WO1993013657A1

WO1993013657A1 - Pesticidal non toxic composition and method for combatting pests

Info

Publication number: WO1993013657A1
Application number: PCT/ES1992/000006
Authority: WO
Inventors: Merlin Lee; María Emilia FARRE TORRAS
Original assignee: Tecnoholding, S.A.
Priority date: 1992-01-15
Filing date: 1992-01-15
Publication date: 1993-07-22
Also published as: AU1176792A

Abstract

Pesticidal non toxic composition comprised of an aqueous solution of a cellulose ester, soluble in water and which has a kinematic viscosity appropriate to form on the plants a sticky hygroscopic film. A process for combatting pests is implemented by spraying said solution on plants infested by insects, acarids, fungi, bacteria and germs in order to catch and asphyxiate them.

Description

NON-TOXIC PESTICIDE COMPOSITION AND METHOD FOR COMBATING PESTS BACKGROUND OF THE INVENTION This invention relates to a toxic, toxic, composition that is useful for combating pests, such as insecticide, for killing aphids, jumpers, (from the scarred family) thrips, weevils, etc. and as acaricide, germicide, bactericide and fungicide in general. These insects belong to a large order of insects (eg homoptera), which have mouths that suck, chew, etc. These insects have been a plague for farmers for many years. Aphids, sometimes called aphids, reproduce in huge quantities in a short period of time and destroy many crops. They cause the winding or wilting of cultivated plants by sucking the sap of the stems or leaves. Aphids also destroy crops by carrying viruses such as lettuce mosaic virus. Aphids are also notoriously effective vectors for the yellow zucchini mosaic virus that can produce a total crop failure. There are many species of aphids, each of which is colloquially identified by its host plant. For example, the aphid of the apple, the aphid of the cotton, the aphid of the rose, etc. Most aphids winter in their specific plants in the egg stage.

The jumpers feed on the leaves and are also vectors of organisms that cause plant diseases. These insects suck the sap of the leaves and reduce or destroy the chlorophyll, which leaves the leaves yellow or brown.

Mites exist in several species that cause serious damage to fruit trees, field crops and greenhouse plants. Eggs laid in plants hatch in four or five days and what? - 9 - Mites mature to adulthood in about three weeks.

All the mentioned insects and also the mites are born or sa-iei. from the egg in plants the pesticide can therefore be applied ^~ . plants that are infested with insects and mites. Do legal regulations set limits on the amount of waste? chemicals that can be left in fruits and vegetables to ensure they are well below danger levels. Despite the rules, consumer groups protest that pesticides could result in tens of thousands of cancer cases over the next 50 years. According to Environmental Protection agencies, the use of pesticides, fungicides, herbicides, insecticides and plant growth regulators has more than doubled their use during the period 1969-1989 to approximately 820 million pounds annually. This invention relates to non-toxic or phytotoxic pesticides (insecticides, acaricides, fungicides, bactericides and germicides) that provide a solution for the problems associated with insecticides, acaricides, fungicides, toxic agricultural bactericides.

PREVIOUS TECHNIQUE

The toxic pesticides that are currently used to control insects and mites work by attacking the central nervous system and kill by paralysis or attack the ethanol cycle of the insect or mite and interrupt its development causing death.

Unfortunately, all animals have central nervous systems and use the same metabolic cycle, so killing the insect can also kill other animals that have contact with the pesticide. These chemicals are a danger ^" to people who apply them in the field. Their use increases farmers' safety and liability premiums. Toxic chemical pesticides kill beneficial insects and mites as well as those that destroy crops. Commercial pesticides have been developed to maximize exposure to the target insect or mite and minimize exposure to other animals, but the results have been discouraging. The toxic chemical compounds ?. can they be effective? initially, but over time insects and mites develop immunity and resistance, which means that the chemical in the insecticidal and acaricidal composition must be used in increasing amounts or that new compositions have to be developed. There is literature of hundreds of toxic organic compounds available that are used to kill insects and mites. They include organic derivatives of phosphorus, carbamic acid, nitrophenols and other miscellaneous compounds. These chemicals are mixed with anticoagulant agents, corn or other starch, humectants, diluents and other ingredients to facilitate their preparation and use in application to crops by farmers. US 4 307 115 discloses a typical insecticide containing 90-94% of metomyl as active ingredient, in admixture with measured amounts of silica, corn starch or others, clays and surfactants giving the rest of 10-6% by weight. . In Example 2 of this patent, the composition contains 0.1% methylcellulose. These compositions are dispersible in water and are applied to the cultures in the form of aqueous dispersions. The minor additives in these compositions are simply added for the purpose of facilitating the mixing of the active ingredient with the water. These additives are not effective, in the insecticidal compositions described, for killing insects. Death occurs only by contact with the active ingredient, metomyl.

