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Current Research in Microbiology and Biotechnology Vol. 1, No. 4 (2013): 124-126 Research Article Open Access

IISSSSNN:: 22332200--22224466

Larvicidal activity of Aloe vera leaf extract on Culex Salinarius Ramesh Kumar Verma1*, Ashok Kumar Saxena1 and S. Rajarajan2 1 Department of Zoology, DAV College, Kanpur (UP India) 2 P.G. & Research Department of Microbiology and Biotechnology, Presidency College- Chennai, India * Corresponding author: Ramesh Kumar Verma, email: rps.verma32@gmail.com

ABSTRACT The present study explored the effects of Aloe vera leaf extract larvicidal activity against the Culex salinarius. The bio-efficacy of Aloe vera leaf extract, were assessed against the first to fourth instar larvae of Culex salinarius, under the laboratory conditions. The larvicidal activities of Aloe vera leaf extract were penetrated of larvae body through the oral injetion and larval membrane by a woody substance as like Lignin. The results revealed that the different concentrations of crude extract of Aloe Vera resulted in considerable mortality for 1st to 4th instar larvae at 0.1 and 0.2mg/ml. Among the larval instars, instar 1st and 2nd were found to be more susceptible. No mortality was observed in the control. The results suggest the problems larvicidal activity of Aloe vera leaf extract against Culex salinarius. The study suggests that leaf extracts can be used as an ideal eco-friendly approach for the bio-control of Culex larvae. Insecticides of botanical origin may serve as suitable alternative bio-control techniques in the future.

Keywords: Aloe-vera, Culex salinarius, Lignin, Larvicidal activities, Insecticides

INTRODUCTION Culex salinarius is a species that feeds both on birds and mammals. This species is a bridge vector which transmits West Nile Virus from birds to mammals [1]. Mosquitoes transmit serious human diseases, causing millions of death every year in India [2]. Culex is a genus of mosquito and is important in the females of several species are blood eating pests and serve as vectors of pathogens causing human disease, such as west Nile virus, filariasis, Japanese encephalitis(JE), St. Louis encephalitis (SLE) and avion malaria [3]. Species of Culex include a complex known as “house mosquito” and, more recently, “West Nile mosquito” because of their involvement in the transmission of West Nile Virus. Seven species occur in Indiana, of which four are involved in the transmission of West Nile Virus among birds and potentially to humans and horses. In addition to West Nile Virus, certain species of Culex are known to transmit St. Louis Encephalitis Virus and Western Equine Encephalitis Virus [1]. Use on synthetic insecticides to control of vector mosquito has caused physiological resistance and environmental effect. Insecticides of botanical origins have been reported as useful controlling agents of Culex species [4]. Mosquito control has medical importance as well as global

importance. In the context of ever increasing trend to use more powerful synthetic insecticides to achieve immediate results in the control of mosquitoes, an alarming increase of physiological resistance in the vectors, its increased toxicity to non-target organism and high costs are noteworthy [5]. The use of different parts of locally available plants and their various products in the control of mosquitoes has been well established globally by numerous researchers. The larvicidal properties of indigenous plants have also been documented in many parts of India along with the repellent and anti-juvenile hormones activities [6]. Aloe vera is a perennial plant belonging to the family of Liliaceae, of which there are about 360 species [7]. Aloe vera has a long association with herbal medicine, although it is not known when its medical applications were first suspected. Early records of Aloe vera use appear in the Ebers Papyrus from 16th century BC [8]. Aloe vera has been widely grown as an ornamental plant. The species is popular with modern gardeners as a putatively medicinal plant [9]. Since, 1986 Aloe vera has been used as a traditional medicine and as an ingredient in many cosmetic products; it has gained high.

