Anopheles Stephensi Larvae Research Articles

Identification of the Temperature Induced Larvicidal Efficacy of Agave angustifolia against Aedes, Culex, and Anopheles Larvae.

Synthetic insecticides are generally employed to control the mosquito population. However, their injudicious over usage and non-biodegradability are associated with many adverse effects on the environment and mosquitoes. The application of environment-friendly mosquitocidals might be an alternate to overcome these issues. In this study, we found that organic or aqueous extracts of Agave angustifolia leaves exhibited a strong larvicidal activity (LD50 28.27 μg/ml) against Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi larvae within a short exposure of 12 h. The larvicidal activity of A. angustifolia is inherited and independent of the plants vegetative growth. Interestingly, the plant larvicidal activity was observed exclusively during the summer season (April–August, when outside temperature is between 30 and 50°C) and it was significantly reduced during winter season (December–February, when the outside temperature falls to ~4°C or lower). Thus, we hypothesized that the larvicidal components of A. angustifolia might be induced by the manipulation of environmental temperature and should be resistant to the hot conditions. We found that the larvicidal activity of A. angustifolia was induced when plants were maintained at 37°C in a semi-natural environment against the controls that were growing outside in cold weather. Pre-incubation of A. angustifolia extract at 100°C for 1 h killed 60% larvae in 12 h, which gradually increased to 100% mortality after 24 h. In addition, the dry powder formulation of A. angustifolia, also displayed a strong larvicidal activity after a long shelf life. Together, these findings revealed that A. angustifolia is an excellent source of temperature induced bioactive metabolites that may assist the preparedness for vector control programs competently.

Multipurpose effectiveness of Couroupita guianensis-synthesized gold nanoparticles: high antiplasmodial potential, field efficacy against malaria vectors and synergy with Aplocheilus lineatus predators.

Mosquito-borne diseases represent a deadly threat for millions of people worldwide. According to recent estimates, about 3.2 billion people, almost half of the world's population, are at risk of malaria. Malaria control is particularly challenging due to a growing number of chloroquine-resistant Plasmodium and pesticide-resistant Anopheles vectors. Newer and safer control tools are required. In this research, gold nanoparticles (AuNPs) were biosynthesized using a cheap flower extract of Couroupita guianensis as reducing and stabilizing agent. The biofabrication of AuNP was confirmed by UV-vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), zeta potential, and particle size analysis. AuNP showed different shapes including spheres, ovals, and triangles. AuNPs were crystalline in nature with face-centered cubic geometry; mean size was 29.2-43.8nm. In laboratory conditions, AuNPs were toxic against Anopheles stephensi larvae, pupae, and adults. LC50 was 17.36ppm (larva I), 19.79ppm (larva II), 21.69ppm (larva III), 24.57ppm (larva IV), 28.78ppm (pupa), and 11.23ppm (adult). In the field, a single treatment with C. guianensis flower extract and AuNP (10 × LC50) led to complete larval mortality after 72h. In standard laboratory conditions, the predation efficiency of golden wonder killifish, Aplocheilus lineatus, against A. stephensi IV instar larvae was 56.38%, while in an aquatic environment treated with sub-lethal doses of the flower extract or AuNP, predation efficiency was boosted to 83.98 and 98.04%, respectively. Lastly, the antiplasmodial activity of C. guianensis flower extract and AuNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. IC50 of C. guianensis flower extract was 43.21μg/ml (CQ-s) and 51.16μg/ml (CQ-r). AuNP IC50 was 69.47μg/ml (CQ-s) and 76.33μg/ml (CQ-r). Overall, our results showed the multipurpose effectiveness of C. guianensis-synthesized AuNPs, since they may be proposed as newer and safer tools in the fight against CQ-r strains of P. falciparum and for field control of malaria vectors, in synergy with wonder killifish predators.

