MXPA97000925A - Clarified azadirachta oil and methods for your producc - Google Patents

Abstract

The present invention relates to a clarified azadiracta oil having a cloud point below 13 ° C shows reduced phytotoxicity. Treatment of crude azadirase oil with a dilute aqueous basic solution or with an enzyme having lipid degrading activity produces a clarified azadirate oil having low acceptable phytotoxicity. The methods are acceptable because they reduce or eliminate the waste stream of waxy by-product generated by using the existing methods to clarify azadirate oil.

Description

CLARIFIED AZADIRACTA OIL AND METHODS FOR ITS PRODUCTION CAJffip PE THE INVENTION 5 The present invention relates to the field of biocontrol agents isolated from azadiracta trees and more particularly to a low-phytotoxicity, shelf-stable azadiracta oil which has "t * J acaricidal, fungicidal and insecticidal properties.

BACKGROUND DB THE INVENTION The azadiracta tree, a perennial plant tropical has been used for centuries as a source of pesticides to which insects have not developed resistance. It is known that several extracts of / - the seeds of the azadiracta, particularly those containing the hydrophilic tetranortriterpenoid azadirachtina, influence feeding behavior, metamorphosis (regulating effect of insect growth [IGR]), fecundity and aptitude of numerous species of insects belonging to various orders. REF-24112 The azadiracta oil, which contains azadirach ina, can be mechanically pressed from the seeds of azadiracta cold using oil presses or can be extracted by the use of alcohols or other solvents using a Soxhiet apparatus. Small amounts of azadiracta oil can be obtained by grinding azadiracta seed powder manually after adding a little water (Schmutterer &Helip 1988). The term "azadiracta oil" has been used to describe a variety of materials that contain a mixture of hydrophilic and hydrophobic extractables. The variety of extraction methods and the resulting variety in the composition of the azadiracta oil has produced great confusion about the true properties of the "azadiracta oil". Khan and Wassile (1986) tested the effect of their "azadiracta oil" (prepared by aqueous extraction of seeds or nuclei of azadiracta) in 14 common fungi, which include Trichophytonrubrum, T. violaceus, T. concentrichus, T. mentagrophytes, Epidermophyton floccosum, Mierspor? M ci taneum, Scrophulariopsis brevicaulis, Geotrichum candidum and Fusarium sp and found that they do not inhibit the growth of fungi and in fact, the oil of azadiracta itself actually contains several species of growing fungi. Another anonymous article (Anon, 1986) reports that the "10% azadiracta oil diluted from its concentrated emulsifiable formulation" completely inhibits several fungal species such as Aspergillus niger, Fusarium monoliforme, Macrophomina phaseolina and Drechslera rostrata. However, the specific details of this formulation are not provided. Kahn et al. (1986) report that azadiracta oil (from unidentified source) show no inhibitory effect on the growth of a variety of fungi. In fact, it is reported that azadiracta oil is contaminated with molds that include Aspergillus niger and Aspergillus flavus. Similarly, Sharma et al. (1986) report that 3-5% azadiracta seed oils (no preparation method is provided) have no effect on the control of the Heliothis armígera pod borer in chickpeas, in Gujar et al. (1985) reports that azadiracta seed oil (no preparation method is provided) has no effect on desert locust Schistocerca gregaria. Contrary to this, it has been reported that formulations of azadiracta seeds prepared by squeezing oils from the seeds or by extraction with aqueous solvents are effective insecticides and fungicides. It has been reported that 10% azadiracta oil (unidentified preparation) (Anon 1986) inhibits the growth of certain fungi in vi tro. Dryer (1986) describes that the azadiracta oil obtained by cold manual pressing is similar for the control of phytophagous arthropods with respect to aqueous extracts, - the squeezed and pressed oil is much less active. Similarly, there are discrepancies in the literature about the use of azadiracta oil to control insects. Schmutterer and Hallpap (1986) show that the aqueous extracts of azadiracta seeds are significantly superior to the azadiracta oil to repel tick of the leaves (Scrobipalpa ergasina), larva of the leaves (Phyci ta melogenu) and saltoilla (Jacobiella faciaina). Mansour et al. (1986) report that the pentane extract of azadiracta leaves is much more effective in controlling the spider mite Tetranychus cinnabarinus compared to ethanol or methanol extracts, but surprisingly, pentane extract is less effective in controlling the Phytoseiulus persimilis mite compared to ethanol or methanol extracts. Yamasaki et al. show that the tetranortriterpenoid salanin can be isolated from crude plant extracts, obtained from seeds of azadiracta from India which are known to have a high content of salanin, using hexane. The biological activity of the extract of salanin is reported by the rejection to the feeding and the inhibition of the growth when it is applied to chewing insects such as qorqo.ios and caterpillars. The raw azadiracta oil is not shelf stable and may lose its biocontrol activity. A solvent extraction method of U.S. Patent No. 5,409,708, incorporated in the patent as a reference, can be used to remove components that reduce the stability of the crude azadiracta oil. This method of solvent extraction has the effect of reducing the cloud point of the crude azadiraze oil and increasing the shelf stability of the clarified product. However, the method requires a solvent distillation step and an oil fractionation step, in which certain waxes and fatty acids therein solidify and separate by filtration. In addition, the method significantly reduces the volume of azadiracta oil introduced and therefore generates a waste product stream which must be eliminated at a significant cost to producers or consumers. According to the patent, when 15.9 kg (35 pounds) of crude azadiracta oil is subjected to clarification by solvent extraction, 13.6 kg (30 pounds) of clarified oil and 2.3 kg (five pounds) of azadiraze wax are produced. Although both the clarified oil and the wax fraction are active, the clarified oil fraction is more effective for foliar applications, since the wax fraction 5 shows greater phytotoxicity. Therefore, the serous fraction can find more appropriate use in formulations applied to plants at rest or for non-vegetable material. It would be desirable in the art, for economic and other practical reasons, to produce a clarified X * azadiracta oil having high shelf stability and little foliar phytotoxicity, and at the same time to mimic the production of a by-product of azadiracta wax.

