MXPA99003729A - Herbicidal composition and use - Google Patents

Abstract

A herbicidal composition, which can be formulated for selective ortotal kill of vegetation or as a growth regulator, comprises a synergistic combination of acetic acid and citric acid. Such composition consists essentially of acetic acid in an amount of from about 2 to about 10 wt.%, citric acid in an amount of from about 1 to about 6 wt.%, the acetic acid and citric acid being present in a synergistic weight ratio of about 1:0.1 to about 1:0.8, the composition being in fully diluted form ready to apply to post-emergent vegetative growth by spraying onto the vegetative growth.

Description

HERBICIDE COMPOSITION AND USE FIELD OF THE INVENTION The present invention relates to herbicidal compositions comprising smérgic mixtures of acetic acid and citric acid.

BACKGROUND OF THE INVENTION There are many herbicidal compositions that are effective in the extermination of all vegetation or selective vegetation. Many of them are based on sophisticated chemicals, some of which are toxic to other life forms. Acetic acid exhibits some effect as a herbicide, while citric acid, at high concentrations, exhibits some effect as a herbicide. There have been suggestions regarding the use of acetic acid as a herbicide, for example in DE 4 030 687 (Kast), which describes such use alone or in combination with tensides.

BRIEF DESCRIPTION OF THE INVENTION The Applicant has found that at present the synergistic compositions of acetic acid and citric acid can be used as a contact herbicide composition to control post-emergence vegetative growth. The essential components of the herbicidal compositions are edible materials and, therefore, can be applied to the vegetation safely without the risk of harming the animals, including humans. Accordingly, in one aspect, the present invention provides an aqueous, novel herbicidal composition for contact extermination of post-emergence vegetative growth, consisting essentially of acetic acid in an amount of about 2 to about 10% by weight; of citric acid in an amount of about 1 to about 6% by weight; the acetic acid and the citric acid are present in a synergistic weight ratio of about 1: 0.1 to about 1: 0.8, the composition is in completely diluted form ready to be applied to the post-emergence vegetative growth by spraying on it. The composition can be prepared by dilution with water from a concentrate. The composition may further contain up to about 0.5% by weight of a wetting agent.

In a further aspect of the present invention, there is provided a method for controlling post-emergence vegetative growth, which comprises applying to vegetative growth an aqueous herbicidal composition according to the invention, wherein the desired degree of extermination is a complete extermination. of vegetative growth or a selected degree of extermination. The herbicidal composition can be applied to the vegetative growth by spray. Acetic acid and citric acid are present in the composition in the proper proportions to achieve a desired degree of extermination for vegetative growth. In addition, the compositions of the present invention are effective as growth regulators for a variety of plants, inhibiting or stimulating the growth of plants according to the ratios used of acetic acid and citric acid. The combinations of acetic acid and citric acid show evidence of systemic activities in some species. The method forms part of a further aspect of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 to 4 are graphic representations of percentage responses for the treatment of certain species with acetic acid, citric acid and mixtures thereof in the experimentation reported in the following Examples.

GENERAL DESCRIPTION OF THE INVENTION Pos itself, acetic acid does not exhibit selectivity in broadleaf weeds and grasses. However, in combination with citric acid, as provided herein, it is possible to selectively control several annual and perennial weeds, including broadleaf weeds in established lawns and grasslands. In the present invention, there is provided an aqueous herbicidal composition for contact killing of vegetative growth, consisting essentially of: acetic acid in an amount of about 2 to about 10% by weight; and citric acid in an amount of about 1 to about 6% by weight; the acetic acid and the citric acid are present in a synergistic weight ratio of from about 10: 0.1 to about 1: 0.8, the composition is in completely diluted form ready to be applied to the post-emergence vegetative growth, spraying on it. The composition can be prepared by dilution with water from a concentrate. A small amount of wetting agent, up to 0.5% by weight may be present. When uses of the composition of the invention include exposure to high temperatures, it may be desirable to retard the evaporation of the aqueous composition by incorporating therein a proportion of a suitable oil, such that the composition is in the form of an emulsion. The emulsion is then spread over the vegetables that are required. The composition of the invention consists of natural and edible components; Namely, acetic acid and citric acid are therefore not only effective as a herbicide, either for the total or selective extermination of vegetation, but they are also safe to use. In contrast, most Herbicides require chemical synthesis and exhibit toxic side effects on animals. The herbicidal composition provided herein is a contact herbicide, which can be applied by spraying the parts protruding from the soil of the weeds to be exterminated, providing a simple mode of administration. The compositions of the present invention, rapidly and consistently, kill the parts of the weeds that protrude from the soil. The damage to the plants is observed a few hours after the application of the compositions of the invention and the plants die within a few days. The compositions of the invention can be used to kill and control a wide variety of broadleaf weeds and annual and perennial grasses, as well as mosses. The representative vegetative growth includes: Annual Broadleaf Weeds Annual Pastures Black Alfalfa Garranchuelo Alsine Cola de Zorra spp.