Laboratory Bioassay of <i>Chilodonella uncinata</i>, an Entomopathogenic Protozoan, against Mosquito Larvae

Background & objectives Use of microbial control agents provides alternative method for adequate insect management. We evaluated laboratory bioassay of Chilodonella uncinata , a natural protozoan parasite of mosquito larvae. Methods Two formulations and four strains: North India (Monsoon and Pre-monsoon) strain, South India strain, updated strain of Chilodonella uncinata were tested against Anopheles stephensi , Culex quinquefasciatus and Aedes aegypti larvae at four institutes. Results & Interpretation Delayed development was noted in mosquito larvae exposed to Ch. uncinata formulation that produced better effect in all larval species. Efficacy of this biolarvicide is not dose dependant as least dose produced maximum mortality with minimum post exposure. An. stephensi larvae were most sensitive followed by Cx. quinquefasciatus and Ae. aegypti which required longer post exposure. Of the four strains, updated strain was most effective and stable; south India strain had rapid killing effect; Pre-monsoon strain was more effective than Monsoon strain as the later required 20x higher dose (cs/ml) to induce satisfactory mortality in An. stephensi larvae with higher values for LT 50 (4.71) and LT 90 (6.84) as against LT 50 (2.5) and LT 90 (3.57) of former strain. Tea bag formulation is easy to store, transport and treat, was found to have a shelf life of >18 months resulting in satisfactory efficacy against An. stephensi with LT 50 (5.16) and LT 90 (7.69) noted at 0.25 g even after 6 months of storage. These laboratory test data suggest that a lower dose of this protozoan formulation can be used as a potential biolarvide to control mosquito larvae as an alternative to chemical insecticides under integrated vector management.

Fern-synthesized nanoparticles in the fight against malaria: LC/MS analysis of Pteridium aquilinum leaf extract and biosynthesis of silver nanoparticles with high mosquitocidal and antiplasmodial activity.

Malaria remains a major public health problem due to the emergence and spread of Plasmodium falciparum strains resistant to chloroquine. There is an urgent need to investigate new and effective sources of antimalarial drugs. This research proposed a novel method of fern-mediated synthesis of silver nanoparticles (AgNP) using a cheap plant extract of Pteridium aquilinum, acting as a reducing and capping agent. AgNP were characterized by UV-vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Phytochemical analysis of P. aquilinum leaf extract revealed the presence of phenols, alkaloids, tannins, flavonoids, proteins, carbohydrates, saponins, glycosides, steroids, and triterpenoids. LC/MS analysis identified at least 19 compounds, namely pterosin, hydroquinone, hydroxy-acetophenone, hydroxy-cinnamic acid, 5, 7-dihydroxy-4-methyl coumarin, trans-cinnamic acid, apiole, quercetin 3-glucoside, hydroxy-L-proline, hypaphorine, khellol glucoside, umbelliferose, violaxanthin, ergotamine tartrate, palmatine chloride, deacylgymnemic acid, methyl laurate, and palmitoyl acetate. In DPPH scavenging assays, the IC50 value of the P. aquilinum leaf extract was 10.04 μg/ml, while IC50 of BHT and rutin were 7.93 and 6.35 μg/ml. In mosquitocidal assays, LC50 of P. aquilinum leaf extract against Anopheles stephensi larvae and pupae were 220.44 ppm (larva I), 254.12 ppm (II), 302.32 ppm (III), 395.12 ppm (IV), and 502.20 ppm (pupa). LC50 of P. aquilinum-synthesized AgNP were 7.48 ppm (I), 10.68 ppm (II), 13.77 ppm (III), 18.45 ppm (IV), and 31.51 ppm (pupa). In the field, the application of P. aquilinum extract and AgNP (10 × LC50) led to 100 % larval reduction after 72 h. Both the P. aquilinum extract and AgNP reduced longevity and fecundity of An. stephensi adults. Smoke toxicity experiments conducted against An. stephensi adults showed that P. aquilinum leaf-, stem-, and root-based coils evoked mortality rates comparable to the permethrin-based positive control (57, 50, 41, and 49 %, respectively). Furthermore, the antiplasmodial activity of P. aquilinum leaf extract and green-synthesized AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of P. falciparum. IC50 of P. aquilinum were 62.04 μg/ml (CQ-s) and 71.16 μg/ml (CQ-r); P. aquilinum-synthesized AgNP achieved IC50 of 78.12 μg/ml (CQ-s) and 88.34 μg/ml (CQ-r). Overall, our results highlighted that fern-synthesized AgNP could be candidated as a new tool against chloroquine-resistant P. falciparum and different developmental instars of its primary vector An. stephensi. Further research on nanosynthesis routed by the LC/MS-identified constituents is ongoing.

