Effect of Tulsi and Neem Extract on Mosquito Larvae

Effect of Tulsi and Neem Extract on Mosquito Larvae Research question: What are the effects of medicinal plants like Ocimum sanctum (tulsi) and Azadirachta indica (neem) extract on the mortality of Culex larvae? ABSTRACT The effect of Neem and Tulsi on mosquito larvae. The project is aimed at finding natural pesticides or bio-pesticides that effectively control the mosquito population by killing mosquito larvae. They could be used as alternatives to the current pesticides used that have adverse effects on the environment and other species besides the target pest. Mosquitoes are hosts for a very large number of diseases and therefore keeping larvae under control and disallowing the emergence of adult mosquitoes is essential. Two plant extracts have been tested; Neem and Tulsi. The initial hypothesis was that both extracts would have some effect on the larval development and cause mortality in the larvae due to the properties of both plants. The secondary initial hypothesis was that Neem extract would be significantly more effective in killing the larvae than Tulsi at the same percentage. Concentrations of 1% to 10% of each extract were prepared and 10 trials each performed with 10 larvae were undertak en. The samples were checked on after 12 hours and once again after 24 hours and the number of larvae killed in each case was recorded. The results were conclusive and both extracts were very effective at killing larvae at 10% with Neem killing an average of 10 larvae out of 10 and Tulsi 9.6  ± 0.52. However t-values showed that the initial hypothesis stating that Neem would be more effective at all concentrations was incorrect and only 2%, 9% and 10% were significantly more effective in 24 hours with t values of 3.13, 2.92 and 2.43 respectively (> table value of 2.10). This means that in 2%, 9% and 10% concentrations, Neem should be used instead of Tulsi as it is significantly better. This is all very exciting as environmentally safer pesticides can be developed from these two plant extracts. 1. Introduction Research question: What are the effects of medicinal plants like Ocimum sanctum (tulsi) and Azadirachta indica (neem) extract on the mortality of Culex larvae? The conservative pesticides are augmented to combat complicated pest problems in mosquitoes. In human health during the past few decades these pesticides played an important role in the inhibition of diseases caused by mosquitoes either by inactivating or killing these mosquitoes. Later on when these pesticides are getting accumulated in the environment proved to be hazardous to the environment and mankind. Frequent application of synthetic organic insecticides resulted into pest resistance and outbreak. Most of the insecticidal compound falls within four main classes namely organochlorides, organophosphates, carbamates and pyrethroids. Out of these the major classes of insecticides, the insecticides used in present situation are organophosphates and carbamates. There are problems of pesticides resistance and negative impacts on non-target organisms including man and the environment.[1] Environment problems due to the insecticides and pesticides such as destruction of beneficial organisms, non-target pest, some of the pesticide residues in the host plant resulting in stunted grow or killing other organisms have come to an end. This work is basically taken up by some of the herbal plants. These herbal plants possess some of the active ingredients which are eco-friendly but simultaneously have a severe effect on the mosquito populations.[2] Medicinal plants are the most promising source and under extensive trails for their biological activity against various mosquito larvae. During the last 10 to 15 years, interest in botanical insecticides has increased to look for substitutions for synthetic insecticides with those based on naturally occurring substances. The use of botanicals in pest management is not only useful for suppression of pest population but also helps to maintain the sound ecological balance.[3] BOTANICALS IN USE The groups of plant possessing insecticidal substances are enormous. More than 2400 species of the plants in India possess insecticidal properties3. In the middle of the 17th century, most of the economically important natural plant compounds obtained from the plants like neem, tulsi, adathoda, chrysanthemum, turmeric, garlic, tridax etc. are used in commercial insect control. Despite the relative safety of the well-known botanical insecticides, most of these substances have their drawback hindering large-scale application. The chemicals obtained from these plants are unstable in the sunlight and are rapidly metabolized thus limiting their potency and application.[4] Botanical insecticides break down readily in soil and are not stored in animal and plant tissue. Often their effects are not as long lasting as those of synthetic insecticides and some of these products may be very difficult to find. The plant parts used for extraction or assay were the leaves, roots, tubers, fruits, seeds, flowers, the whole plant, bark, sap, pods and wood. The most commonly utilized parts were the leaves, roots. The plant families Asteraceae, Fabaceae and Euphorbiaceae contain most of the insecticidal plant species reported. Recently several other plants viz. Neem, Adathoda, Chrysanthemum, Turmeric, Onion, Garlic, Ocimum, Ginger and some other plants have been reported as insecticidal plants which can be used in insecticide preparation. The leaf extracts of Tulsi (Ocimum basilicum, O. sanctum) and vetiver (Vetivera zizanoides) are useful in controlling leaf miners in potato, beans, eggplant, tomato, chilies, etc. Some of the plants having herbal insecticide princip les are presented on table. Source of Plant Nature of action Chemical Group Plant parts Azadirachta indica Contact poison Azadirachtin Leaves, seed Ocimum sanctum Contact, Repellent Tulsin Leaves Chrysanthemum Contact, Repellent Pyrethrin I Flower, seed Tridax procumbens Contact poison Flower Zingiber officinale Repellent zingiberene Rhizome Among all the important insecticidal plants, Neem (Azadirachta indica) is the most promising source of bio-pesticide and its various formulations are extensively used for pest control.