Preliminary evaluation of mosquito larvicidal efficacy of plant extracts

Mosquitoes are the most important single group ofinsects in terms of public health importance, whichtransmit a number of diseases, such as malaria, filariasis,dengue, Japanese encephalitis, etc. causing millionsof deaths every year. Repeated use of syntheticinsecticides for mosquito control has disrupted naturalbiological control systems and led to resurgencesin mosquito populations. It has also resulted in thedevelopment of resistance1, undesirable effects onnon-target organisms and fostered environmental andhuman health concern2, which initiated a search foralternative control measures. Plants are considered asa rich source of bioactive chemicals3 and they may bean alternative source of mosquito control agents.Natural products of plant origin with insecticidalproperties have been tried in the recent past for controlof variety of insect pests and vectors. Essentialoils of leaf and bark of Cryptomeria japonica demonstratedhigh larvicidal activity against Aedesaegypti (Diptera: Culicidae) larvae4. Insecticidalactivity of plant essential oils has been well-describedby Isman5. Azadiractin, the active ingredient of neemhas long been recognised for its mosquito larvicidalcapability. The extracts of Murraya koenigii, Coriandrumsativam, Ferula asafetida and Trigonella foenumgraceum were found to be effective and showedencouraging results against Ae. aegypti6 and Culex(Diptera: Culicidae) mosquito larvae7. It is also reportedthat many compounds with insecticidal potentialhave been isolated from the genus Piper—Pipercide,isolated from Piper negrum (black piper) hasbeen found to be just as active against adjuki beanweevils as the pyrethroides8. Phytochemicals derivedfrom plant sources can act as larvicide, insect growthregulators, repellent and ovipositor attractant andhave different activities observed by many researchers9–11. However, insecticides of plant origin havebeen extensively used on agricultural pests and to avery limited extent, against insect vectors of publichealth importance.Northeastern region of India is considered as a majorbiodiversity hot spot. The eastern Himalayas range,which extends all through the northern border ofAssam, is a rich treasure house of many promisingmedicinal and aromatic plants. In the present communication,an attempt has been made to evaluate themosquito larvicidal efficacy of methanol and ethanolextracts of different parts of five indigenous plantsagainst Ae. albopictus (Diptera: Culicidae) and Culexquinquefasciatus larvae in laboratory conditions.Plant materials were collected from the foothill forestsof Sonitpur district, Assam bordering ArunachalPradesh during April and May 2005. They were segregatedas leaf, stem, bark, root and fruit/pericarp andair-dried in a shady place. Dried materials wereground in a table model grinder. The ground plant materialswere dipped in solvents (methanol and ethanol)Short Research Communications146 J VECT BORNE DIS 44, JUNE 2007in tightly capped jars separately for 48 h. The solventsalong with extracts were drained out, filtered andsemisolid extracts were obtained in vacuum usingrotary evaporator. The semisolid extracts were lyophilisedto obtain solid extracts. Stock solutions of desiredconcentration were prepared in distilled waterusing 1 ppm teepol as emulsifying agent and subsequentdilutions were made as per requirement. Larvicidalbioassay was carried out as per standard WHOtechniques in 500 ml glass beakers containing 250 mlof water and 25 numbers of late III or early IV instarmosquito larvae for various concentrations. Threedifferent concentrations of each extract were tried outat a time with six replicates. One control was kept witheach set of experiment and mortality was recordedafter 24 h. Five sets of experiments were conductedfor each extract. Tests were carried out under controlledlaboratory conditions (temperature 27 ± 2oC)against laboratory reared Ae. albopictus and