Quinquefolio (rough) Sheepskin Oxalis spp. Ambrosia spp.

Cressiferous Cressy Romaza Curly Grass Pulguera Edge Bark Wheat Saracen Wild Long Leaf Weed Perennial Quinquefolio (Silver) Dandelion Llantén spp. Linaria Algarroba Tufted Wild Carrot Clover spp. Ear of Mouse spp. Annual Pastures Gramilla Colorada Grass Pastures Grama Bluegrass (Herb for forage) The present invention is further illustrated by the following Examples: Example 1 This example illustrates the synergistic effect of acetic acid and citric acid in the herbicidal compositions. We used corn for fodder, a favorite variety of the gardener, as a representative species for testing, because the combination of acetic acid and citric acid is not a selective herbicide and the corn for forage is a fast-growing plant, it grows easily under conditions greenhouse and is representative of grasses or weeds. The forage maize was planted live in four 4-inch (10.16 cm) paper pots containing HYPONEX®, a growth medium based on topsoil. One seed was sown per pot. The pots were then incubated in a greenhouse. The plants were watered at least once a day on a base as necessary. Greenhouse temperatures varied from 16.66 ° to 31.66 ° C (62 ° to 89 ° F) throughout the growth and trial period. Germination of the seeds occurred four days after planting. The forage corn was in the two-leaf stage (14 days after sowing) at the time of treatment.

The experiments consisted of the following compositions: (1) Product A (acetic acid) at 10, 8.0, 6.0, 4.0 and 2.0% by weight. (2) Product B (citric acid) at 6.0, 4.8, 3. 6, 2.4 and 1.2% by weight. (3) Mixtures of Product A + Product B at five levels, at a weight ratio of acetic acid to citric acid of 1: 0.6: AB 10.0 + 6.0% 8.0 + 4.8 6.0 + 3.6 4.0 + 2.4 2.0 + 1.2 (4) Mixtures of Product A + Product B at five levels, at various ratios of acetic acid to citric acid: AB Ratio 4.0 + 3.2% 1: 0.8 4.0 + 1.2 1: 0.3 4.0 + 0.8 1: 0.2 4.0 + 0.4 1: 0.1 (5 ) Untreated control Surfactant (Product C) was added to each composition, including the untreated control, in 0.1% of the finished spray. Six replicates were included for each composition. The compositions were prepared in deionized water and applied to the foliage using a C02 pressurized sprayer with handle, fitted with a Teejet 8001 nozzle and releasing the equivalent of 50 gallons per acre (foliar spray at near runoff). An untreated control (water + surfactant) was included. The applications were made using a spray pressure of 25 PSI. The area of land was 91.44 cm x 45.72 cm (36"x 18") and the plants were placed in the area of land and the application was carried out by volume (20 ml / soil). The untreated controls received the equivalent amount of water with surfactant but without any added chemicals. The daily temperatures of the greenhouse varied from approximately 18.33 ° C (65 ° F) during the night to 29.44 ° C (85 ° F) during the day. The greenhouse warming was established in such so that the temperature does not fall below 18.33 ° C (65 ° F). The visual evaluations were made from the percentage of necrosis of the total plant at three days after the treatment. The Barrat-Hors fall estimation system was used to estimate the number of damaged plants. This estimation system is an experienced one, from 0 to 11 on the scale from 0 to 11, with 0 that is not harmful and 11 that is 100% damage. On day seventeen, the fresh weight of the plants was taken by cutting the plants within the replicates of treatment at ground level. The fresh weight of each replicate was recorded. The effect of the proportion of the test composition on the damage to the plant and fresh weight was related to the untreated control. The Barrat-Hor sfall numeric damage ratios were converted to the estimated average percent damage using a conversion table developed by Redman King and Brown, Eli Lilly and Company. All recent plant data was recorded in a Quattro PRO WINDOWS Program spreadsheet (version 6.0), to calculate the average values.

