BACKGROUND OF THE INVENTION The search for a healthier life is causing human beings to try to find natural substances capable of controlling plagues, either in agriculture or in urban life. Thus, they are using chemicals found in plants; these substances are products of primary and secondary metabolism. The first group comprises the substances that are essential to the plant and that are formed in the photosynthetic process. In the second group are comprised the substances mainly involved in the defense of the organism against predators or pathogenic microorganisms and in the reproduction process, attracting pollinators. Such substances, named active principles or secondary compounds, are essential or natural oils, resins, alkaloids and flavonoids (CRUZ, M. E. S.; NOZAKI, M. H. and BATISTA, M. A.

PLANTAS MEDICINAIS E ALELOPATIA-Medicinal Plants and Alelopathy).

The chemical groups present in the commercially sold insecticides are the organophosphorates, carbamates, organochlorines and pyrethroids, being this last group structurally similar to the pyrethrine found in the flowers of the Chrysanthemum sp. The organophosphorates, such as diclorvos, and the carbamates, such as propoxur, are classified as highly toxic, belonging to class I, according to US EPA.

The organochlorines, such as DDT (di-chloro di-phenyl trichloroethane) are classified as moderately toxic and WO 2005/034631 PCT/BR2004/000191 belong to class II, according to EPA. The pyrethroids, such as permetrine and aletrine are classified as moderately toxic and belong to class II, according to EPA.

The organophosphorates and carbamates have as their 5 toxic action mechanism the inhibition of the enzyme acetylcholinesterase. This enzyme is present in the nervous synapses and in the motor plate. Its function is to hydrolyze the acetylcholine neurotransmitter. In cholinergic nerves, acetylcholine is responsible for 10 transmitting the nervous stimulus, and, once it has provoked the desired response, it should be removed to avoid repeated and uncontrolled responses after a single stimulus. Thus, if the acetylcholinesterase is inhibited, there will be an acetylcholine accumulation, resulting in 15 widespread muscular weakness, lung edema, coma and cardiac arrest.

The toxic action mechanism of the organochlorinated, such as DDT, is related to Na+K+ ATPase enzyme inhibition.

This inhibition leads to the alteration of sodium and 20 potassium ions transport through the membrane, having no interruption of the potential action, resulting in shudders, convulsions and breathing arrest. DDT is still used in tropical countries like Brazil, but it has been banned from the USA since 1972, mainly for being highly 25 persistent in the environment, with a slow degradation process and a half life varying from 2 to 15 years. The pyrethroids act by membrane depolarization, by calcium transport alteration as a consequence of Ca2+ ATPase inhibition, which can result in fasciculations, convulsive 30 attacks and coma.

Based on what has been previously exposed, the demand for an effective all-natural larvicide, unharmful to human health is evident.

Orange oil is a by-product of the orange processing in which D-limolene [1-methyl-4- (l-methylethenyl) cyclohexene] is found, and it can be extracted through vacuum distillation. D-limonene is the main component of the orange oil (90-95%), and it is 100% biodegradable. This substance has different applications in the internal and external market, including the production of chemical products and solvents, aromas and fragrances, paints and cosmetics. Moreover, it is also used by the pharmaceutical and food industries as an aromatic component and to give flavor to sweets, candies and chewing gums. (ASSOCIACAO BRASILEIRA DOS EXPORTADORES DE CITRICOS-SUBPRODUTOS DA LARANJA-BRAZILIAN ASSOCIATION OF CITRIC EXPORTERS- ORANGE BY-PRODUCTS).

D-limonene is a natural monoterpene, and, in plants, it is formed from two isoprene units. It has the following chemical structure: Limonen Due to its lipidic nature, the monoterpene D-limonene easily crosses the biological membranes that are formed by phospholipid bilayers, and, for this reason, it is quickly absorbed into the bloodstream and distributed to the tissues. In the tissues, it is biotransformed through enzymatic reactions capable of increasing the hydrosolubility of the composition so that it can be eliminated from the organism. The enzymatic oxidation catalyzed by the system of monooxygenase cytochrome P-450 dependents is the main metabolic via for D-limonene

biotransformation. Its oxidated metabolites are combined either with glycuronic acid or with glutathione in reduced form, as well as through enzymatic catalysis, and are eliminated through the body liquids, mainly in the bile or in the urine (The Flavor and fragrance high production volume consortia. The terpene consortium).

The main metabolites of the D-limonene are carveol, trans-isopiperitol, perillyl alcohol, and limonene epoxide, which have the following chemical structures: tpt limonen [J 6-Monooxygena. se--Y* Limonene r Limonene L1. 11011B11B r Limonene 3-Motnooxygenase [ Y '-"' . -h MMtfHX : ! MD ? *Qa-'*"'' (+)-Limonene trans-isopiperitenoi eHOM jt LimoneT-Moiiooxyg'enase t J Limone Limone ase (% "or mo Y 4 El +% BUP3+S Limonene Perillyl Alcohol j [J Limonene i. s-Monooxvsenase J ,--_ L''\ - Mi MO-tNt--- (+)-R)-Limonene (49)-Limonexle :

The toxic action mechanism of D-limonene in mice is related to the formation of a nephropathy, while for other mammals, including human beings, D-limonene has a low toxic potential; it is neither genotoxic nor teratogenic.