Effect of Chloroxylon swietenia Dc bark extracts against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi larvae.

Mosquitoes are the vector of more diseases and cause major health problems like malaria, dengue, chikungunya, and lymphatic filariasis. This article deals with the mosquito larvicidal activity of Chloroxylon swietenia Dc bark extracts against late third instar larvae of Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. Methanolic crude extract of Ch. swietenia bark was obtained by soxhlet apparatus and aqueous crude extract by cold percolation method. The range of concentrations of the crude extracts used was 50, 100, 150, 200, and 250ppm. The mortality and lethal concentration (LC50 and LC90) was calculated after a 24-h exposure period. Both the extracts showed trustworthy larvicidal activity. The larvicidal activity of the methanol extract of Ch. swietenia bark was higher than the aqueous extract, and the LC50 and the LC90 values of the methanol extract were found to be 124.70 and 226.26μg/ml (Ae. aegypti), 130.57 and 234.67ppm (Cu. quinquefasciatus), and 137.55 and 246.09ppm (An. stephensi). The LC50 and the LC90 values of the aqueous extract were found to be 133.10 and 238.93ppm (Ae. aegypti), 136.45 and 242.47ppm (Cu. quinquefasciatus), and 139.43 and 248.64ppm (An. stephensi). No mortality was observed in the control. Methanolic crude extract Ch. swietenia bark shows higher activity against An. stephensi than the other two tested larvae and aqueous extract. The results of the present study propose a possible way for further investigations to find out the active molecule responsible for the larvicidal activity of Ch. swietenia bark extracts.

Laboratory evolution of the entomopathogenic fungus Beauveria bassiana against Anopheles stephensi larvae (Diptera: Culicidae)

ObjectiveTo examine Beauveria bassiana (B. bassiana) fungus bioassay against the larval stages of Anopheles stephensi in Iran. MethodsThe fungal suspension by the concentrations of 1×109, 5×108, 108, 5×107 and 1×107 conidia per milliliter have been prepared in different volumes (2, 4 and 6 mL) and each concentration were added to containers containing 25 Anopheles larva instars 1 and 2. The mortality of the dead larvae with abnormal symptoms was recorded as a result of the fungal infection after 24, 48 and 72 h. ResultsComparison between the mean mortality rate of Anopheles stephensi larva at different concentrations of B. bassiana strain Iran 429C at 2, 4 and 6 mL showed that there was no significant relation of the mean mortality rate of larvae at concentrations of 1×109 and 5×108, and after 48 h resulted in 100% mortality rate of the larvae populations. In addition, there is no significant differences in the amounts of lethal times (LT) (LT50 and LT90) as LT90 values calculated at a concentration of 5×108 and in volumes 2, 4 and 6 mL were 1.46, 1.36 and 1.08 d, respectively. ConclusionsB. bassiana strain Iran 429C in 2 mL of 5×108 concentration or the concentration of a 1×109 mL per 100 mL of water is recommended as the optimal concentration for the control of Anopheles larvae. The development of suitable formulations of entomopathogenic fungi may be a promising prospect in the mosquito control programs.

Screening of the Entomopathogenic Fungi, Metarhizium anisopliae and Beauveri bassiana against Early Larval Instars of Anopheles stephensi (Diptera: Culicidae)

