followed by methanol and water extract.Conclusions:The percentage of mortality is associated with concentration of the extracts tested and exposure period.This laboratory study confirmed immature mosquitocidal activity of Xanthium strumarium leaf extracts against Culex mosquitoes.The aqueous leaf extract can be used by applying on small man-made breeding places to prevent adult emergence.

Mosquitocidal properties of Oxystelma esculentum(Asclepiadaceae)-Indian medicinal plant tested against Ades aegypti(Linn.)(Diptera:Culicidae)

Objective:To evaluate the mosquitocidal activities of various solvent extract of Oxystelma esculentum(O.esculentum)against the medically important dengue vector mosquito,Aedes aegypti(Ae.aegypti)L.Methods:A total of 25 early third instar larvae of Ae.aegypti were exposed to various concentrations(60-300 mg/L)and were assayed in the laboratory by using the protocol of World Health Organization,2005;the 24 h LC_(50) values of the O.esculentum leaf extract was determined by probit analysis.The ovicidal activity was determined against the freshly laid eggs of Ae.aegypti to various concentrations ranging from 50-300 mg/L under laboratory conditions.The pupicidal activity was determined against pupae of Ae.aegypti to various concentrations ranging from 70-280 mg/L after 24 h of exposure to the concern extract.The repellent efficacy was determined against adult female mosquito species at 1.0,2.0 and 3.0 mg/cm^(2) under laboratory conditions.Results:The LC_(50) value of methanol extract of O.esculentum against 3rd instar larvae of Ae.aegypti was 125.82 mg/L.The same extract showed 100%egg mortality at 250 mg/L and also pupicidal activity observed against the pupae of Ae.aegypti at 280 mg/L.Conclusions:The present results suggest that the O.esculentum leaf extracts provided an excellent,potential phytopesticide for controlling Ae.aegypti mosquito.

Mosquitocidal activity of indigenenous plants of Western Ghats,Achras sapota Linn.(Sapotaceae)and Cassia auriculata L.(Fabaceae)against a common malarial vector,Anopheles stephensi Liston(Culicidae:Diptera)

Objective:To evaluate the mosquito larvicidal,ovicidal,pupicidal and repellent activities of hexane,diethyl ether,dichloromethane,acetone and methanol extracts of Indian medicinal plants,Achras sapota(A.sapota)and Cassia auriculata(C.auriculata)at different concentrations against Anopheles stephensi(An.stephensi),a malarial vector.Methods:Twenty five early third instar larvae of An.stephensi were exposed to various concentrations(30-210 mg/L)of plants extracts and were assayed in the laboratory by using the protocol of WHO 2005;then after 24 h LC_(50) values of the A.sapota and C.auriculata leaf extract was determined by probit analysis.The ovicidal activity was tested with the extracts ranging from 50-350 mg/L.The pupicidal activity was recorded after 24 h of exposure to the extract.The repellent efficacy was determined against mosquito species at two different concentrations 1.5 and 3.0 mg/cm^(2) under laboratory conditions.Results:Among the five different extracts tested against the An.stephensi,methanol extract of A.sapota proved to be an more effective solvent extract in almost all the parameters studied than C.auriculata.Conclusions:It is inferred that the leaf extract of A.sapota and C.auriculata could be used in vector control programme.