Effect Of Tulsi And Neem Extract On Mosquito Biology

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The consequence of Neem and Tulsi on mosquito larvae. The undertaking is aimed at happening natural pesticides or bio-pesticides that efficaciously control the mosquito population by killing mosquito larvae. They could be used as options to the current pesticides used that have inauspicious effects on the environment and other species besides the mark plague. Mosquitos are hosts for a really big figure of diseases and hence maintaining larvae under control and forbiding the outgrowth of grownup mosquitoes is indispensable.

Two works infusions have been tested ; Neem and Tulsi. The initial hypothesis was that both infusions would hold some consequence on the larval development and cause mortality in the larvae due to the belongingss of both workss. The secondary initial hypothesis was that Neem pull out would be significantly more effectual in killing the larvae than Tulsi at the same per centum. Concentrations of 1 % to 10 % of each infusion were prepared and 10 tests each performed with 10 larvae were undertaken.

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The samples were checked on after 12 hours and one time once more after 24 hours and the figure of larvae killed in each instance was recorded. The consequences were conclusive and both infusions were really effectual at killing larvae at 10 % with Neem killing an norm of 10 larvae out of 10 and Tulsi 9.6 A± 0.52.

However t-values showed that the initial hypothesis saying that Neem would be more effectual at all concentrations was wrong and merely 2 % , 9 % and 10 % were significantly more effectual in 24 hours with t values of 3.13, 2.92 and 2.43 severally ( & gt ; table value of 2.10 ) . This means that in 2 % , 9 % and 10 % concentrations, Neem should be used alternatively of Tulsi as it is significantly better. This is all really exciting as environmentally safer pesticides can be developed from these two works infusions.

The conservative pesticides are augmented to battle complicated plague jobs in mosquitoes. In human wellness during the past few decennaries these pesticides played an of import function in the suppression of diseases caused by mosquitoes either by demobilizing or killing these mosquitoes. Subsequently on when these pesticides are acquiring accumulated in the environment proved to be risky to the environment and world.

Frequent application of man-made organic insect powders resulted into pest opposition and eruption. Most of the insecticidal compound falls within four chief categories viz. organochlorides, organophosphates, carbamates and pyrethroids. Out of these the major categories of insect powders, the insect powders used in present state of affairs are organophosphates and carbamates. There are jobs of pesticides opposition and negative impacts on non-target beings including adult male and the environment.

Environment jobs due to the insect powders and pesticides such as devastation of good beings, non-target plague, some of the pesticide residues in the host works ensuing in stunted grow or killing other beings have come to an terminal. This work is fundamentally taken up by some of the herbal workss. These herbal workss possess some of the active ingredients which are eco-friendly but at the same time have a terrible consequence on the mosquito populations.

Medicative workss are the most promising beginning and under extended trails for their biological activity against assorted mosquito larvae. During the last 10 to 15 old ages, involvement in botanical insect powders has increased to look for permutations for man-made insect powders with those based on of course happening substances. The usage of botanicals in pest direction is non merely utile for suppression of pest population but besides helps to keep the sound ecological balance.

The groups of works possessing insecticidal substances are tremendous. More than 2400 species of the workss in India possess insecticidal properties3. In the center of the seventeenth century, most of the economically of import natural works compounds obtained from the workss like nim tree, tulsi, adathoda, chrysanthemum, turmeric, garlic, tridax etc. are used in commercial insect control. Despite the comparative safety of the well-known botanical insect powders, most of these substances have their drawback impeding large-scale application. The chemicals obtained from these workss are unstable in the sunshine and are quickly metabolized therefore restricting their authority and application.

Botanical insecticides break down readily in dirt and are non stored in animate being and works tissue. Often their effects are non as long enduring as those of man-made insect powders and some of these merchandises may be really hard to happen. The works parts used for extraction or check were the foliages, roots, tubers, fruits, seeds, flowers, the whole works, bark, sap, cods and wood. The most normally utilised parts were the foliages, roots. The works households Asteraceae, Fabaceae and Euphorbiaceae contain most of the insecticidal works species reported.

Neem is possibly the most good 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 household and is a botanical cousin of mahogany. Neem is really difficult and virile. Neem is particularly utile due to its climatic tolerance that allows it to be grown all over the universe though it is normally found in tropical parts.

It has insecticidal, antifeedant, growing regulation and development-modifying belongingss and has belongingss that make it attractive in insect control. It reduces fruitfulness and length of service every bit good as increased development clip of immature insects. On insects it has been shown to move as a growing retardent and cause moult upsets, alteration of behaviour and morphogenetic defects. Mosquito control is indispensable as they act as bearers for malaria, filariasis and a host of other diseases every bit good as being a nuisance. There is a high demand for a less environmentally harmful insecticide as the 1s presently used have high neurotoxic effects.