The active substances are also used as powders in vehicles or solid carriers such as kaolin, plaster, limestone, sodium and potassium alumina silicates, corn or other flours, sawdust, cellulose powder, activated carbon and the like. Dust is spread on plants infested with harmful insects.

THE INVENTION The object of the present invention is to ^'provide a non - poisonous pesticide that is totally effective insect killing mites, fungi and bacteria, leaves no poison of any kind in crops, is economical, easy to dissolve and apply without special equipment . In addition, the pesticide is not phytotoxic or harmful to the environment. These objects are achieved using a composition that kills insects, mites, fungi and bacteria by physical rather than chemical means. The composition is adhesive or sticky. Catch insects and mites and keep them trapped until they die. In addition, the compositions are film-forming and when sprayed on insects and mites, the deposited film blocks the spiracles of the insect's tracheal system and mite and kills by suffocation. The aphids are fixed slightly to the infected plant and some are eliminated by the spray stream. But the adhesive film that covers them cuts off the oxygen supply normally received through the tracheal system. The films of the invention are not only not toxic or phytotoxic, but also biodegradable.

The compositions of the invention consist of a sticky film-forming solution of a water-soluble cellulose ether, which can be sprayed on plants using conventional agricultural spraying equipment. Such water-soluble cellulose-derived ethers may be any of the group comprising sodium carboxymethylcellulose, sodium carboxymethyl-2-hydroxyethylcellulose, 2-hydroxymethylcellulose, methylcellulose, 2- hydroxypropylmethylcellulose, 2-hydroxyethylmethylcellulose, 2- hydroxybutylmethylcellulose, 2-hydroxyethyl ethylcellulose and 2- hydroxypropyl cellulose. The solution is sprayed into small droplets, which are 50-400 microns in size, that settle on the leaves of the plant and form a film that traps insects and mites and covers their eggs.

It also suffocates, due to lack of oxygen, fungi and prevents the installation of spores and the life and penetration of mycelia. Likewise, it also stifles or suffocates the development of bacteria that require oxygen or moisture for their development and reproduction, and prevents their entry into plants through wounds or natural openings, thanks to the protective film. Viruses penetrate the same path.

Since the ether derived from cellulose is soluble in cold water, farmers can prepare the solutions on the farm in drums of 50 to 100 gallons without the expense and hassle of heating the water. Water preferably contains a surfactant to reduce surface tension and facilitate the wetting of insects, mites, fungi and plant leaves. The water-soluble ether derived from cellulose is added as a powder and easily dissolved with stirring. The viscosity of the polymer solution ranges between about 10 and about 3,000 centistocs, preferably 100 and 500 centistocs. Below 10 centimeters the drops do not adhere to insects and other organisms and plants, and drain. No films are formed about insects and other organisms.

Above approximately 3000 centimeters the surface tension is so great that the film formed is discontinuous so that many of the insects, mites, fungi, etc. they have not just been immersed in the movie. Accordingly, the viscosity of the solution is importantc- for the preparation of solutions of the invention.

For example, sodium carboxymethyl cellulose (CMC) is an anionic cellulose ether available as a powder or granules having a granulometry of 50 to 200 microns. The CMC is commercially available in a DS range of 0.38 to 1.4, with DS being the degree of substitution of the -CHzCOOKa groups in the -OH groups of the beta-anhydroglucose rings comprising the ether polymer of cellulose. There are three hydroxyl groups in each ring so that the maximum value of DS is three. As the DS of the CMC increases, the viscosity of the solutions prepared from the CMC increases. CMC is produced commercially in different viscosities. The viscosity is expressed as the intrinsic viscosity in a 2% solution measured at room temperature. Commercial CMC polymers used to illustrate this invention are designated by their viscosity ranges, for example 10-20, 400-800 and 3000-6000 centipoise. Mixtures of CMC having different intrinsic viscosities may be used for the purposes of the invention as long as the resulting solution has a viscosity within the specified limits. As indicated, this range is between 10 and 3000 centimeters, of kinematic viscosity (1 centipoise equal to 1 centistoque multiplied by the density of the liquid).