[5] Neem leaves, stems, seeds and oil have been used for pest control in sericulture.[6] The limonoids present in it and its products have made it a harmless to mankind while functioning as insecticide, bactericide, fungicide, pesticide etc. It is likely to provide a solution to many of pest and disease problem in sericulture.[7] Generally, extracts of plant leaves or seed are prepared and sprayed; otherwise, seeds are dried under sunshade, powdered finely and applied as dust. More than 20 Neem based biopesticides are available in the market (Table 3). Neem gets biodegraded in a matter of weeks when exposed to sunlight or in soil. Neem products are highly photodegradable and normally degrade within a week. No problem of development of pest resistance and resurgence has been reported from neem products. Hence they have characteristics suitable for IPM strategy. Much of the informations are available on insecticidal properties of plants having some sort of toxic property against insects. The plant parts to be used should be removable: leaves, flowers or fruit and harvesting should not mean destruction of the plant. Azadirachta indica: Neem is perhaps the most well known of all herbs and has been used in ayurveda in India for centuries. The active ingredient in Azadirachta indica (neem) is azadirachtin. It a member of the Meliaceae family and is a botanical cousin of mahogany. Neem is very hard and virile. Neem is especially useful due to its climatic tolerance that allows it to be grown all over the world though it is usually found in tropical regions. It has insecticidal, antifeedant, growth regulating and development-modifying properties and has properties that make it attractive in insect control. It reduces fecundity and longevity as well as increased development time of immature insects. On insects it has been shown to act as a growth retardant and cause molting disorders, change of behavior and morphogenetic defects. Mosquito control is essential as they act as carriers for malaria, filariasis and a host of other diseases as well as being a nuisance. There is a high demand for a less environmentally harmful insecticide as the ones currently used have high neurotoxic effects. Recent studies have also demonstrated neem-induced effects on vitellogenesis and severe degeneration of follicle cells during oogenesis in mosquitoes. It also has several medical properties such as a cure blood morbidity, biliary afflictions, itching, skin ulcers, burning sensations and pthysis. It is also an effective cure against ringworm, eczema and scabies. In English the tree is known as margosa and attains a maximum height of 40 to 50 metres. Ocimum Sanctum: Tulsi is an aromatic plant in the Lamiaceae family. Tulsi has been used for thousands of years in Ayurveda due to its diverse healing properties. Tulsis extracts are used in ayurvedic remedies for common colds, headaches, stomach disorders, inflammation, heart disease, various forms of poisoning, and malaria. Traditionally, tulsi is taken in many forms: as herbal tea, dried powder, fresh leaf, or mixed with ghee. Essential oil extracted from Karpoora Tulsi is mostly used for medicinal purposes and in herbal cosmetics, and is widely used in skin preparations due to its anti-bacterial activity. For centuries, the dried leaves of Tulsi have been mixed with stored grains to repel insects.[8] These plants in harmonious integration with other safe methods of pest control like biological control can provide eco-friendly and economically viable solutions for pest problems in near future. ADVANTAGES Plants producing the compounds having insect growth regulators (IGR), feeding deterrents, repellents and confusants activities are known by the farmer because most of the time they grow in the same general area. Some of these products may be these products act very quickly inhibiting insect feeding even though long term they do not cause insect death. Since most of these products have a stomach action and are rapidly decomposed they may be more selective to insect pests and less aggressive with natural enemies. Most of these compounds are not phytotoxic and have rapid action and low toxicity to mammals and plants. Resistance to these compounds is not developed as quickly as with synthetic insecticides. DISADVANTAGES Most of these products are not truly insecticides since many are merely insect deterrents and their effect is slow. They are rapidly degraded by UV light so that their residual action is short and breakdown is rapid, requiring more precise timing of and/or more frequent application. Not all plant insecticides are less toxic to other animals than the synthetic ones. They are not necessarily available and sometimes cost is more. Most of them have no established residue tolerances and there is lack of test data and sometimes lack of state registration of some materials. There are no legal registrations establishing their use. Not all recommendations followed by growers have been scientifically verified. The above statements are altered if you find anything that can be added or deleted you can do it. Insects adapt themselves to aquatic habitats inspite of their terrestrial origin. The aquatic and semi-aquatic insects are remarkable for their diversity of forms, reflecting adaptation to a wide variety of niches such as salt water pools, saline ponds, hot springs, high mountain lakes, large rivers, temporary and permanent ponds. Mosquitoes are known as vectors of the pathogens causing human diseases. They belong to the order Diptera; the true flies. Like all flies they have two wings but unlike