Despite many prevention and control programs, the disease of malaria still remains a major health and economic problem in developing countries due to the unexpected resistance of malaria mosquitoes to chemical insecticides. In this study, the virulence of 10 Iranian isolates of the entomopathogenous fungi Beauveria bassiana and Metarhizium anisoplaie were evaluated against Anopheles stephensi larvae. Different strains were screened by adding aqueous suspension of 108 conidia mL-1 to 100 mL water containing 25 early instars larvae. The results showed that Bb 429C and Bb 796C were the most virulent isolates of B. bassiana causing 100 larval mortality with lethal times of 2.29 and 2.53 days for LT50 and 4.34 and 4.34 days for LT90, respectively. Among M. anisopliae isolates, Ma 1018C was the most efficient isolate. Larval mortality rates caused by Ma 1018C at concentrations of 5×107, 108 and 5×108 conidia mL-1 were not significantly different as respectively they killed 99, 97 and 99 of larva at the fourth day. The lowest lethal times were related to the concentration of 5×107conidia mL-1 and were 0.63 and 1.93 days for LT50 and LT90, respectively. Entomopathogenic fungi could be promising prospects and safe alternatives in integrated mosquitoes control programs. © 2014 Academic Journals Inc.

Cassia occidentalis L. (a new source of rotenoids): its in vitro regulation by feeding precursors and larvicidal efficacy

Rotenoids are group of ketonic compounds having chromno chromanone ring structure. In the present study Rotenoids were isolated from various plant parts and callus cultures of Cassia occidentalis L., (Fabaceae), and identified using TLC, gas–liquid chromatography and other spectral techniques comparable to that of the standard rotenoids. The recovery of rotenoids was found to be maximum in the roots and minimum in stem. The isolated compounds were found to effective against Anopheles stephensi larvae with lethal concentration (LC50 and LC 90) as 110.73 and 206.79 ppm, respectively. Precursors were used to enhance the rotenoid production in vitro. Treatment dose of 0.05 mM of both Phenylalanine and Methionine increased the production 1.18 times than the control.

Relative toxicity of different combinations of temephos and fenthion withSolanum xanthocarpumextract against anopheline larvae

The relative toxicity of different concentrations of temephos and fenthion with petroleum ether root extract of Solanum xanthocarpum (Schrader) at 1 : 1, 1 : 2 and 1 : 4 ratios was evaluated against Anopheles stephensi (Liston) larvae. All combinations exhibited antagonism at concentrations lower than LC50 values and synergism at concentrations higher than their LC90 values. A 1 : 1 product ratio was the most effective.

Laboratory testing of larvivorous fish Japanese medaka (Oryzias latipes) predation ability to copper-treated Anopheles stephensi larvae: An alternative method for vector control under low concentration of copper

Laboratory testing of larvivorous fish Japanese medaka (Oryzias latipes) predation ability to copper-treated Anopheles stephensi larvae: An alternative method for vector control under low concentration of copper

Distinct biological effects of golgicide a derivatives on larval and adult mosquitoes

A collection of Golgicide A (GCA) analogs has been synthesized and evaluated in larval and adult mosquito assays. Commercially available GCA is a mixture of four compounds. One enantiomer (GCA-2) of the major diastereomer in this mixture was shown to be responsible for the unique activity of GCA. Structure–activity studies (SAR) of the GCA architecture suggested that the pyridine ring was most easily manipulated without loss or gain in new activity. Eighteen GCA analogs were synthesized of which five displayed distinct behavior between larval and adult mosquitos, resulting in complete mortality of both Aedes aegypti and Anopheles stephensi larvae. Two analogs from the collection were shown to be distinct from the rest in displaying high selectivity and efficiency in killing An. stephensi larvae.

The effect of food concentration and population density of mosquito larvae (Anopheles stephensi, Diptera, Culicidae) on their feeding behavior

The influence of food concentration and population density on the feeding behavior of Anopheles stephensi (Diptera, Culicidae) larvae has been shown experimentally. Lack of food resulted in larvae switching from sweeping the surface film to scraping the substrate off the bottom. The effect of the larval population density was more complex and depended on the food concentration. As a result, the ratio between the larvae keeping to the surface and to the bottom of the vessel was determined by interactions which led to their redistribution between the two trophic niches: the surface film and the bottom substrate. The traits observed ensure plasticity in the use of trophic resources within a water body.