CMC is commercially available and is produced by several manufacturers. Commercial products used in connection with this invention have been obtained from Sigma Chemical Co. of San Louis, USA, as product nQ C8758 (CMC low viscosity, 10-20 centipoise) and product nQ C4888 (CMC medium viscosity, 4- 800 centipoises). The higher viscosity CMC (3000-6000 centipoise) can be obtained from the Aldrich Chemical Co., Mil Aukee, Wisconsin, USA, with product number 32000306-3). CMC It is recognized by legal regulations as safe for use in food (21 CFR 182.1745).

To be effective in killing insects, mites, fungi, etc. The solution should produce a sticky film that can be sprayed through the nozzle of conventional agricultural spray equipment. As the viscosity of the solution approaches the kinematic viscosity range of 3000, the spray pressure must be increased to produce droplets of the desired size. Agricultural spraying machines are provided with hollow conical nozzles that operate in accordance with the invention using pressures between about 100 pounds / square inch and 600 pounds / square inch. The size of the droplets will vary from 50 microns to 400 microns, depending on the solids content and the viscosity of the solution being sprayed. To improve the wetting of insects, mites and fungi and plant leaves, a surfactant must be added to the water. The water, in which all the solutions of the invention are prepared, contains about 0-1% of a surfactant wetting agent, for example alkyl / aryl polyether alcohols, esters (or ethers) of fatty acid polyethylene oxide, alkyl / aryl sulfonates, alkyl sulfonates and the like. These surfactants are known in the art for use in preparing dispersion of insecticides, acaricides, fungicides, etc. In the solutions of the invention, the surfactants help to make the solution droplets spread on the waxy sheets and penetrate the waxy protective coating of insects, mites, and their eggs, as well as coat spores and fungal mycelia.

The films of the invention are hygroscopic and collect moisture from the air. In some cases, it is desirable to keep the film in a wet and sticky state for up to 24 hours to catch insects that are not in the plant at the time of spraying. This is done by adding a non-toxic salt such as lithium chloride, lithium acetate or potassium acetate in an amount of 0-1.5% by weight. SPECIFIC EXAMPLES

EXAMPLE 1

A solution is prepared by dissolving 5 grams of CMC of low density (10-20 centipoise) and 5 grams of CMC of medium viscosity (400-800 centipoise) in 480 grams of water. Water contains 0.8% surfactant (Amway APSA-80). The solution is mixed with a stirrer to produce a kinematic viscosity of 136.4 centistocs. The solution is placed in a conventional agricultural sprayer and sprayed through the hollow conical nozzle at a pressure of 250 pounds / square inch. The size of the droplets is 100-150 microns. The solution is sprayed on thistles that have myriad aphids on the stems and leaves. The solution is deposited in the stems and leaves of thistle. Immediately after spraying, pieces of the stems with attached leaves were removed and observed through a dissecting microscope. 95% of the aphids in the plant had died without any signs of struggle. It seems they died of suffocation because the sticky film covered or clogged their spiracles. The other 5% fought and lost limbs ending in grotesque positions in death. The examination as confirmed by photographs taken before and after spraying the photographs clearly show with a 30-fold increase in the conditions of insects in both stages. Since aphids hang very lightly on a plant, they have a limited ability to grasp. Therefore, the force of the spray released approximately one third of the aphids of the plant. To determine the status of these aphids, a white background was placed behind the plant on which the aphids released were deposited. Inspection of these insects indicated that they had also died of suffocation. EXAMPLE 2

A solution is prepared by dissolving with stirring 5 grams of CMC of high viscosity (3000-6000 centipoise) and 5 grams of lithium chloride in 489 grams of water containing a surfactant according to Example 1. This solution has a kinematic viscosity of 3038 centistocs . Lithium chloride serves to keep the solution "wet" for a longer period of time by slowing the evaporation rate. The presence of lithium chloride reduces the viscosity dramatically and for this reason the starting material of higher viscosity is used. The solution is placed in a conventional agricultural sprayer and sprayed through a hollow conical nozzle. The spray pressure is 600 pounds / square inch and the droplet size is 300-400 microns.

The solution is sprayed on low-ground bean infected with potato jumpers (empoascafabae). The examination of the plant with increases after about four hours indicated that all jumpers had died.

Jumpers are disturbed by staff and equipment. Extending the period during which the film remains "wet" and sticky, the jumpers that leave the plant are trapped when they return. EXAMPLE 3

A solution is prepared by dissolving 10 grams of CMC of low viscosity (10-20 centipoise) in 480 grams of water containing a surfactant according to Example 1. The solution has a viscosity 10.19 centistoque kinematics. The solution is sprayed from a conventional sprayer as in Example 1 using a pressure of 100 pound / square inch. The size of the droplets is 50 to 100 microns. The solution is sprayed on rose bushes infested with accharides

(prosti kills). The examination with an increase two hours after spraying indicates that all the accharides in the plant had died.