Received: 17 May 2013 Accepted: 30 May 2013 Online: 01 July 2013

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MATERIALS AND METHODS Synthesis of Aloe vera leaf extract Fresh Aloe vera leaves were collected from personal Botanical Garden, Swarup Nagar in Kanpur, U.P. India, and washed with distilled water. 50 gm. of fresh Aloe Vera leaves were cut into small pieces prior grinding in a mortar and pestle and the aqueous extract was collected and filtered. Culture of Culex salinarius larvae with Aloe Vera leaf extract The species of larvae of Culex salinarius used in this study were collected from stagnant water bodies by a hand net (fig.1) at Aryanagar, Kanpur City, U.P., India. They were transported in plastic buckets containing clean water to the lab. Larvae were categorized based on their size as large and small. The large sized Culex salinarius larvae were about 0.6 cm and the small sized larvae measured about 0.2 cm in length. For the present study both sized larvae (1st to 4thinstars stage) were used and were placed in 3 batches of 50 larvae each in petri dishes. The effect of Aloe vera leaf extract on the viability of Culex salinarius larvae was determined at 10 and 20% concentration. The larvae were transferred in three 250 ml glass beakers containing 200 ml of de-chlorinated water, two beakers were added 20 ml and 40 ml of desired concentration of Aloe vera leaf extracts and one beaker was control devoid of extract. Dog biscuit and sugar particles were added as nutrients in the ratio of 2:1. They were maintained at 25-31°C, under 14:10 light and dark photo period cycle until the adult emerged. The prepared Aloe vera leaf extract was transferred into larvae culture pots as shown in Fig.2. The total larval duration (days) was calculated from day one to the emergence of imago or larval death day. A number of dead larvae in each batch were counted every day morning. The treated larva was mounted on a slide and examined under a microscope (Megnus MLM - Japan) for image capture on a Dewinter digital Microscope camera (Dewinter Technologies, Italy). RESULTS AND DISCUSSION It has been observed that Aloe vera leaf extract effected the viability of larvae of Culex salinarius. The mortality rate was found to be 70 and 84% throughout the experiment for 10 and 20% extract concentrations respectively. In the control group no mortality was recorded so 100% larvae were converted to adult within 11 days of experiment. These studies indicate that Aloe Vera leaf extract was found to be most effective for 1st to 2nd stages larvae but low effective for 3rd and 4th stages larvae. The reason might be the presence of compounds in extract might contribute to the death of larvae. The extract displayed more larvicidal activity as it caused 44% mortality within 24 h at 20% concentration. The mortality effect of Aloe vera leaf extract against Culex salinarius larvae is given in Tables- 1and 2.

Figure 1. Types of nets used.

Figure 2. First beaker shows the 10% concentration, second beaker show the 20% concentration of Aloe vera leaf extract with each beaker containing 50 mosquito larvae in 200 ml of water. Third beaker shows the control with 50 mosquito larvae and 200 ml water. Table 1. Explains the Mortality graph of larva versus Aloe vera leaf extract concentration against Culex salinarius.

CONCLUSION This result clearly reveals that the leaf extract of Aloe vera has important medicinal and therapeutic properties. In conclusion, the results obtained from this study may be useful in the search for new, more selective and biodegradable larvicidal natural compounds. Application of these extract to mosquito breeding habitats may lead to promising results in mosquito management programmes. ACKNOWLEDGEMENTS The Authors are grateful thanks to Department of biotechnology (DBT), New Delhi, for providing scientific platform and financial support for this project.

RK Verma et al. / Curr Res Microbiol Biotechnol. 2013, 1(4): 124-126

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Table 2. Explain the effect of Aloe vera leaf crude extract on larvae of Culex salinarius and their Mortality and conversion percentage calculated in 24 hours.

Corrected mortality of Aloe vera (cone. 10%) = 58 (L) +12 (P) =70% Corrected mortality of Aloe vera (cone. 20%) = 66 (L) +18 (P) =84% Corrected mortality of Control = 0% (No mortality) REFERENCES

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Aloe vera leaf extract concentration % 10 % 20 % Control Day

Larva Pupa Conversion Larva pupa Conversion Larva pupa Conversion 1st 18 00 00 44 00 00 00 00 00 2nd 22 00 00 16 00 00 00 00 00 3rd 12 00 04 02 00 10 00 00 00 4th 04 04 24 04 06 04 00 00 00 5th 02 08 02 00 12 02 00 00 24 6th 00 00 00 00 00 00 00 00 30 7th 00 00 00 00 00 00 00 00 16 8th 00 00 00 00 00 00 00 00 04 9th 00 00 00 00 00 00 00 00 08 10th 00 00 00 00 00 00 00 00 06 11th 00 00 00 00 00 00 00 00 12 Total 58 12 30 66 18 16 00 00 100

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