other flies they have scales and the females have sucking proboscis. There are over 2500 species of mosquitoes. Culex mosquitoes are known to be painful and persistent biters and are a nuisance. The reason why I chose this topic is because the pesticides that are currently used in pest control contain chemicals that have diverse side effects on the environment and organisms other than the target pest. I decided to use natural substances found in nature and see if they would work as a form of pest control instead. I have used two extracts; Neem and Tulsi, in order to see which one was more effective in killing these mosquitoes. Neem, Tulsi and eucalyptus have been used as they are prevalent in the tropical and sub-tropical countries of Africa and Asia with a large mosquito population and there have been significant prospects of being used as an insecticide on a commercial scale due to their useful properties. Aim: In early literature mentioned above it was noted that the mosquitoes inhibit both temporary and fresh water stagnant bodies and they are found in abundance causing nuisance to the human population. The aim of the present study was undertaken on the following aspects 1. To determine the number of Culex larvae killed in 12 hours and 24 hours using different plant extracts like Neem and Tulsi in crude form. 2. To determine the number of Culex larvae killed in 12 hours and 24 hours by Neem and Tulsi under various concentrations (1%-10%). 3. To determine the statistical analysis t tests were performed. 2. Materials and Method 2.1. Materials / Equipments 250 ml beaker, Mortar and pestle, Pipette, Stirrer, Water, Fishing net (for catching larvae), Dropper, Watch glass, Petri dishes. Culex larvae: For the present study, the larvae of Culex mosquitoes were used throughout the investigation. These larvae were chosen because they were most abundant in the water bodies which are very active fast wriggling movement. The Culex larvae were collected from stagnant water bodies at Varthur Lake in Bangalore (fig.1) using a hand net. 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 larvae were about 0.7 cm and the small sized Culex larvae measured about 0.2cm in length. For the present study I have used only large sized larvae (3rd and 4th instars stage). Medicinal plants used as extracts: Botanical name Common name Medical Purposes Part of plant used Ocimum sanctum Tulsi Used to treat digestive problems Young leaves Azadirachta indica Neem Kills pathogens. Used to cure skin ailments. Young leaves Preparation of Stock solution: Azadirachta indica: [Neem] I collected neem leaves from my school campus. Only young leaves were collected and dried in the absence of sunlight in the shady region. The complete method of preparing 10% stock solution of this plant extract is mentioned below. 10 grams of dried young leaves were then grinded using mortar and pestle along with methanol and dried. Then add 100 ml of distilled water to make out 10% stock solution. Then the 10% neem stock solution was decanted after centrifugation. Now from this 10% stock solution different concentration solutions in percentage were prepared [ranging from 1% 10%] i.e., 10ml of 10% stock solution in 90ml of distilled water gives 1%, 20ml of 10% stock solution in 80ml of distilled water will give 2%, 30ml of 10% stock solution in 70ml of distilled water will give 3%, 40ml of 10% stock solution in 60ml of distilled water will give 4%, 50ml of 10% stock solution in 50ml of distilled water will give 5%, 60ml of 10% stock solution in 40ml of distilled water will give 6%, 70ml of 10% stock solution in 30ml of distilled water will give 7%, 80ml of 10% stock solution in 20ml of distilled water will give 8%, 90ml of 10% stock solution in 10ml of distilled water will give 9%, and for 10% the stock solution itself was used. Ocimum sanctum: [Tulsi] I collected Tulsi leaves from my school campus. Only young leaves were collected and dried in the absence of sunlight in the shady region. The complete method of preparing 10% stock solution and the different concentration of this plant extracts in percentage was done by same method as mentioned above in Neem. 2.2. Method / Procedure Mortality of larvae using crude plant extracts: 1. The large sized Culex larvae were taken in the petridishes. 2. 5 ml of crude plant extracts of neem and tulsi were taken in the different test tubes. 3. 10 larvae were introduced in each test tube at the same time. 4. Ten trails were carried out for the two different plant extract. 5. The number of larvae killed was recorded for 1hr, 12hr and 24 hr. 6. Larvae were feed with dog biscuit powder. 7. Comparative analysis was carried out graphically between the two plant extracts at different time period. Mortality of larvae using different concentration of plant extracts: 1. The large sized Culex larvae were collected and separated in the petri dishes. 2. 5 ml of 1% Neem extract was pipetted in the test tube using a graduated pipette. 3. 10 Culex larvae were introduced and the time was noted. 4. Ten trials were carried out at the same time for different concentration. 5. The larval mortality was recorded for 12 hours and 24 hours. 6. The same procedure was followed for different concentrations [2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% 10%] of the Neem extract. 7. During this experiment the larvae was feed with dog biscuits in powdered form. 8. The above mentioned procedure was also carried out using Tulsi plant extract. 