From the foregoing, it is clear that this invention provides a non-toxic biodegradable pesticide that does not harm the most delicate plants or their leaves. It is inexpensive and kills insects, mites, fungi, etc. by physical means instead of chemicals. It was very unexpected that this edible material would kill insects, mites, fungi, etc. by physical means.

It has been proven that the addition to the solution of the cellulose ether, soluble in water, of an amount of starch or modified starch, also soluble in water, allows to obtain a non-toxic pesticide, which is effective in combating plant diseases, such as ildiu, black mold and other diseases and at the same time cover the leaves of plants with a film that prevents a new infection.

A composition consisting of 10-85% by weight of a starch or modified starch, soluble in water, preferably 75%, with 90-15% of a cellulose ether, soluble in water, preferably 25%, is dissolved in water in a concentration of about 0.01-8.0%, with which it is sprayed on the plantation as a solution or a dispersion using a high pressure sprayer.

This composition, when it has been sprayed on a plantation affected by some disease, such as parasitic fungi called powdery mildew (Erysiphales) and hairy mildew (peronosporaleε), a coalescence action between starch and the sticky substance that is a part of these fungi and molds originates. By coalescence, starch stifles the disease and kills it. After a few hours the starch falls and the cellulose ether forms a film that will prevent the plant from being reinfected for more than 14 days.

Claims

1.- Non-toxic pesticidal composition, such as insecticide, acaricide, fungicide, bactericide and antivirocide, comprising an aqueous solution of a cellulose ether, soluble in water, having a kinematic viscosity of about 10 to about 3000 centistocs and producing a hygroscopic sticky film.

2. Composition according to claim 1 having a viscosity between 100 and 500 centistocs.

3. Composition according to claim 1 in which the water soluble cellulose ether has a degree of substitution equal to a value between 0.38 and 1.4.

4. Composition according to claim 1, characterized in that the water-soluble cellulose-derived ether is one of the group comprising sodium carboxymethylcellulose, sodium carboxymethyl-2-hydroxyethylcellulose, 2-hydroxymethylcellulose, methylcellulose, 2 -hydroxypropylmethylcellulose, 2-hydroxyethylmethylcellulose, 2- hydroxybutylmethylcellulose, 2-hydroxyethylene methylcellulose and 2- hydroxypropylcellulose.

5. Composition according to claims 1 and 4, characterized in that in the case of the sodium carboxymethyl cellulose (CMC) with which said solution is prepared, it consists essentially of a mixture of CMC of low intrinsic viscosity (10-20 centipoise) and CMC of medium intrinsic viscosity (400-800 centipoise).

6. Composition according to claim 5, characterized in that said solution is prepared by dissolving approximately 1% sodium carboxymethyl cellulose in water having an intrinsic viscosity of

3000-6000 centipoise and 0-1% of a surfactant, said percentages being by weight.

7.- Method of killing insects such as aphids, jumpers, thrips, etc. and mites comprising spraying the film-forming solution of claim 1 onto a plant carrying said insects and mites to trap said insects and mites and block the tracheal system spiracles.

8. Method according to claim 7, characterized in that the solution is sprayed in the form of droplets of a size of 50 to 100 microns.

9. Composition according to claim 1, which has 0-1% by weight of a surfactant.

10.- Method of killing insects such as aphids, jumpers, tripε, etc. and mites comprising spraying an aqueous film forming solution of an ether derived from water soluble cellulose, containing 0-1% by weight of a surfactant and having a kinematic viscosity of 10-3000 centistocs, on a plant carrying said insects and mites to catch said insects and mites and to block the tracheal system spiracles.

11. Method according to claim 10, characterized in that said solution has a kinematic viscosity of approximately 135 centistocs and is sprayed in the form of droplets having a particle size of 100-150 microns.

12. Method according to claim 10, characterized in that said solution is prepared based on a water-soluble ether derived from cellulose having an intrinsic viscosity of 3000-6000 centipoise and includes 0-1.5% of a non-salt toxic to reduce the rate or rate of evaporation of the solution.

13.- Method of killing insects such as aphids, jumpers, thrips, etc. and mite, fungi, bacteria and germs, characterized in that prepares a composition consisting of 90-15% by weight of a water soluble cellulose ether, and 10-85% of a water soluble starch, which is dissolved in water in a concentration of 0.01-8, 0%, with which the plants to be treated are pulverized to kill said insects, mites, fungi, bacteria and germs.