Cx. quinquefasciatus(Diptera: Culicidae) larvae. Values obtainedwere subjected to log probit regression analysisto obtain LC50 and LC90 values with 95% confidencelimit12.The results showed that the larvicidal activity ofmethanol and ethanol extracts of five aromatic plantspecies against Ae. albopictus and Cx. quinquefasciatuslarvae varied according to plant species (Tables 1& 2). Methanol extract of Aristolochia saccata rootswas found to be the most effective against Ae. albopictuslarvae followed by ethanol extracts of A. saccata,Annona squamosa leaf and methanol extract ofA. squamosa leaf respectively. LC90 values of methanolextract of fruit/pericarp of Gymnopetelumcochinchinensis, bark of Caesalpinea species andethanol extract of stem of Piper species were obtainedat <200 ppm but methanol extract of seeds of G.cochinchinensis and stem of Piper species gave at<358 ppm against Ae. albopictus larvae (Table 1).Ethanol extract of leaf of A. squamosa was found tohave the most promising larvicidal activity againstCx. quinquefasciatus larvae. Methanol and ethanolextracts of A. saccata (root), methanol extract of A.squamosa (leaf) showed LC90 values at <100 ppmwhile methanol extract of G. cochinchinensis (fruit/pericarp), methanol and ethanol extract of Piper speciesshowed at <200 ppm and methanol extract of G.cochinchinensis (seed) showed at >302 ppm againstCx. quinquefasciatus larvae (Table 2).Long before the advent of synthetic insecticides,plants and their derivatives were used to kill pest ofagriculture, veterinary and public health. Sosan et al13reported larvicidal activities of essential oils of Ocimumgratissium, Cymbopogon citrus and Ageratumconyzoides against Ae. aegypti and achieved 100%mortality at 120, 200 and 300 ppm concentrationsrespectively. Similarly, it was reported that the essentialoil of Ipomoea cairica Linn. possesses remark-Table 1. Larvicidal efficacy of plant extracts against Ae. albopictus larvaeName of plant Part used Solvent used LC50 LC90 Regression equationAristolochia saccata Root Methanol 14.52 42.68 Y = 2.5683 *X+2.0164-do- Root Ethanol 17.30 58.51 Y = 2.3633 *X+2.0721Annona squamosa Leaf Methanol 20.26 86.59 Y = 1.9392 *X+2.4637-do- Leaf Ethanol 20.70 76.73 Y = 2.1991 *X+2.1020Gymnopetelum cochinchinensis Fruit/Pericarp Methanol 50.67 155.12 Y = 2.5821 *X+0.5927-do- Seed Methanol 100.42 312.45 Y = 2.3014 *X+0.3481Caesalpinea species Bark Methanol 53.66 169.41 Y = 2.3429*X+0.8638Piper species Stem Methanol 144.22 357.32 Y = 3.1826 *X–1.9688-do- Stem Ethanol 76.35 180.42 Y = 3.2525 *X–1.1333DAS et al : HERBAL MOSQUITO LARVICIDES 147able larvicidal properties as it could produce 100%mortality in the larvae of Cx. tritaeniorhynchus, Ae.aegypti, An. stephensi and Cx. quinquefasciatus mosquitoesat concentrations ranging from 100 to 170ppm14. Dwivedi & Kawasara15 found acetone extractof Lantana camara to be most effective against Cx.quinquefasciatus larvae at the dose of 1 ml/100 ml.Latha et al16 reported Piper longum and Zingiberwightianum extracts at 80 mg/l causing completemortality in Cx. quinquefasciatus and 60 mg/l for Cx.sitiens. In the present investigation LC90 values ofmethanol and ethanol extracts of roots of A. saccata,leaf of A. squamosa and fruits/pericarp of G.cochinchinensis against Ae. albopictus and Cx. quinquefasciatuslarvae ranged between 31.80 and 155ppm. Studies with essential oil of Ocimum americansand O. gratissium showed LC50 at 67 and 60 ppmrespectively against Ae. aegypti larvae17. In contrast,in the present study methanol and ethanol extracts ofroots of A. saccata, leaf of A. squamosa and fruits/pericarp of G. cochinchinensis against Ae. albopictusand Cx. quinquefasciatus larvae showed LC50 valuesbetween 6.96 and 57.4 ppm. Larvicidal activities ofthe plant extracts vary according to the plant species,the parts of the plant, the geographical location wherethe plants were grown and the application method.Plant could be an alternative source for mosquitolarvicides because they