9. A comparative study of larval mortality was made by using these two plants extract on the Culex mosquito larvae. The percentage of mortality (which will give us an indication of the effectiveness of the extract) will be calculated using the following formula. Percentage of mortality = Number of dead larvaeNumber of larvae introduced X 100 2.3. Variables Dependant variable- Number of larvae killed Independent variable-Different concentration of neem extract and tulsi extract, different time period [1hr, 12 hrs, 24 hrs] Controlled variable-Number of larvae, Volume of water, Temperature, food 2.4. Hypothesis Hypothesis 1 Null Hypothesis (Ho): Neem and Tulsi have no significant the mortality of the Culex larvae. Positive hypothesis (H1): Neem and Tulsi have a significant effect on the mortality of the Culex larvae. Hypothesis 2 Null Hypothesis (Ho): There is no significant difference in the rate of mortality between Neem and Tulsi plant extracts. Positive Hypothesis (H1): There is a significant difference in the rate of mortality between Neem and Tulsi plant extracts. 3. Results 5.1 Mortality of larvae using crude plant extracts The Culex larvae were exposed to different plant extracts in crude form to study the mortality rate. The number of Culex larvae killed was recorded after 1 hour, 12 hours and 24 hours separately (Table 1). In one hour the mean number of larvae killed by Neem was 4.9 ±0.74 and for Tulsi it was 3.5 ±1.08. As time progresses the difference in effectiveness becomes less and the two extracts are approximately equal. The crude extract of Neem was more effective than Tulsi in one hour duration. At 12 hours the mean number of mosquitoes killed were 9.2 ±1.14 and 8 ±1.05 respectively. At 24 hours the Neem and Tulsi extracts showed almost the same level of effectiveness with mean values of 10 and 9.7 ±0.48 respectively. The crude form of Neem extract was significantly more effective than Tulsi in killing the Culex larvae in 1 hour and 12 hours. However in 24 hours there is no significant difference in the effectiveness of Neem and Tulsi plant extracts. 5.2 Mortality of larvae using different concentration of plant extracts: 5.2.1. Neem: The mortality of the larvae using different concentrations of Neem extract was recorded. At 1% concentration the mean number of larvae killed was noted to be 2.4  ± 0.52 in 12 hours and 3.5  ± 0.53 in 24 hours. At 10% concentration the highest mortality rate was recorded as 9.6  ± 0.52 and 10 for 12 hours and 24 hours respectively. As the concentration of the Neem extract increased, the mortality of the larvae also steadily increased (Table 2). 5.2.2. Tulsi: The mortality of the mosquitoes for Tulsi extract was recorded in the same way as Neem. At 1% concentration the mean number of larvae killed was noted to be 1.8  ± 0.63 in 12 hours and 3  ± 0.67 in 24 hours. At 10% concentration the highest mortality rate was recorded as 8.7  ± 0.67 and 9.6  ± 0.52 for 12 hours and 24 hours respectively. As the concentration of the Tulsi extract increased, the mortality of the larvae also steadily increased (Table 3). Table 1 : Mortality of larvae using crude plant extract Trail s No. of larvae killed 1 hour 12 hours 24 hours Neem Tulsi Neem Tulsi Neem Tulsi 1 5 2 10 9 10 10 2 4 3 10 6 10 9 3 5 5 7 7 10 10 4 6 4 10 8 10 10 5 4 3 8 7 10 9 6 5 4 10 9 10 10 7 6 4 9 8 10 10 8 4 5 10 9 10 10 9 5 3 8 9 10 10 10 5 2 10 8 10 9 Mean  ± S.D 4.9 ±0.74 3.5 ±1.08 9.2 ±1.14 8 ±1.05 10 ±0 9.7 ±0.48 T- test 3.38 2.45 1.96 Calculations T value= Degree of freedom = 20 -2 = 18 Level of significance= 0.05 Table t value = 2.10 Neem and Tulsi in 1 hour Calculated T value= 4.9- 3.5 / √(0.74)2 + (1.08)2 /10 = 3.38 Neem and Tulsi in 12 hours Calculated T value = 2.45 Neem and Tulsi in 24 hours Calculated T value = 1.96 Graph Showing the mortality of larvae using crude plant extract Table 2 Mortality of larvae using different concentration of Neem extracts S. No. Different concentration of Neem extract [%] Mean No. of larvae killed 12 hours 24 hours 1 1% 2.4  ± 0.52 3.5  ± 0.53 2 2% 3.2  ± 0.63 4.3  ± 0.48 3 3% 3.9  ± 0.57 5  ± 0.67 4 4% 4.6  ± 0.7 5.9  ± 0.74 5 5% 5.3  ± 0.67 6.4  ± 0.7 6 6% 5.8  ± 0.42 7  ± 0.67 7 7% 6.5  ± 0.85 7.5  ± 0.53 8 8% 7.4  ± 0.52 8.6  ± 0.7 9 9% 8.6  ± 0.84 9.8  ± 0.42 10 10% 9.6  ± 0.52 10 Graph Showing the mortality of larvae using Neem plant extract Table 3 Mortality of larvae using different concentration of Tulsi extracts S. No. Different Concentrations of Tulsi Extract Mean No. of larvae Killed 12 hours 24 hours 1 1% 1.8  ± 0.63 3  ± 0.67 2 2% 2.6  ± 0.7 3.6  ± 0.52 3 3% 3.3  ± 0.67 4.4  ± 0.7 4 4% 4.1  ± 0.74 5.3  ± 0.82 5 5% 4.8  ± 0.79 5.8  ± 0.79 6 6% 5.4  ± 0.52 6.7  ± 0.48 7 7% 6.2  ± 0.79 7.4  ± 0.7 8 8% 7  ± 0.67 8.1  ± 0.57 9 9% 7.9  ± 0.57 9.1  ± 0.63 10 10% 8.7  ± 0.67 9.6  ± 0.52 Graph Showing the mortality of larvae using Tulsi plant extract Table showing the comparative mean mortality of the larvae using Tulsi and Neem extracts Different Concentrations Mean No. of larvae Killed in 12 hours Mean No. of larvae Killed in 24 hours Tusli Neem Tulsi Neem 1% 1.8  ± 0.63 2.4  ± 0.52 3  ± 0.67 3.5  ± 0.53 2% 2.6  ± 0.7 3.2  ± 0.63 3.6  ± 0.52 4.3  ± 0.48 3% 3.3  ± 0.67 3.9  ± 0.57 4.4  ± 0.7 5  ± 0.67 4% 4.1  ± 0.74 4.6  ± 0.7 5.3  ± 0.82 5.9  ± 0.74 5% 4.8  ± 0.79 5.3  ± 0.67 5.8  ± 0.79 6.4  ± 0.7 6% 5.4  ± 0.52 5.8  ± 0.42 6.7  ± 0.48 7  ± 0.67 7% 6.2  ± 0.79 6.5  ± 0.85 7.4  ± 0.7 7.5  ± 0.53 8% 7  ± 0.67 7.4  ± 0.52 8.1  ± 0.57 8.6  ± 0.7 9% 7.9  ± 0.57 8.6  ± 0.84 9.1  ± 0.63 9.8  ± 0.42 10% 8.7  ± 0.67 9.6  ± 0.52 9.6  ± 0.52 10 Graph comparing number of larvae killed using both plant extracts in 12 hours Graph comparing number of larvae killed using both plant extracts in 24 hours T Values at Different concentrations of Neem and Tulsi extract Concentration of Neem and Tulsi Calculated t value in 12 hours Calculated t value in 24 hours 1% 2.32 1.85 2% 2.14 3.13 3% 2.16 1.96 4% 1.55 1.72 5% 1.53 1.80 6% 1.89 1.15 7% 0.82 0.36 8% 1.49 1.75 9% 2.18 2.92 10% 3.36 2.43 4. Discussion A t-test was performed for the values obtained for the comparison of the crude extracts. The t-test values for crude Neem and Tulsi extracts are effective if seeing if Neem is significantly more effective than Tulsi in a certain time period. The calculated t value for 1 hour is 3.38. This is higher than the table t value of 2.10. Hence in 1 hour Neem is significantly more effective