Entomopathogenic fungus generated Nanoparticles for enhancement of efficacy in Culex quinquefasciatus and Anopheles stephensi

ObjectiveTo evaluate to efficacy of silver and gold generated larvicide with the help of entomopathogenic fungus Chrysosporium tropicum against the Culex quinquefasciatus and Anopheles stephensi larvae. MethodsThe silver and gold nanoparticles were quantified and observed by the Micro-scan reader and X-ray diffraction technique. The micrographs of silver and gold nanoparticles were obtained by the Transmission electron microscope and Scanning electron microscope. The larvicidal efficacy was then performed at six different log concentrations by the probit analysis. ResultsThe characterization study confirmed the spherical shaped and sized (20–50 and 2–15 nm) of silver and gold nanoparticles. The all larval stages of Cx. quinquefasciatus were found more susceptible to the synthesized silver nanoparticles. Whereas, the larvae of An. stephensi were found more susceptible to larvicide synthesized with gold nanoparticles. ConclusionsThe results suggested that the silver and gold nanoparticles generated by the entomopathogenic fungus C. tropicum is an environmentally safer and greener approach for mosquito control and new possibility in vector control strategy.

Evaluation of larvicidal potential of certain insect pathogenic fungi extracts against Anopheles stephensi and Culex quinquefasciatus

AbstractFungal metabolites are attracting attention as potential microbial insecticides, and they are anticipated to overcome the problems of pesticide resistance and environmental pollution that are associated with the indiscriminate use of conventional synthetic insecticides. The relative bioefficacies of selected fungal pathogens, Aspergillus flavus, A. niger, A. parasiticus, Fusarium sporotrichoides and Penicillium verrucosum were observed against Anopheles stephensi and Culex quinquefasciatus larvae. A. flavus demonstrated the greatest bioefficacy with 50% lethal concentration (LC50) values of 9.54 and 10.98 ppm against Anopheles stephensi and Culex quinquefasciatus larvae, respectively, after 24‐h exposure. The bioefficacy of A. flavus increased in both species with an exposure time of 48 h, with LC50 values of 7.26 and 8.55 ppm, respectively.

Mosquito larvicidal activity of some common spices and vegetable waste on Culex quinquefasciatus and Anopheles stephensi

Objective To investigate the larvicidal activities of crude and chloroform: methanol (1:1 v/v) extracts of some common spices ( Cuminum cyminum, Allium sativum, Zingiber offinale, Curcuma longa) and vegetable waste ( Solanum tuberosum germinated tuber) against Anopheles stephensi and Culex quinquefasciatus mosquito larvae. Methods Larval mortality of above mosquito species were observed after 24, 48 and 72 h of exposure to five concentrations of aqueous extract (0.1%, 0.2%, 0.3%, 0.4% and 0.5%) and four concentrations (25, 50, 75 ppm) of chloroform: methanol (1:1 v/v) extract. The lethal concentration of individual spices or vegetable waste was determined by log-probit analysis (at 95% confidence level) and effect of crude and chloroform: methanol (1:1 v/v) extracts were recorded on non target organisms. Results Relative mortality rate of both larval mosquito species were recorded in the following sequences: Cuminum cyminum > Allium sativum > Zingiber offinale, Curcuma longa > Solanum tuberosum germinated tuber for crude extract, and efficacy of chloroform: methanol (1:1 v/v) extract were as follows: Curcuma longa > Zingiber offinale > Solanum tuberosum germinated tuber > Cuminum cyminum > Allium sativum. Conclusions Crude and chloroform: methanol (1:1 v/v) extract of Cuminum cyminum, Allium sativum, Zingiber offinale, Curcuma longa and Solanum tuberosum germinated tuber can be recommended effectively in mosquito control programmes at very low concentrations. No mortality and other abnormalities were noticed on non target organisms and further studies are needed to investigate the chemical structure of active principal which are responsible for larvicidal activity.