constitute a potential sourceof bioactive chemicals and generally free from harmfuleffects. Use of these botanical derivatives inmosquito control instead of synthetic insecticidescould reduce the cost and environmental pollution.Further studies on identification of active compounds,toxicity and field trials are needed to recommend theactive fraction of these plant extracts for developmentof eco-friendly chemicals for control of insect vectors.AcknowledgementThe authors are thankful to Dr. S.N. Dube, Director,Defence Research Laboratory, Tezpur, Assam, Indiafor extending necessary facilities, continuous supportand guidance in the study.References1. Brown AWA. Insecticide resistance in mosquitoes:pragmatic review. J Am Mosq Control Assoc 1986; 2: 123–40.2. Hayes JB Jr, Laws ER Jr. Handbook of pesticidetoxicology, v. 1. San Diego, CA: Academic Press 1991.3. Wink M. Production and application of pytochemicalsfrom an agricultural perspective. In: Van Beek TA, BretelerH, editors. Phytochemistry and agriculture. Oxford, UK:Clerendon Press 1993; p. 171–213.Table 2. Larvicidal efficacy of plant extracts against Cx. quinquefasciatus larvaeName of plant Part used Solvent used LC50 LC90 Regression equationAristolochia saccata Root Methanol 31.91 81.06 Y = 3.3086 *X-0.0062-do- Root Ethanol 19.83 60.44 Y = 2.5791 *X-1.6605Annona squamosa Leaf Methanol 17.70 64.29 Y = 2.1180 *X+2.3457-do- Leaf Ethanol 6.96 31.80 Y = 1.9441 *X+3.3592Gymnopetelum cochinchinensis Fruit/pericarp Methanol 57.4 108.3 Y = 4.1627 *X+2.3501-do- Seed Methanol 199.0 301.6 Y = 1.7586 *X+11.0557Caesalpinea species Bark Methanol 42.27 207.13 Y = 1.7586 *X+2.0573Piper species Stem Methanol 70.10 113.90 Y = 5.669 *X+5.4992-do- Stem Ethanol 57.4 108.3 Y = 4.1627 *X+2.3501148 J VECT BORNE DIS 44, JUNE 20074. Cheng SS, Chang HT, Chang ST, Tsai KH, Chen WJ.Bioactivity of selected plant essential oils against theyellow fever mosquito Aedes aegypti larvae. BioresTechnol 2003; 89(1): 99–102.5. Isman MB. Pesticides based on plant essential oils.Pesticide Outlook 1999; p. 68–72.6. Harve G, Kamath V. Larvicidal activity of plant extractsused alone and in combination with known syntheticlarvicidal agents against Aedes aegypti. Indian J ExptlBiol 2004; 42: 1216–9.7. Desai ST. Potency of larvicidal properties of plantextracts against mosquito larvae under laboratoryconditions (M.Sc. Dissertation submitted to MumbaiUniversity Mumbai, India 2002).8. Mwangi RW, Mukiama TK. Evaluation of Melia volkensiextract fractions as mosquito larvicides. J Am MosqControl Assoc 1988; 4: 442–7.9. Babu R, Murugan K. Interactive effect of neem seed kernaand neem gum extract on the control of Culex quinquefasciatusSay. Neem Newsletter 1998; 15(2): 9–11.10. Venketachalam MR, Jebasan A. Repellent activity ofFerronia elephantum Corr. (Rutaceae) leaf extract againstAedes aegypti. Biores Technol 2001; 76(3): 287–8.11. Venketachalam MR, Jebasan A. Larvicidal activity ofHydrocotyl javanica Thunb (Apiaceae) extract against Cx.quinquefasciatus. J Exptl Zool India 2001; 4(1): 99–101.12. Finney DJ. Probit analysis, III edn. Cambridge: CambridgeUniversity Press 1971.13. Sosan MB, Adewoyin FB, Adewunmi CO. Larvicidalproperties of three indigenous plant oils on the mosquitoAedes aegypti. Nigerian J Natl Prod Med 2001; 5: 30–3.14. Thomas TG, Rao S, Lal S. Mosquito larvicidal propertiesof an indigenous plant, Ipomoea cairica Linn. JapaneseJ Infect Dis 2004; 57: 176–7.15. Dwivedi SC, Karwasara K. Larvicidal activity of fiveplants extracts against Culex quinquefasciatus. Indian JEntomol 2003; 65(3): 335–8.16. Latha C, Vijhayakumar PD, Velayudhan S, Joseph A.Biological activity of indigenous plant extracts as mosquitolarvicides. Indian J Exptl Biol 1999; 37: 206–8.17. Cavalcanti ESB, Morais SM, Lima MAA, Santana EWP.Larvicidal activity of essential oils from Brazilian plantsagainst Aedes aegypti L. Mem Inst Oswaldo Cruz 2004;99(5): 541–4.Corresponding author: Dr. N.G. Das, Medical Entomology Division, Defence Researc