in killing larvae. In 12 hours the calculated t value is 2.45 and therefore we can draw the same conclusion. However in 24 hours the calculated t value in 1.96 and thus there is no significant difference in the effectiveness of Neem and Tulsi. By this point it is evident that, as far as Hypothesis 1 is concerned, that both Neem and Tulsi are effective in killing mosquito larvae. With regard to the crude extract we can say that in 1 and 12 hour periods, Neem is more significantly more effective but not in 24 hours (Hypothesis 2). T-tests were also performed to compare the significant difference in mortality of Neem and Tulsi extracts at different concentrations. Separate t-tests were performed for 12 hours and 24 hours. As seen in the tables above the t-values are significant in 12 hours for 1%, 2% and 3%. They are significant as at these concentrations the calculated t values are greater than the table t value of 2.10. It is also observed in 9% and 10% concentrations in 12 hours. In 24 hours significance is observed in 2%, 9% and 10%. What these means is that for these concentrations in their respective time periods, Neem is significantly more effective than Tulsi in killing larvae. The main effect that Azadirachta indica has on larvae is the growth regulatory effect. It is because of this property that Neem acts as an excellent natural insecticide. Exposure of culex larvae to sub lethal doses prolongs the larval development and causes reduced pupal weight and oviposition. Neem works by intervening at several stages of the insects life. The ingredients present in Neem are approximately the same shape and structure of vital hormones for the insects. The larvae absorb these Neem compounds as if they were real hormones which blocks their endocrine systems. This leaves the insects so sonfused in brain and body that they cease to reproduce and thus the population plummets. Tulsi extract exhibits high mortality, especially during the molting process. The molting of larvae takes place under the influence of the ventral nerve cord neurosecretory cells. These cells release the tanning hormone. The extract may have an inhibiting effect on such cells. They may also act on epidermal cells that produce enzymes necessary for the circular oxidation process. Both plant extracts affect reproduction and inhibit the emergence of adult mosquitoes from their larvae. They also decrease the feeding time for larvae and cause less food to be ingested. This has been noted to cause a fall in the carbohydrate levels of the larvae. A study noted that the extracts cause the amount of DNA and RNA in the larvae to fall thus suggesting that the extracts may affect nucleic acid synthesis. The feeding in the larvae may have decreased due to indigestion caused by the plant extracts as they inhibit metabolic processes. [9] Both Ocimum sanctum and Azadirachta indica are available easily and in large quantities. They do not require professional handling, are inexpensive and safe which makes them very valuable as pesticides. Additionally Tulsi has properties that enable it to disinfect water. The extracts could help replace harmful pesticides used such as DDT as they are safe for non target animals and do not pose residue problems but are still effective in killing larvae and suppressing the adult mosquito population. In conclusion further effort should be taken to produce bio-pesticides from Neem or Tulsi as well as research to find other plants products that may be more ideal. UV rays may affect the Neem and Tulsi extracts thus making them ineffective so research should be done in order to find plant products that do not degrade in the presence of sunlight thus making them completely versatile. 5. Summary * The findings have important implications in the practical control of mosquito larvae, especially, in a polluted aquatic environment. * Ocimum sanctum and Azadirachta indica are the two plants out of which the extracts were prepared. * Solutions of concentrations varying from 1% to 10% were prepared from the stock solution for each plant. * Each concentration was tested on 10 larvae. 10 trials were undertaken and the results were noted. * Both plants were deemed effective as far as larval mortality in concerned. Neem extract had a slightly higher mortality rate. 6. Bibliography (Singh et al. 2000, 2004). Pest management in sericulture (2000), Properties and potential of natural pesticide against sericulture pests. Publ. Zool. Soc. India. pp. 200-206 (Singh and Saratchandra, 2002). An Integrated approach in pest management in sericulture, Int. J . Indust. Entomol. 5, 141-151 (Baskaran and Narayanswamy, 1995) Traditional pest control. Caterpillar Publications. Tamil Nadu, India. (Casida, 1983). Development of synthetic insectide from natu ral products. Case History of pyrethroids from pyrethrins. (Schmutterer, 1990). Properties and potential of natural pesticide from Neem tree. Ann. Re

Dostoevsky’s influence on Bryusov

The aim of the paper is to see the line of Dostoevsky’s influence on the creative work of Valeriy Bryusov through his prose story ‘The Republic of the Southern Cross’ originally published in 1907. It is stated, that the main influence, through which ‘The Republic of the Southern Cross’ may be seen from the viewpoint of Dostoevsky’s creative work is the influence of his Raskolnikov on the way Bryusov’s story has been written. Similar analogies can be traced through the comparison of the Dostoevsky’s works and statement that ‘The Republic of the Southern Cross’ is antiutopia.