Status of carbohydrate, protein and lipid profile in the mosquito larvae treated with certain phytoextracts

Objective To investigate the impact of the most potent petroleum ether extract of Artemisia annua (A. annua) and Azadirachta indica (Az. indica) on total carbohydrate, lipid and protein level of Anopheles stephensi and Culex quinquefasciatus larvae. Methods Mosquito larvae were exposed to the extracts selected as per standard WHO procedure. Carbohydrate (glucose), total lipid and protein were estimated by the methods as Nelson, Bragdon and Lowry described, respectively. Results The glucose levels were increased to 27.87% and 46.8%, respectively in anopheline larval tissues after treatment with petroleum ether extract of A. annua and methanolic extract of Az. indica. In culicine larvae, glucose levels were reduced to 58.96% and 24.65%, respectively. After treatment with A. annua extract, lipid contents in anopheline and culicine larvae decreased by 28.57% and 25.0%, respectively and increased by 14.29% and 50.00% in the Anopheles and Culex larvae, respectively after treatment with methanolic extract of Az. indica. Total protein levels were reduced to 63.13% and 92.62% in anopheline and to 32.39% and 48.12% in culicine larvae after treatment with A. annua and Az. Indica extracts, respectively. Conclusions Two extracts produce significant alterations in the biochemical profiles of anopheline and culicine larvae. Further, the impacting factors of extracts on carbohydrate, lipid and protein contents of larvae are species and specific extraction. It indicates the disturbed metabolic activity of the larvae.

In vitro isolation and characterization of biolarvicidal compounds from micropropagated plants of Spilanthes acmella

Spilanthes acmella (Family: Asteraceae) commonly known as "toothache plant" is known to possess strong insecticidal and larvicidal properties. Experiments have been conducted to isolate and characterise the biolarvicidal compounds from the flower head extract of micropropagated S. acmella plants employing various tools like FT-IR, TLC, CC, NMR. FT-IR spectroscopy of the crude hexane extract sample revealed the presence of amide (secondary metabolite) as functional group in S. acmella flower heads. The crude extract was separated into 85 fractions (100 ml each) through silica gel column chromatography using hexane-ethyl acetate mobile phase. All fractions were tested for their larvicidal activity against late III/early IV instar Anopheles stephensi larvae and fraction showing maximum bioefficacy against aforesaid larvae was further resolved into three separate bands on Preparative TLC plate, the respective R (f) values being (a) 0.18, (b) 0.23 and (c) 0.27. Based on Proton NMR spectrum of the eluted compounds and their comparison with published results, three different compounds were identified: N-isobutyl-2,6,8-decatrienamide (compound 1), undeca-2E,7Z,9E-trienoic acid isobutylamide (compound 2) from band a and (2E)-N-(2-methylbutyl)-2-undecene-8,10-diynamide (compound 3) from band b. The amount of the compounds obtained were 338 mg (compounds 1 and 2) and 188.4 mg (compound 3), respectively. This is the first report of biolarvicidal compounds isolation and characterisation from micropropagated S. acmella plants.

Synthesis, Spectroscopic Characterization and Structures of Tributyltin(IV) 4-[((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoates. Toxicity Studies on the Second Larval Instar of the Anopheles stephensi Mosquito Larvae

A series of tributyltin(IV) complexes of 4-[((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoates have been investigated by 1H, 13C, 119Sn NMR, IR and 119Sn Mossbauer spectroscopic techniques in combination with elemental analyses. Single crystal X-ray crystallography of Bu3Sn[O2CC6H4{N=C(H)C6H3-2-OH(N=NC6H4CH3-4)}-p] reveals a distorted tetrahedral structure which is further supported by 119Sn Mossbauer data. Toxicity studies of the tributyltin(IV) complexes along with their ligands 4-[((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoic acids on the second larval instar of the Anopheles stephensi mosquito larvae are also reported.

Behavior of Anopheles stephensi, Aedes albopictus and Culex pipiens larvae; differences in behavior organization

Behavior of Anopheles stephensi, Aedes albopictus and Culex pipiens larvae; differences in behavior organization

A20 Behavior of Anopheles stephensi, Aedes albopictus and Culex pipiens larvae ; differences in behavior organization(The 59th Annual Meeting of the Japan Society of Medical Entomology and Zoology)

A20 Behavior of Anopheles stephensi, Aedes albopictus and Culex pipiens larvae ; differences in behavior organization(The 59th Annual Meeting of the Japan Society of Medical Entomology and Zoology)