Recent surveies have besides demonstrated neem-induced effects on vitellogenesis and terrible devolution of follicle cells during oogenesis in mosquitoes. It besides has several medical belongingss such as a remedy blood morbidity, bilious afflictions, rubing, skin ulcers, firing esthesiss and pthysis. It is besides an effectual remedy against tinea, eczema and itchs. In English the tree is known as neem and attains a maximal tallness of 40 to 50 meters.

Tulsi is an aromatic works in the Lamiaceae household. Tulsi has been used for 1000s of old ages in Ayurveda due to its diverse healing belongingss. Tulsi ‘s infusions are used in ayurvedic redresss for common colds, concerns, tummy upsets, redness, bosom disease, assorted signifiers of toxic condition, and malaria. Traditionally, tulsi is taken in many signifiers: as herbal tea, dried pulverization, fresh foliage, or assorted with ghee. Essential oil extracted from Karpoora Tulsi is largely used for medicative intents and in herbal cosmetics, and is widely used in skin readyings due to its anti-bacterial activity. For centuries, the dried foliages of Tulsi have been mixed with stored grains to drive insects.

These workss in harmonious integrating with other safe methods of pest control like biological control can supply eco-friendly and economically feasible solutions for plague jobs in close hereafter.

Plants bring forthing the compounds holding insect growing regulators ( IGR ) , feeding hindrances, repellants and confusants activities are known by the husbandman because most of the clip they grow in the same general country. Some of these merchandises may be these merchandises act really rapidly suppressing insect feeding even though long term they do non do insect decease. Since most of these merchandises have a tummy action and are quickly decomposed they may be more selective to insect plagues and less aggressive with natural enemies. Most of these compounds are non phytotoxic and have rapid action and low toxicity to mammals and workss. Resistance to these compounds is non developed every bit rapidly as with man-made insect powders.

Most of these merchandises are non genuinely insecticides since many are simply insect hindrances and their consequence is slow. They are quickly degraded by UV light so that their residuary action is short and breakdown is rapid, necessitating more precise timing of and/or more frequent application. Not all works insect powders are less toxic to other animate beings than the man-made 1s. They are non needfully available and sometimes cost is more. Most of them have no established residue tolerances and there is deficiency of trial informations and sometimes deficiency of province enrollment of some stuffs. There are no legal enrollments set uping their usage. Not all recommendations followed by agriculturists have been scientifically verified. The above statements are altered if you find anything that can be added or deleted you can make it.

Insects adapt themselves to aquatic home grounds inspite of their tellurian beginning. The aquatic and semi-aquatic insects are singular for their diverseness of signifiers, reflecting version to a broad assortment of niches such as salt H2O pools, saline pools, hot springs, high mountain lakes, big rivers, impermanent and lasting pools.

Mosquitos are known as vectors of the pathogens doing human diseases. They belong to the order Diptera ; the true flies. Like all flies they have two wings but unlike other flies they have graduated tables and the females have sucking proboscis. There are over 2500 species of mosquitoes. Culex mosquitoes are known to be painful and relentless biters and are a nuisance.

The ground why I chose this subject is because the pesticides that are presently used in pest control contain chemicals that have diverse side effects on the environment and organisms other than the mark plague. I decided to utilize natural substances found in nature and see if they would work as a signifier of pest control alternatively. I have used two infusions ; Neem and Tulsi, in order to see which one was more effectual in killing these mosquitoes. Neem, Tulsi and eucalyptus have been used as they are prevailing in the tropical and sub-tropical states of Africa and Asia with a big mosquito population and there have been important chances of being used as an insect powder on a commercial graduated table due to their utile belongingss.

In early literature mentioned above it was noted that the mosquitoes suppress both impermanent and fresh H2O dead organic structures and they are found in copiousness doing nuisance to the human population. The purpose of the present survey was undertaken on the undermentioned facets

  • To find the figure of Culex larvae killed in 12 hours and 24 hours utilizing different works infusions like Neem and Tulsi in rough signifier.
  • To find the figure of Culex larvae killed in 12 hours and 24 hours by Neem and Tulsi under assorted concentrations ( 1 % -10 % ) .
  • To find the statistical analysis t – trials were performed.

For the present survey, the larvae of Culex mosquitoes were used throughout the probe. These larvae were chosen because they were most abundant in the H2O organic structures which are really active fast writhing motion. The Culex larvae were collected from dead H2O organic structures at Varthur Lake in Bangalore ( fig.1 ) utilizing a manus cyberspace. They were transported in fictile pails incorporating clean H2O to the lab. Larvae were categorized based on their size as big and little. The big sized Culex larvae were approximately 0.7 centimeters and the little sized Culex larvae measured about 0.2cm in length. For the present survey I have used merely big sized larvae ( 3rd and 4th instars phase ) .