The present invention is summarized in that the cloud point of crude azadiraze oil is reduced by treating the crude oil with an aqueous base or with a lipase 20 which eliminates or virtually eliminates the waxy residue stream from the production process. The clarified azadiracta oil produced in the claimed methods is an insecticide, fungicide and / or pesticide of low phytotoxicity and shelf stable.

It is an object of the present invention to provide a method for producing a shelf stable phytotoxic clarified azadirate oil that avoids the limitations of the above methods and still retains insecticidal, fungicidal and / or pesticidal activity. Other objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description.

DETAILED DESCRIPTION DB THE INVENTION Some active ingredients of the seeds and leaves of the Azadirachtin tropical azadirachta indica tree, particularly the tetranortriterpenoids of azadirachtin and salanin are known for their powerful insecticidal activity. The present invention is directed to various insecticidal and fungicidal formulations prepared from non-polar hydrophobic solvent extracted from azadiracta oil which is substantially free of azadirachtin, and still possesses the ability to repel insect pests from plant surfaces, destroy insect pests in various stages of insect life, particularly in the egg and larva stages and controlling fungal pathogens. The term "substantially free of azadirachtin" is used herein to mean an azadirachte oil having less than 1 weight percent azadirachtin, preferably less than 0.2 weight percent azadirachtin, more preferably less than 0.06 percent by weight of azadirachtin. As used herein, the term "insecticide" is considered to encompass insect repellents, larvicides, ovicides and the like. The term "insecticidal effectiveness amount" or "effective antifungal amount" means the dosage of active substance sufficient to exert the desired insecticidal or fungicidal activity. The term "crude azadirase oil" is used herein to designate an azadiracta oil obtained from azadiracta seeds by extraction or by mechanical ejection. The term "clarified azadirate oil" means an azadiracta oil having a cloud point of 12 ° C or '"" minor. The terms "azadiracta wax" or "azadiracta wax fraction" as used herein interchangeably to designate a fraction of semisolid azadirate wax obtained from crude azadiraze oil. The term "cloud point" means the temperature at which a cloud of wax crystals appears in a liquid when it is cooled for the first time. Point The turbidity of a clarified azadirate oil prepared according to the present invention is easily determined by ASTM D 2500-86, "Standard Test Method for Determination of the Cloud Point of Petroleum Oils" ("Standard Test Method for Cloud- Point of 5 Petroleum Oils "). The reduction in the cloud point is generally correlated with a reduced amount of wax or liquid in an oil. The seeds of azadiracta consist of two parts, a cover that does not contain oil or r: -Q insecticide activity and the core which contains oil and azadiracta. The seeds of azadiracta can be very variable in size, shape and composition. Seeds from around the world can be small and round like a pea or large and long like a bean. In addition, the composition of seeds collected throughout the world vary considerably, as shown in Table A. In particular, we have found that oil derived from azadiracta trees with a high concentration of azadirachtin is both insecticidal and fungicidal.