Information Needs of Library Users of Selective Metallurgical Institutions in Jharkhand

This paper highlights on the R&D information needs of scientists, engineers, managers and researchers in the field of metallurgy working in selective metallurgical institutions in Jharkhand, India. The study revealed that the R&D groups of these organisations used a variety of formal and informal information sources effectively in meeting their research information needs. Apart from literature search, the teams attend meetings, discussions, seminars, workshops and conferences as the major informal sources of acquiring knowledge, sharing experiences with their colleagues and experts and to establish professional contacts for exchange of knowledge. Government-funded organisations have a provision of regular budget to support their knowledge resources whereas public funded organisations are mostly project-based funding and fluctuates from time to time as also in the case of privately funded, which are mostly need-based. Similar is the case for document procurement services and knowledge sharing in all the three kinds of metallurgical organisations

Advanced gravity separation

Gravity separation methods which exploit the difference in densities of minerals to bring about a separation are the oldest beneficiation techniques known to mankind. Although with the advent of froth flotation, the relative importance of gravity separation in twentieth century has gone down, substantially higher tonnage of material is treated by gravity concentration than by flotation. Gravity separation is by far the most utilized concentration technique and is an integral part of most mineral processing flowsheets including the processing of coal, beach sands, iron, gold, platinum, tin, tungsten and chromium ores. Gravity based processes are comparatively more economical and environment friendly

Impact of grant-in-aid projects at CSIR-National Metallurgical Laboratory, India: A bibliometric study

The purpose of this study is to evaluate the impact of 204 Grant-in-Aid projects carried out at CSIR-National Metallurgical Laboratory, India during 1995-2010 through Bibliometric method. Unearths the impact of projects in the light of current needs to sustain in future. The data pertaining to study were generated through structured questionnaire. The output-identified as deliverables of each project includes, cash flow, process developed, patents, copyright, and technology transferred, academic contribution and research papers published through projects .The quality of papers were traced out through citation and impact factor. The Projects have been classified at different level of research- basic research, applied research, industrial research. The data further presented according to the level of research to accommodate 204 projects. The duration of the projects ranged from 6 months to 5 years. A group of 27 subject areas have been identified for all the projects, fall in the domain of Metallurgy and Materials Sciences and allied subjects .The value of projects were estimated around 55 Crore Rupees. About 97% projects were accomplished in scheduled time. The R&D output reflects that 55 processes were developed and only one technology could be transferred. However 21 technologies are under negotiation for transfer to different parties. During the tennure of projects, 40 patents and 14 copyrights were filed. About 58 students from various reputed academic institutions were benefited through projects. A total of 608 research papers were reported based on projects findings. The trends of publications during 16 years show that SCI papers are in increasing trends and reflects a healthy sign as performance indicators of the sponsored projects. The projects under basic research contributed a maximum of 226 papers with 845 citations, shared 64.50% of the total 1310 citations. The average impact factor of papers was 1.552. The highly cited papers published in the area of water quality-assessment, received 88 Citations, other highly cited papers fall in the domain of corrosion protection and prevention, waste management and utilization and materials science and technology. The output of the present work will be useful for scientists and decision makers to judge the impact of Grant- in- Aid projects in the light of current global scenario and making project selection mechanism more effective by tailoring to the current needs of the society