I collected neem foliages from my school campus. Merely immature foliages were collected and dried in the absence of sunshine in the fly-by-night part. The complete method of fixing 10 % stock solution of this works infusion is mentioned below. 10 gms of dried immature foliages were so grinded utilizing howitzer and pestle along with methyl alcohol and dried. Then add 100 milliliter of distilled H2O to do out 10 % stock solution.

Then the 10 % neem stock solution was decanted after centrifugation. Now from this 10 % stock solution different concentration solutions in per centum were prepared [ runing from 1 % – 10 % ] i.e. , 10ml of 10 % stock solution in 90ml of distilled H2O gives 1 % , 20ml of 10 % stock solution in 80ml of distilled H2O will give 2 % , 30ml of 10 % stock solution in 70ml of distilled H2O will give 3 % , 40ml of 10 % stock solution in 60ml of distilled H2O will give 4 % , 50ml of 10 % stock solution in 50ml of distilled H2O will give 5 % , 60ml of 10 % stock solution in 40ml of distilled H2O will give 6 % , 70ml of 10 % stock solution in 30ml of distilled H2O will give 7 % , 80ml of 10 % stock solution in 20ml of distilled H2O will give 8 % , 90ml of 10 % stock solution in 10ml of distilled H2O will give 9 % , and for 10 % the stock solution itself was used.

I collected Tulsi foliages from my school campus. Merely immature foliages were collected and dried in the absence of sunshine in the fly-by-night part. The complete method of fixing 10 % stock solution and the different concentration of this works extracts in per centum was done by same method as mentioned above in Neem.

Mortality of larvae utilizing petroleum works infusions:

  • The big sized Culex larvae were taken in the petridishes.
  • 5 milliliter of petroleum works infusions of nim tree and tulsi were taken in the different trial tubings.
  • 10 larvae were introduced in each trial tubing at the same clip.
  • Ten trails were carried out for the two different works infusion.
  • The figure of larvae killed was recorded for 1hr, 12hr and 24 hour.
  • Larvae were feed with Canis familiaris biscuit pulverization.
  • Comparative analysis was carried out diagrammatically between the two works infusions at different clip period.

Mortality of larvae utilizing different concentration of works infusions:

  • The big sized Culex larvae were collected and separated in the petri dishes.
  • 5 milliliter of 1 % Neem infusion was pipetted in the trial tubing utilizing a calibrated pipette.
  • 10 Culex larvae were introduced and the clip was noted.
  • Ten tests were carried out at the same clip for different concentration.
  • The larval mortality was recorded for 12 hours and 24 hours.
  • The same process was followed for different concentrations [ 2 % , 3 % , 4 % , 5 % , 6 % , 7 % , 8 % , 9 % & A ; 10 % ] of the Neem infusion.
  • During this experiment the larvae was feed with Canis familiaris biscuits in powdery signifier.
  • The above mentioned process was besides carried out utilizing Tulsi works infusion.
  • A comparative survey of larval mortality was made by utilizing these two workss extract on the Culex mosquito larvae.
  • The per centum of mortality ( which will give us an indicant of the effectivity of the infusion ) will be calculated utilizing the undermentioned expression.
  • Percentage of mortality = X 100


  • Dependent variable- Number of larvae killed
  • Independent variable-Different concentration of neem infusion and tulsi infusion, different clip period [ 1hr, 12 hour, 24 hour ]
  • Controlled variable-Number of larvae, Volume of H2O, Temperature, nutrient


The Culex larvae were exposed to different works infusions in rough signifier to analyze the mortality rate. The figure of Culex larvae killed was recorded after 1 hr, 12 hours and 24 hours individually.

In one hr the average figure of larvae killed by Neem was 4.9A±0.74 and for Tulsi it was 3.5A±1.08. As clip progresses the difference in effectiveness becomes less and the two infusions are about equal. The rough infusion of Neem was more effectual than Tulsi in one hr continuance. At 12 hours the average figure of mosquitoes killed were 9.2A±1.14 and 8A±1.05 severally. At 24 hours the Neem and Tulsi extracts showed about the same degree of effectivity with average values of 10 and 9.7A±0.48 severally.

The rough signifier of Neem infusion was significantly more effectual than Tulsi in killing the Culex larvae in 1 hr and 12 hours. However in 24 hours there is no important difference in the effectivity of Neem and Tulsi works infusions.