TABLE A Source of% d core% of their content AZAD content seeds n seed oil tangiag ma / ssk * 5 volatile in% Senegal (Pout) 54 7 22 6. 6 India (Punjab) 55 5. 8 30 1. 6 Togo (Atkpame) 57 7. 3 27 4. 5 Haiti (Arcahie) 51 2. 0 19 2. 7 Ghana (Ba k) 57 6. 4 14 3. 9 * gsk = grams of seed core The insecticidal and fungicidal formulations of this invention are prepared from crude azadirase which has been obtained from azadiracta seeds. There are two main methods for extracting the raw azadiracta oil from the azadiracta seeds: expulsion in which the oil is pressed from the seeds, and extraction in which the oil is extracted from the seeds by solubilization in a solvent. Inherently, the materials manufactured by these methods have very different properties. The oil expelled from the seed will also contain water expelled from the seed by the same process. This aqueous material will transport with it 5 liminoids such as azadirachtin, which themselves have insecticidal activity. The methods of the present invention can be practiced in crude azadiracta oil mechanically expelled or in azadiracta oil crude produced by extraction with solvents. Although either method can be used, solvent extraction is preferred because it provides crude azadiraze oil that has less water and greater activity against insects. The azadiracta crude oil extracted by solvents, hydrophobic, and a method to manufacture it, is described in the US patent No. 5,356,628, which is incorporated herein by reference. In brief, ground azadirate seeds are passed through approximately 5 mesh extracted with a non-polar hydrophobic solvent to remove the crude azadiraze oil. It is preferred to use a significant excess of solvents (a3: l, p: p) to obtain good yields. The solvent must be hydrophobic in a suitable way to prevent excess water from contaminating the product. The water in the extract will cause the azadiracta to be extracted from the seeds and result in hydrolysis of the extract. Non-polar hydrophobic solvents suitable for use in the extraction of crude azadiraze oil from the ground azadiracta seeds include those solvents which have a high solubility of azadiracta oil and substantially no solubility of azadirachtin or water. Preferred non-polar solvents include, but are not limited to, aliphatic hydrocarbons and halogenated aliphatic hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, isooctane, chloropentane, chlorohexane and the like, as well as their isomers; petroleum distillates, petroleum ether and the like; aromatic and substituted aromatic substances such as benzene, toluene, chlorobenzene, benzaldehyde, xylenes and the like; and mixtures thereof. Various additional non-polar solvents having the above characteristics are also known to those skilled in the art and are the choice of a particular solvent that per se is not critical to the invention, provided that the azadirachtin is substantially insoluble therein and the azadiracta oil has a high degree of solubility '"in the same. After the extraction, it is removed substantially all of the solvent of the extract by evaporation at low temperature, preferably evaporation under vacuum to provide the crude azadiracta oil product. The raw azadiracta oil can have up to 40% by weight of waxy contaminants before the treatment in the methods of the present invention. The cloud point of the crude azadirase oil is usually about 15 ° C. The cloud point of the crude azadirate oil can be reduced by using an aqueous base to precipitate out certain waxy contaminants or by adding lipase, which enzymatically reduces the waxy contaminants. In a first method to reduce the cloud point of the crude azadirate oil, the oil of > ^ azadiracta crude is treated according to the Levine wax removal method (U.S. Patent No. 4,035,402, incorporated herein by reference). The crude azadiracta oil is cooled to a temperature below 15 ° C (6 ° F). A cloud point Acceptable is 13 ° C, although 12 ° C or 10 ° C is additionally preferred. The most preferred point of turbidity is less than 10 ° C. The cooling of azadiracta oil at 10 ° C is adequate. A basic aqueous solution diluted to 10-30% by weight is added. The The diluted basic solution may contain between 1 and 5% NaOH, or the stoichiometric equivalent of another alkali. The mixture is then stirred gently for 30-60 minutes until the precipitation of waxy solids (soap) is substantially complete. The amount of solid that The precipitate is small - in the order of 100 grams per kilogram of crude azadiracta oil. The precipitation is substantially complete when no additional precipitate is formed. The desired agitation time can be easily calculated by performing a standard or conventional time course experiment. When the precipitation is substantially complete, the precipitated solids are separated. The solids can be removed by any suitable method to separate a serous solid from a liquid phase, but preferably they are separated by centrifugation. The filtration of the precipitated materials obtained by treatment with the base has shown less utility to reduce the cloud point and extend the shelf life of the clarified product. Centrifugation is also preferred because the residual aqueous material is separated from the clarified oil. In a second method, the crude azadiraze oil obtained as described above, is treated with a lipid degrading enzyme, such as of-lipase to reduce enzymatically or to eliminate unwanted waxy components. Α-lipase is commercially available in purified form from many commercial sources. The lipolase, available from Novo Nordisk, has proven to be adequate. In the lipase method, the crude azadiraze oil is brought to a temperature at which the enzyme retains its lipid degrading activity. This temperature is preferably in the range of 20 to 40 ° C and more preferably to 30 ° C. The lipase is added together with water and the crude azadirase oil is stirred during the reaction time of about 30 minutes, or until an adequate percentage of lipid material has been degraded. It is preferred that more than about 50% of the lipid material is degraded, and more preferably than 75% is the degraded material. It is further preferred that substantially all of the lipid material be degraded. The enzyme lipase is deactivated by heating the treated crude azadiracta oil to a suitable elevated temperature (for example 95 CC) for a sufficient time to eliminate the activity (for example 20 minutes). The solid materials are removed from the crude oil (for example by filtration using a Whatman 340 filter paper or other filtration equipment, or by centrifugation). Approximately 98% recovery is obtained. The recovered clarified azadiracta oil has a reduced cloud point and is shown below to have reduced phytotoxicity relative to the crude azadirase oil. Foliar phytotoxicity can be measured on a rating scale from 1.0 to 4.0, where 1.0 represents zero effect on plants, and 4.0 represents a serious effect, as stated in the following. The phytotoxicity of a material means the phytotoxicity caused by the material when applied to a plant. A rating of 2.8 or higher is unacceptably high, while a rating of 2.3 or less is acceptably low. The phytotoxicity of the azadiracta oil prepared by any of the methods is comparable to that of the azadiracta oil clarified by solvent, but a significantly lower amount of by-product is generated when the oil produced by the methods described herein is clarified. In the compositions and formulations of the invention, the clarified azadiracta oil can be used alone or can be mixed with conventional argonomically inert acceptable adjuvants (i.e., compatible with inert plants and / or insecticides) or physiologically compatible (based on the use proposed insecticide), such as surfactants, stabilizers, antifoaming agents and anti-dust agents which can be added. Examples of compositions and formulations according to the invention include aqueous suspensions and dispersions, oily dispersions, pastes, emulsifiable concentrates, flowable substances, inverted emulsions and aerosol compositions.