Towards Sustainable Alumina Production

This paper, an overview • of research pursued at NML towards sustainable alumina production, ',deals with: (a) a chemical beneficiation of red mud to recover all its constituents, and (b) a novel process to reduce the alumina and soda content of red mud using mechanochemical activation (MA) of bauxite. As a part of the study on chemical-beneficiation of red mud, phase stability in the system Fe203-A1203-Na2CO3- C has been investigated using free energy minimization. Using these results, a process involving solid-state carbothermic reduction of red mud in the presence of soda, water leaching for alumina recovery and magnetic separation of leach residue for the sepa-ration of iron and TiO2 rich _fraction has been evaluated. Experimental results are explained using extensive X-ray diffraction and SEM-EDS studies on various solid residues generated in the different stages of the process. Mecha-nical activation of bauxite is investigated: (a) as pre-treatment to the Bayer process; and (b) mechanochemical leaching of bauxite, i.e. simultaneous milling and leaching of bauxite. The superiority of mechanochemical leaching over the existing Bayer 1. process practice and MA as pretreatment has been established. Using the novel process the approach of mechanochemical leaching, reduc-tion in soda content of red mud to less than 1% and alumina content to less than half is possible with additional benefits in terms of moderation in process condition, simplicity of the process and efficient utilization of energy. Merits of the investigated processes have been highlighted vis-à-vis previous studies on red mud utilization and minimization of its enviro-nmental impact

Pollution and its Control in Copper Industry

Pollution is a result of development or civilization. "Nature" does not pollute but "Industry " does. The earth being the main source of most minerals, its protection from misuse is of major significance . The wide spread industrialisation in absence of a predefined direction contributes significantly to pollution , depletion of useful natural resources and ecological imbalance. The matter has been getting serious attention now to combat risk to life and to ensure conservation of resources. The paper presents the extent, nature and effects of pollution by copper industry. It also highlights various measures to control environmental degradation and to reduce the effects of waste and intermediate products on environment. Possible safety measures and tolerable limits of discharges of effluents into air and water are also indicated. Recent technologies to control pollution in copper industry have been discussed

Bibliography (Part - 4) The publications by the staff of Central Marine Fisheries Research Institute 1996-2006 (A Diamond Jubilee Publication)

Central Marine Fisheries Research Institute (CMFRI) has been documenting bibliographies on various topics. The Institute has published over a dozen such bibliographies on various finfishes and shellfishes. Three bibliographies were published during 1986, 1992, 1998 listing the publications of the staff of CMFRI from 1948 to 1995. Since then, tremendous data was generated from both inhouse and sponsored projects, leading to a good number of research publications in national and international journals. A sincere effort has been made in the present endeavour incorporating all the publications of the staff from 1996-2006. A total of 2039 titles have been listed in the Bibliography Part IV including 25 titles pertaining to period prior to 1995 which could not find a place in the earlier bibliography

Effect of Gamma Radiation on Survival and Fertility of Male Anopheles stephensi Liston, Irradiated as Pharate Adults

Effect of radiations on the survival and fertility of male Anopheles stephensi Liston was evaluated in the laboratory with 70 and 100 Gy radiation dose. Irradiation of pharate adults with 100 Gy dose resulted in reduced emergence and longevity as compared to control (0 Gy) and 70 Gy dose. Fecundity and fertility of female An. stephensi mated with male irradiated as pharate adults was determined upto four blood meals. Significant decline was observed in fecundity after each blood meal at 100 Gy as compared to 0 Gy and 70 Gy irradiation. Similarly, the fertility was also decreased after each blood meal at 100 Gy irradiation. The present study indicates the suitability of 100 Gy dose for irradiation of pharate adult stage of mosquito as a part of mosquito management.--------------------------------------------------------------------------------------------------------Defence Research Laboratory, Tezpur, India*Corresponding author, Email: dhiman_81@ indiatimes.com Please Cite This Article As:Kavita Yadav, Sunil Dhiman Indra Baruah and Lokendra Singh. 2010. Effect of Gamma Radiation on Survival and Fertility of Male Anopheles stephensi Liston, Irradiated as Pharate Adults. J. Ecobiotechnol. 2/4:06-10.Â

Red Mud Pollution Problems : Some observations

The problem of pollution caused by red mud disposal and alternatively its utilisation has remained unsolved eversince industrial production of alumina from bauxite started as a commercial venture in 1860. Indigenous efforts to utilise this collosal waste have been limited since R&D efforts in this direction lacked coordination and adequate funding. In this paper the scientific and technological approaches to tackle this problem have been discussed and few conventional as well as novel approaches are presented. While looking for economics of alumina production, ecology has totally been ignored and time has come to realign our thinking and planning process to find a tangible solution