(Jackson, 1958) However, to clearly see these similarities it is necessary to analyze the story closer. The Republic of the Southern Cross remains to be the most popular prose work of Bryusov. He has been able to write ‘realistic fantastic story’, which has immediately called critics for te comparisons with the Dostoevsky’s works . The dead end of the people’s lives which Bryusov was able to depict is easily seen in Dostoevsky’s ‘Crime and Punishment’. ‘It must be said that this democratic exterior concealed the purely autocratic tyrannyof the shareholders and directors of a former Trust. Giving up to others the places of deputies in the Chamber they inevitably brought in their own candidates as directors of the factories. In the hands of the Board of Directors was concentrated the economic life of the country. The directors received all the orders and assigned them to the various factories for fulfilment; they purchased the materials and the machines for the work; they managed the whole business of the factories. Through their hands passed immense sums of money, to be reckoned in milliards’. (Bryusov, 1907)The influence of Dostoevsky was seen through the fact that antiutopic scenes in Bryusov are based on the Raskolnikov’s dream in ‘Crime and Punishmentâ €™. (Jackson 1958) However, it is also possible that when writing his Republic Bryusov was also using the principal themes of the ‘Apocalypses’. The initial situation of the subject who has sinned is very similar to that of Raskolnikov, his loneliness and sadness which he does not really realize himself. From the citation above, it is easy to understand why people started to suffer from the Disease of Contradiction.The endlessness of the silly behaviors of people in the republic has led to the terrible catastrophe, and only several men try to resist to this chaos. ‘A train conductor on the metropolitan railway, instead of receiving money from the passengers, himself pays them. A policeman, whose duty it was to regulate the traffic, confuses it all day long. A visitor to a gallery, walking from room to room, turns all the pictures with their faces to the wall. A newspaper page of proof, being corrected by the hand of a reader already overtaken by the disease, i s printed next morning full of the most amusing absurdities.At a concert, a sick violinist suddenly interrupts the harmonious efforts of the orchestra with the most dreadful dissonances. A whole long series of such happenings gave plenty of scope for the wits of local journalists’. (Bryusov, 1907) Isn’t it similar to the way Raskolnikov was seen to behave after he has committed the crime? The fall of morality in the society is also in the line with moral fall of Rasolnikov. (Jackson, 1973) Bryusov makes special stress on the way morality disappears and people become animals.Morality was seen as the thin surface which has been easily breached despite the fact that it had been held with people through millennia. However, the story is as if the reverse reflection of Dostoevsky’s ‘Crime and Punishment’ – if he has been able to show the fall of morality in Raskolnikov at the beginning of his book, making it the center of his revival, spiritual and moral tortures, as well as his understanding of the seriousness of his crime, the story written by Bryusov makes the reverse action and the moral fall is shown at the end of the story, with the life of the Republic making it possible step by step.These are the characteristic features of antiutopia. It means, that the story shows the consequences of utopia, works with complex social models and suggests possible development of the certain social events. Dostoevsky didn’t do this in his story; he has not suggested any other versions of Raskolnikov’s crime. The lines of Dostoevsky’s ‘Notes from the Underground’ are even more clearly seen through reading Bryusov’s The Republic.Dostoevsky’s Notes have been written as the means for Dostoevsky to show that he had been against any strict rationalism in the human life, and it was probably his biggest fear that once human lives would be ruled by rationality, about which we have read in The Repub lic. The symbols of this fear included by Dostoevsky into his work are mathematical tables and piano key. For example, if the analogy is made between the anthill and the ants, according to Dostoevsky, the individuality is lost when all ants work towards one and the same objective, especially when the work is standardized, as everything has been standardized in The Republic.(Brians, 1995) Mathematical tables appeared to be the way to investigate the feelings of people in the notes, but it is understandable that the fears and other emotional states of people cannot be mapped out, and the result of this mapping out was described by Bryusov. Dostoevsky as a writer was against discussing and explaining the behavior of people in scientific terms and means. This behavior he has been explaining through other deeper meanings, which are also found in Crime and Punishment.(Jackson, 1973) ‘The greatest example of science and modernity that Dostoevsky presents to the reader is the Crystal Palace. The Crystal Palace was a structure built in 1851 in London. It was the first modern building. It was made entirely out of glass and iron. This palace was supposed to be as good as it gets. It was utopianism brought out into real life. To Dostoevsky it represented reason, science and logic’. (Brians, 1995) The parallel with Bryusov’s Republic is so vivid that cannot be denied:‘Because of the severity of the climate, an impenetrable and opaque roof had been built over the town, with powerful ventilators for a constant change of air. These localities of the globe have but one day in six months, and one long night also of six months, but the streets of Zvezdny were always lighted by a bright and even light. In the same way in all seasons of the year the temperature of the streets was kept at one and the same height’. (Bryusov, 1907)In Dostoevsky’s prose people are seen to be submitted to an organized living through the strict standards which are uniform for everyone without an exception; as far as people were working in one environment towards the same goal, individualism was absent, as well as it was absent in the Republic. Conclusion The influence of Dostoevsky on the creative work of Bryusov is clear, and