However, in insects and in larvae, the toxic action WO 2005/034631 PCT/BR2004/000191 mechanism is directly linked to the breathing system of these organisms. In the insects, the external openings or spiracles link to the trachea, which are fine tubes that start from the surface of the body, and branch out until 5 they get to all the organs and internal tissues. They develop as invaginations of the body wall and end in microscopic tracheal cells that extend as intracellular tracheoles, which form the capillary nets in the tissues.

The final part of the tracheole is full of liquid, by which 10 oxygen is spread to the adjacent cells, and, carbon dioxide, from those latter to the tracheoles. Obstructing the spiracles or external openings through which the oxygen enters and the carbon dioxide goes out, with an oil pellicle, breathing is interrupted and the organism dies 15 by asphyxia (STORER, T. I. ; USINGER, R. L. ; STEBBINS, R. C AND NYBAKKEN, J. W.; ZOOLOGIA GERAL-[GENERAL ZOOLOGY] i 6a ed. , Companhia Editora Nacional, 1991).

US Patent 3,954, 991 and US Patent 3,972, 897 describe the use of a product that is a result of the condensation 20 of limonene with sesamol as a larvicide. Limonene is also used along with mineral oils as a larvicide, as described by US Patent 5, 814, 325. In addition, limonene, being liposoluble, can act solubilizing the membrane lipids, with destructuring of the plasmatic membrane of the cells. It 25 can thus lead to destruction of the celll and death of the insect and/or larva.

The mosquitoes larvae include Lutzomia Longipalpis, Culex Quinquefasciatus, Anopheles Darlingi, Anopheles Aquasalis, Anopheles Albitarsis, Anopheles Cruzi, Anopheles 30 Bellator, and especially Aedes aegypt.

SUMMARY OF THE INVENTION The present invention provides a new product for the effective elimination of mosquitoes larvae. The present invention concerns a larvicidal composition consisting of orange oil, ethyl lactate, ethanol, a food grade emulsifier, and water.

BRIEF DESCRIPTION OF THE DRAWINGS The graph in Figure 1 shows the effectiveness of the product on Aedes aegypt larvae. The dose of the product is described in pL per 250 mL.

The graph in Figure 2 shows the effectiveness of the product on Aedes aegypt larvae. The dose of the product is described in ppm, or pg per liter.

DETAILED DESCRIPTION OF THE INVENTION The larvicide of the present invention has as active principles the associated action of the limonene present in the orange oil and the ethyl lactate, an ester derived from products of the lactic and alcoholic fermentation of sugars.

The application in aqueous systems, natural habitat of mosquitoes larvae, renders the use of an emulsifier necessary, since limonene is insoluble in water.

With the intention of producing a formulation in which all ingredients derive from natural products, the use of natural emulsifiers derived from esterification reactions of carbohydrates and fatty acids has been adopted. These compounds are usually used in food products, among which we find oleate, stearate, palmitate or sorbitan laurate, either ethoxilated or not.

The formulation uses a concentration (% v/v) ranging from 0,1 to 99, 9% orange oil, 1 to 50% emulsifier, 0,1 to WO 2005/034631 PCT/BR2004/000191 99% ethyl lactate and 1 to 50% ethanol, using water as balance ; preferably between 5 and 50% orange oil, between 5 and 30% emulsifier, between 7 and 30% ethyl lactate, and between 0,1 and 5% ethanol, using water as balance.

5 The following examples are presented with the purpose of only to illustrate, not to limit the scope of the invention.

EXAMPLES 1. Preparation of the larvicidal composition 10 The composition of the tested product was 44, 4% orange oil, 24% ethyl lactate, 27% emulsifier, 1, 0% ethanol and 3, 6% water, being obtained through the simple mixture of each component.

2. Effectiveness test of the product 15 In the experiments, an amount of the product in pL (variable from 1 to 10 uL) was diluted in 250 mL of distilled water. 1 mL of this solution was added to each experimental pot containing 20 larvae of Aedes aegypt mosquito. The volume of this experimental pot was adjusted 20 to 25 mL ; therefore, 24 mL of water was added to 1 mL of the solution of the product previously described.

An incubation time of 24 hours in a muffle furnace was used, with an average temperature of 27,7 °C and an average humidity of 48, 1%. The best results were obtained in an 25 average temperature of 28, 3 ° C and an average humidity of 41, 8%.

3. Evaluation of the effects of the product The method used to evaluate the effect of the product 30 as a larvicide, in which 20 larvae are put in each pot, i. e. , 8 experimental pots and 4 control pots, follows the WHO rules (World Organization of Health).

In the experiments, an aliquot of the product in pL (variable from 1 to 10 pL) was diluted in 250 mL of distilled water, and 1ml of this solution was added to each experimental pot containing 20 larvae of the Aedes egypt mosquito. The volume of this experimental pot was adjusted to 25 mL ; therefore, 24 mL of water was added to 1 mL of the solution of the product previously described.

An incubation time of 24 hours in a muffle furnace was used, with an average temperature of 27, 7 °C and an average humidity of 48,1%. The best results were obtained in an average temperature of 28, 3 ° C and an average humidity of 41, 8%. Figures 1 and 2 illustrate the results of the product application on Aedes egypt larvae. It can be observed that 100% of the larvae were killed with doses between 9 and 10 pL/250 mL, or 35 to 40 ppm of the product.

The previous description is presented to allow someone else dealing with the technique to reproduce or use the present invention. The several modifications will become quickly evident to those familiar with the technique. Also, the generic principles defined in the present description can be applied to other modalities without the use of the invention licensing. Thus, the present invention is not intended to be limited to the description herein, but it should reach a broader range of applications compatible with the principles and new aspects presented in this report.