The mortality of the larvae utilizing different concentrations of Neem infusion was recorded. At 1 % concentration the average figure of larvae killed was noted to be 2.4 A± 0.52 in 12 hours and 3.5 A± 0.53 in 24 hours. At 10 % concentration the highest mortality rate was recorded as 9.6 A± 0.52 and 10 for 12 hours and 24 hours severally. As the concentration of the Neem infusion increased, the mortality of the larvae besides steadily increased.

The mortality of the mosquitoes for Tulsi infusion was recorded in the same manner as Neem. At 1 % concentration the average figure of larvae killed was noted to be 1.8 A± 0.63 in 12 hours and 3 A± 0.67 in 24 hours. At 10 % concentration the highest mortality rate was recorded as 8.7 A± 0.67 and 9.6 A± 0.52 for 12 hours and 24 hours severally. As the concentration of the Tulsi infusion increased, the mortality of the larvae besides steadily increased.


A t-test was performed for the values obtained for the comparing of the petroleum infusions. The t-test values for petroleum Neem and Tulsi infusions are effectual if seeing if Neem is significantly more effectual than Tulsi in a certain clip period. The deliberate T value for 1 hr is 3.38. This is higher than the tabular array t value of 2.10. Hence in 1 hr Neem is significantly more effectual in killing larvae. In 12 hours the deliberate T value is 2.45 and hence we can pull the same decision.

However in 24 hours the deliberate T value in 1.96 and therefore there is no important difference in the effectivity of Neem and Tulsi. By this point it is apparent that, every bit far as Hypothesis 1 is concerned, that both Neem and Tulsi are effectual in killing mosquito larvae. With respect to the petroleum extract we can state that in 1 and 12 hr periods, Neem is more significantly more effectual but non in 24 hours. T-tests were besides performed to compare the important difference in mortality of Neem and Tulsi infusions at different concentrations. Separate t-tests were performed for 12 hours and 24 hours.

As seen in the tabular arraies above the t-values are important in 12 hours for 1 % , 2 % and 3 % . They are important as at these concentrations the deliberate T values are greater than the tabular array t value of 2.10. It is besides 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 several clip periods, Neem is significantly more effectual than Tulsi in killing larvae.

The chief consequence that Azadirachta indica has on larvae is the growing regulative consequence. It is because of this belongings that Neem acts as an first-class natural insect powder. Exposure of culex larvae to stand in deadly doses prolongs the larval development and causes reduced pupal weight and oviposition. Neem works by step ining at several phases of the insect ‘s life. The ingredients present in Neem are about the same form and construction of critical endocrines for the insects. The larvae absorb these Neem compounds as if they were existent endocrines which blocks their endocrinal systems. This leaves the insects so sonfused in encephalon and organic structure that they cease to reproduce and therefore the population plumb bobs.

Tulsi infusion exhibits high mortality, particularly during the moult procedure. The moult of larvae takes topographic point under the influence of the ventral nervus cord neurosecretory cells. These cells release the tanning endocrine. The infusion may hold an inhibiting consequence on such cells. They may besides move on cuticular cells that produce enzymes necessary for the round oxidization procedure.

Both works extracts affect reproduction and suppress the outgrowth of grownup mosquitoes from their larvae. They besides decrease the eating clip for larvae and cause less nutrient to be ingested. This has been noted to do a autumn in the saccharide degrees of the larvae. A survey noted that the infusions cause the sum of DNA and RNA in the larvae to fall therefore proposing that the infusions may impact nucleic acerb synthesis. The eating in the larvae may hold decreased due to dyspepsia caused by the works extracts as they inhibit metabolic procedures.

Both Ocimum sanctum and Azadirachta indica are available easy and in big measures. They do non necessitate professional handling, are cheap and safe which makes them really valuable as pesticides. Additionally Tulsi has belongingss that enable it to disinfect H2O. The infusions could assist replace harmful pesticides used such every bit DDT as they are safe for non mark animate beings and do non present residue jobs but are still effectual in killing larvae and stamp downing the grownup mosquito population.

In decision farther attempt should be taken to bring forth bio-pesticides from Neem or Tulsi every bit good as research to happen other workss merchandises that may be more ideal. UV rays may impact the Neem and Tulsi extracts therefore doing them uneffective so research should be done in order to happen works merchandises that do non degrade in the presence of sunlight therefore doing them wholly versatile.


  • The findings have of import deductions in the practical control of mosquito larvae, particularly, in a contaminated aquatic environment.
  • Ocimum sanctum and Azadirachta indica are the two workss out of which the infusions were prepared.
  • Solutions of concentrations changing from 1 % to 10 % were prepared from the stock solution for each works.
  • Each concentration was tested on 10 larvae. 10 tests were undertaken and the consequences were noted.
  • Both workss were deemed effectual every bit far as larval mortality in concerned. Neem infusion had a somewhat higher mortality rate.


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