the Republic of Southern Cross is the brightest example to see this influence. It has been analyzed through the two essential Dostoevsky’s works – ‘Crime and Punishment’ and ‘Notes from Underground’.The reason for choosing these two stories lies in the fact, that first of all, The Notes and The Republic are often criticized for being similar in their literary implications and backgrounds, and the work has proved that the principal motives are similar in both; as for Crime and Punishment, I guess it was a good example to show the moral fall of people, and how fast it can be to turn people into beasts, and though the development of the events and moral fall are opposite in both wor ks, it has been interesting to trace analogies in them.Works cited Brians, Paul. Study Guide: Notes from the Underground. Washington State University, 1995 Bryusov. V. The Republic of the Southern Cross. 1907. Available at http://gaslight. mtroyal. ab. ca/repsouth. htm (accessed 03 March 2007) Jackson, R. L. Twentieth Century Interpretations of Crime and Punishment. Prentice Hall Trade, 1973 Jackson, R. L. Dostoevsky’s Underground Man in Russian Literature. Mouton, Hague, 1958.

History of the Olympic Games

The modern Olympic movement has been shaped by many differentiating factors over the years. It has been altered by social, political, and economic factors. More specifically, warring times, changes to social structures, and economic activity that varies by country have been the overall leading factors that have shaped the Olympics over the years. The Olympics have shown over the decades that they can be affected by political conflict. However, it seems that this is the point of the Olympics, to illustrate national pride, by competition.Bloodshed should not be the way for pride of one’s country to be shown, but it should be shown through competition, in the words of the founder of the modern Olympic movement, Pierre de Coubertin(1). The games have been used as a weapon for denouncing a country’s sportsmanship, such as in 1956 when Arnold Lunn, a British Olympic team official accused the Nazis of cheating in the 1936 Olympic games that were held in Germany. He went on to allege that the competitors of Germany went onto the course while it was closed to athletes.Though the fact that they were trying so hard to practice, could be an example of the importance placed on the games at the time before war period. This is implied by the statement by Arnold Lunn that victory was the only thing that mattered to the Nazis, and how they achieved it did not matter as long as they did(3). The use of the Olympics to show off one’s country was further demonstrated during the Cold War, when the United States and the Soviet Union were itching to outdo one another.Bob Matthias gives insight through an interview into the United State’s yearning to win over Russia. The competitor told of the spirit of winning throughout the team, even in the athletes that were sure to win for the United States(4). This is a stark contrast to an information guide provided by the Soviet Union regarding the olympics being held in Moscow that year. It tells of seeking peace wi th the U. S. , and how the Olympics were a beacon for social progress and democracy(6). This resulted in the U. S.boycotting the Olympics, due to the obvious bias in the information. Ali Kabir, finally, told of how the rise and fall of his nation’s hockey team reflects the lack of unity in his own country, even going as far as stating that it’s players are clueless and have tarnished Pakistan’s name(10). This further demonstrates how the Olympic Games reflect political events at the time they are being held. Not only do the Olympic games make a habit of displaying the events of the world through it’s ‘friendly’ competitions, but it also lets economic factors manifest in it’s events.Ryotaro Azuma, mayor of Tokyo, spoke in an interview in 1972 regarding the 1964 Olympic games held in Japan. He told of how his country finally had a chance to get out of the losing spirit after World War II and rise as a world trade power. The Olympic Games in this case, were used to boost a country’s economy and wealth as well come back as a leading power(5). A Japanese newspaper editorial in 1988 commented about the use of industrial powers by South Korea in that year’s Olympic games, or lack thereof.It comments negatively on the fact that South Korea did not have the funding to set up the games as well as display it’s industrial and economic power to the world, implying that no matter the medals one, the industrial power by the U. S. , Japan, and other countries will make a lot of profit and leave a memorable impression on the world while South Korea will not(7). The International Olympic Committee provided statistics lending insight into the fees provided into Olympic events, showing an expected trend.In 1980, it is useful to know that the U. S. and Soviet Union were locked in the Cold War, and as stated previously, the U. S. refused to come to the Olympic Games held in Moscow as well as Russia refusing to att end the one in Los Angeles. The shockingly low fees paid to have viewing and advertising rights to the games held in Moscow reflects the war. Many countries boycotted the Olympics that year, so the severely low amount of fees paid further demonstrates this tense time in during the 20th century.However, the dramatic increase in the fees paid to broadcast Atlanta’s games illustrates the time of peace after the Cold War ended, with over 800 million dollars being given to broadcast the games(9). Finally, the Olympic games are altered by the diverse and changing social structures in the world. For instance, in 1908 a photograph of British competitor Sybil Newall shooting her bow was found on newspapers across England(2). Whether this photograph was staged to sell newspapers or not, it cannot be denied that this photograph indicates the beginning of women’s