The compositions and formulations are prepared in a manner known to those skilled in the art, for example by expanding the active compounds with conventional liquid dispersible carrier carriers and / or solid carriers optionally dispersible with the use of carrier vehicle auxiliaries, eg, carriers. conventional surfactants that include emulsifying agents and / or dispersing agents, whereby, for example, in which water is used as a diluent, the i, organic solvents can be added as auxiliary solvents. Adhesives such as carboxymethylcellulose and natural and synthetic polymers in the form of powders, granules or grids such as gum arabic, polyvinyl alcohol, polyvinylcellulose and polyvinyl acetate can be used in the formulations to improve the adhesion of this insecticide. The azadiracta oil of the present invention can be used alone and / or with a solid such and / or a carrier vehicle dispersible in liquid and / or with another known compatible active agent, especially agents for protection of plants such as other insecticides, artropodicides, nematicides, fungicides, bactericides, rodenticides, herbicides, fertilizers, growth regulating agents, synergistic substances, etc., if desired, or in the form of particular dosage preparations for specific applications applied therefrom, such as solutions , emulsions, suspensions, powders, pastes and granules which, therefore, are ready for use. In general, the insecticidal and fungicidal formulations according to this invention can be prepared by diluting the clarified azadirate oil with about 5 to 50%, preferably 5 to 20% and more preferably 7 to 15% by volume of a emulsifying surfactant and optionally may contain 0-1% PABA or other UV scavenger material. Suitable emulsifying surfactants include sorbitan esters, ethoxylated and propoxylated monoglycerides and diglycerides, acetylated diglycerides and monoglycerides, monoglycerides and lactylated diglycerides, monoglycerides or diglycerides of citric acid esters, sugar esters, polysorbates, polyglycerol esters and the like, and mixtures thereof. the same. Preferred emulsifying surfactants are the polyoxyethylene derivatives of fatty acid partial esters of sorbitol anhydrides which are sold under the tradename Tween 20, Tween 40, Tween 60 and Tween 80. Prior to their final application, these insecticidal and fungicidal formulations They are usually diluted with water.