movement, which was obviously an important issue during this time in the world.With more leniency being given to women during this time, they were eventually being allowed to compete in the competitive events, though only 2% of the athletes were women. This factor also continues to show during the 1992 games held in Spain, where by then 29% of women were competing. Hassiba Boulmerka was an Algerian competitor during this time and spoke in an interview about her critics, and how being the first Algerian to win an Olympic title did not depend on her gender, but simply on her strength in her mind and in body.Boulmerka was heavily criticized by Muslim groups in Algeria for wearing shorts as she ran in the events. Despite this, the games illustrated the decreasing requirements for dresses and increasing requests for appropriate attire, no matter what gender the competitor identifies as. A helpful addition to analyzing the Olympic games would be an article reflecting the point of view of a German athlete during the 1936 games being held in Germany. They could explain why the competitors went onto the cour ses to practice while they closed, or if they did at all.He or she could balance the point of view by pointing out that they did not cheat, and that they simply were practicing and either did not know the rules or were just doing what they thought would be okay. Another helpful article would be to add on to the statistics provided by the International Olympic Committee by showing how many countries that competed versus the countries that actually paid for broadcasting rights, especially during the 1980’s games.This would show whether there is an actual correlation between the lack of countries participating and the lack of money being put into the broadcasting rights of the games. The Olympic games have been shown to be altered and influenced by the social, economic, and political events happening all around it. It seems to be the central point of tension and friendly competition every four years. It was intended to be that way, reflecting the world’s ever changing vie ws on life and each other.

How to Express Exclamations in French

Exclamations are words or phrases that express a desire, an order, or a strong emotion. There are various French grammatical structures that can be used as true exclamations. All of them end in an exclamation point, and there is always a space between the last word and the exclamation mark, as there is for several other French punctuation marks. The exclamation mark is a grammatical end mark that occurs often in French, whether the sentence or phrase is a true exclamation or not. It is, thus, in many instances a softer mark than in English. Exclamation points are often added even if speakers are just a little agitated or are raising their voice even slightly; the mark doesnt have to mean that they are truly exclaiming or declaring something.   By the way, Merriam-Webster defines an exclamation as: a sharp or sudden utterancea vehement expression of protest or complaint And Larousse defines the French equivalent verb  sexclamer,  as to cry out; for example, sexclamer sur la beautà © de quelque chose  (to cry out in admiration over the beauty of something).   Here are some French grammatical structures that can be used to express exclamations where urgency or a heightened emotional state is implicit. French Imperative The imperative expresses an order, hope, or wish, as in: Viens avec nous.   Come with us. The imperative can also express urgency or an extreme emotional state, as in: Aidez-moi !  Ã‚  Help me! Que Subjunctive Que followed by the subjunctive creates a third person command or wish: Quelle finisse avant midi  !   I hope shes done by noon!Quil me laisse tranquille  !   I wish hed just leave me alone! Exclamative Adjective The exclamative adjective quel is used to emphasize nouns, as in: Quelle bonne idà ©e  !   What a good idea!Quel dà ©sastre  !   What a disaster!Quelle loyautà © il a montrà ©e  !   What loyalty he showed! Exclamative Adverbs Exclamative adverbs like que or comme add emphasis to statements, as in: Que cest dà ©licieux  !   Its so delicious!Comme il est beau  !   He is so handsome!Quest-ce quelle est mignonne!   She sure is cute! The Conjunction Mais The conjunction mais  (but) can be used to emphasize a word, phrase, or statement, like this: Tu viens avec nous  ?   Are you coming with us?Mais oui  !   Why yes!Il veut nous aider.   He wants to help us.Mais bien sà »r  !   But of course!Mais je te jure que cest vrai  !   But I swear its true! Interjections Just about any French word can be an exclamation if it stands alone as an interjection, such as : Voleur  !   Thief!Silence  !   Quiet! Quoi and comment, when  used as interjections,  express shock and disbelief, as in: Quoi  ! Tu as laissà © tomber cent euros  ?   What! You dropped a hundred euros?Comment  ! Il a perdu son emploi  ?   What! He lost his job? Indirect Exclamations All of the above are called direct exclamations  because the speaker is exclaiming his or her feelings of shock, disbelief, or amazement. Indirect exclamations, in which the speaker is explaining rather than exclaiming, differ from direct exclamations in three ways: They occur in sub-clauses, do not have an exclamation point, and require the same grammatical changes as indirect speech: Quelle loyautà © il a montrà ©e  ! Je sais quelle loyautà © il a montrà ©e.What loyalty he showed! I know what loyalty he showed.Comme cest dà ©licieux  ! Jai dit comme cà ©tait dà ©licieux.Its delicious! I said it was delicious. In addition, the exclamative adverbs que, ce que, and quest-ce que in direct exclamations always change to comme or combien in indirect exclamations: Quest-ce cest joli  ! Il a dit comme cà ©tait joli.Its so pretty! He said how pretty it was.Que dargent tu as gaspillà ©Ã‚  ! Je sais combien dargent tu as gaspillà ©.Youve wasted so much money! I know how much money youve wasted.