For foliar application, it has been observed that rates of 0.1 to 10%, preferably 0.25 to 3% of clarified azadirate oil diluted in water are effective to control insect pests and fungal diseases without unacceptable damage in plants. The azadiracta oil can also be used at various dilutions to control the various problems of pests and diseases in guests, horticultural and agricultural crops as well as stored fruits and vegetables. The ; < j azadiracta oil formulations have been shown to be effective in controlling insects such as colorado potato weevil, diamond back moth, white fly, coconut, aphids, sphingid larvae, insect loops , fleas, mosquitoes, flies and similar. They are also effective in controlling fungi such as mildew, mold, dollar spots, brown patches, black spots, botrytis and the like. In addition, the oil of ^ azadiracta clarified can be used to control pests of parasites in mammals such as ticks, lice, mites and scabies or scabies. The clarified azadiracta oil also serves to treat symptoms such as eczema and dermatitis. Therefore, the methods find significant practical and economic utility when applied to the production of clarified azadiracta oil for the formulation as an insecticide, pesticide or fungicide.

Sfi3tflßBEBS.? EjtSt 5 Example 1 - 302.5 grams of crude azadirase oil having a cloud point of -15 ° C is cooled to 4 ° C (40 ° F). A cooled aqueous solution and 1.9 grams of sodium bicarbonate and 127.7 grams of water are added to the crude oil. This mixture is gently stirred for 60 minutes at 4 ° C (40 ° F). The mixture is then centrifuged at 10,000 RPM and 4 ° C (40 ° F) for 10 minutes. 250.66 grams of oil treated with a cloud point of 8 ° C are recovered. The treated oil is formulated for use as a pesticide and has no significant adverse effects on plants. Example 2 - 150 grams of crude azadirase oil having a cloud point of ~ 15 ° C is cooled to 10 ° C. A solution of 20 grams of water and 0.75 grams of baking soda are also cooled to 10 ° C and then added to the cooled crude oil. The mixture is stirred gently at 10 ° C for 30 minutes. The clarified oil is separated from water and wax by centrifugation at 10 ° C and 10,000 RPM for 40 minutes. He The clarified oil is then filtered through Whatman 40 filter paper. 132.3 grams of treated oil having a cloud point of 11 ° C is recovered. The oil is formulated in a pesticide and has no significant adverse effects on plants. Example 3 - 100 grams of crude oil having a cloud point of ~ 15 ° C is brought to 30 ° C. 0.4 ml of Lipolase (product of Novo Nordisk) is added together with 0.4 ml of water. The solution is incubated at 30 ° C with shaking for 30 minutes. Subsequently the enzyme is deactivated by heating the solution to 95 ° C and keeping it at this temperature for 20 minutes. The oil is filtered using Whatman 340 filter paper. 98 grams of oil treated with a cloud point of 12 ° C are recovered. The treated oil is formulated into a pesticide and has no significant adverse effect on the plants. Example 4 - 150 grams of crude azadirase oil having a cloud point of -15 ° C is cooled to 10 ° C. A solution of 20 grams of water and 0.25 grams of sodium bicarbonate is also cooled to 10 ° C and then added to the cooled crude oil. The mixture is stirred gently at 10 ° C for 30 minutes. The clarified oil is not separated from the water and the wax by centrifugation. Instead, the oil mixture is only filtered through a Whatman 40 filter paper. This oil is formulated into a pesticide and has no significant adverse effects on the plants. However, it becomes easily cloudy and does not have the desired shelf life characteristics. Example 5 - In a comparison of the phytotoxicity of the various azadiracta oils prepared are Impatiens, azadiracta oil is prepared as in Examples 1 to 4 and formulated into a pesticide. Raw or untreated azadirase oil is also formulated into a pesticide. The positive controls are azadiracta oil that has been subjected to wax removal by using the method of clarification with solvent and water. After the formulation, the oily products are diluted 1: 100 with water and sprayed on Impatiens inflorations, thoroughly moistening the plants. Damage is determined the day after spraying. The results are averaged for three sprays each separated by a week. The results are presented in the following table: Test sample Clarification Oil as prepared using example 1 2.3 A Oil as prepared using example 2 1.5 A Oil as prepared using example 3 2.0 A Oil as prepared using example 4 2.0 A Oil without wax solvent 2.1 A Crude oil 2.9 B Water 1.0 A A = statistically identical results Classification scale 1.0 - no effect on the plant 2.0 - light effect, minor bleached on the edges of the flowers or leaves 3.0 - moderate effect, brown spots or edges of the flowers or leaves 4.0 - effect severe, most flowers or brown leaves.

The three oil oil samples as prepared using clarified provide superior results in the phytotoxicity test with respect to the crude oil. The damage that occurs with crude oil may be unacceptable in the commercial market. These examples are exemplary only, but not limiting, and the invention is considered to embrace all such variations and modifications as is included within the scope of the present invention. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (10)

1. A method for preparing an azadiracta oil having a foliar phytotoxicity Acceptably low, the method is characterized in that it comprises the steps of: treating a crude azadiraze oil preparation with a sufficient amount of an aqueous alkaline solution diluted at a suitable temperature for a sufficient time to precipitate a solid, - separating the precipitated solid from the azadiracta oil preparation treated with alkali; and determine the foliar phytotoxicity of the azadiracta oil treated with alkali; 15 in which the foliar phytotoxicity of the azadiracta oil treated with alkali is statistically lower than the foliar phytotoxicity of the crude azadiracta oil.

2. The method according to claim 1, characterized in that the azadiracta oil treated with alkali has a cloud point of 13 ° C or less.

3. The method according to claim 1, characterized in that the azadiracta oil treated with alkali has a cloud point of 10 ° C or less.

4. The method according to claim 1, characterized in that the classification of foliar phytotoxicity of azadiracta oil treated with alkali is 2.3 or less.

5. A method for preparing an azadiracta oil having an acceptably low foliar phytotoxicity, the method is characterized in that it comprises the steps of: treating a crude azadiracta oil preparation comprising lipid material with a sufficient amount of an enzyme having a degrading activity of lipids, at a temperature at which the enzyme retains its lipid degrading activity for a sufficient time to degrade an adequate percentage of the lipid material; inactivate the enzyme; and determining the foliar phytotoxicity of the enzyme-treated azadiracta oil, in which the phytotoxicity of the azadiracta oil treated with enzyme is statistically less than the foliar phytotoxicity of the crude azadiracta oil.

6. The method according to claim 5, characterized in that the azadiracta oil treated with enzyme has a cloud point of 13 ° C or less.

7. The method according to claim 5, characterized in that the azadiracta oil treated with the enzyme has a cloud point of 10 ° C or less.

8. The method according to claim 5, characterized in that the foliar phytotoxicity of the azadiracta oil treated with enzyme is 2.3 or less.

9. An azadiracta oil having an acceptably low phytotoxicity classification prepared in accordance with a method comprising the steps of: treating a crude azadirase oil preparation with a sufficient amount of a dilute aqueous alkaline solution at a suitable temperature for a time enough to precipitate a solid; separating the precipitated solid from the azadiracta oil preparation treated with alkali; and determining the phytotoxicity of the alkali-treated azadiracta oil, in which the foliar phytotoxicity of the azadiracta oil treated with alkali is statistically lower than the foliar phytotoxicity of the crude azadiracta oil.

10. An azadiracta oil, characterized in that it has an acceptably low phytotoxicity, prepared according to a method comprising the steps of: treating a crude azadiracta oil preparation comprising lipid material, with a sufficient amount of an enzyme having degrading activity of lipids, at a temperature at which the enzyme retains the lipid degrading activity for a sufficient time to degrade an adequate percentage of the lipid material; inactivate the enzyme; and determining the foliar phytotoxicity of the azadiracta oil treated with the enzyme, in which the foliar phytotoxicity of the azadiracta oil treated with the enzyme is statistically lower in comparison with the foliar phytotoxicity of the crude azadiracta oil.