All raw data were analyzed by variation analysis (ANOVA 2-Way) using the Quattro Pro program version 6.0. If a significant F test was found at p 0.05 between the concentrations of the composition and the observations, then the average values of the composition were separated using LSD media separation test. The ED25 and ED50 values (Effective dose that causes a 25 to 50 percent reduction in the measured parameter) were determined by regression and test analysis using the Lotus 1,2,3 software. The results obtained in this experiment were tabulated and presented in Tables I, II and III below. As can be observed from these data, the acetic acid applied only to 10, 8, 6, 4 and 2% showed a proportional sensible effect both for the damage in the plant and for the fresh weight of the plant. The highest proportion, 10%, of acetic acid only caused 39% of damage to the plant and 29% of reduction in the fresh weight of the plant. An ED25 value of 7.5% was calculated for the damage to the plant; an ED50 value may not be determined. For a fresh weight reduction, an ED25 value of 22.7% was extrapolated from the data. The citric acid at the tested proportions, 6, 4.8, 3.6, 2.4 and 1.2% was only weakly active causing only light damage and not caused a reduction in the fresh weight of the plant. The proportions tested were too low to allow an ED25 value or an ED50 value to be determined for one or the other parameter. When used in mixtures, acetic acid and citric acid were more effective than either of the two alone and, therefore, synergistic. The synergistic interaction between acetic acid and citric acid is evident from a comparison of proportional response curves prepared from raw data and ED25 values (Table III). Acetic acid alone showed an ED25 value of 7.5 for damage to the plant, citric acid was ineffective in the highest proportion tested and the combination had an ED25 value of 2. 6. This result is an increase in activity approximately three times as compared to acetic acid alone at the same concentration. Similar results were obtained on the effects of fresh weight. The acetic acid had negligible effect on the weight of the plant and an ED25 value was extrapolated to be 22.7; the ED25 value for the mixture of acetic acid and citric acid was 9. 7, about 2.5 times increase as compared to the activity of acetic acid alone.

The four mixtures of acetic acid and citric acid were tested to determine the effect of modifying their weight ratio on the herbicidal activity. Acetic acid was included in each of the test mixtures at a simple ratio of 4.0%. Citric acid was added to produce the following ratios by weight 1: 0.8, 1: 0.3, 1: 0.2 and 1: 0.1. Under the conditions of this test, acetic acid alone at 4.0% provided only minimal activity, causing some phytotoxic effects, but there were no effects on the fresh weight of the plants during the seven days of the course of the test. It is evident that the combinations of acetic acid and citric acid are synergistic and all relationships were tested. The most effective combination found in these tests was 1 part acetic acid to 0.8 parts citric acid. Therefore, it can be observed, from these experiments, that acetic acid was more effective as a herbicide when mixed with citric acid than when it was applied alone. The percentage control evaluation showed that the synergistic action for corn control occurred when acetic acid and citric acid were mixed. The herbicidal activity of acetic acid and citric acid was 2.5 to 3 times greater in combination than either of the two materials applied alone. The combination of the two materials was synergistic over a wide range of concentrations. The compositions also showed a growth regulation capacity, as seen from Table II.

Example 2: This Example illustrates the synergistic effect on the species of broadleaf weeds and selected herbs of acetic acid and citric acid in the herbicidal compositions. The following weed species were used for the tests described in this Example: Common Name Scientific Name Broadleaf Leaf Weeds Xanthium pensylvanicum Red kale, red root Amaranthus retoflexus Grassy Weeds Zacate Foxtail Setaria virdis Perennial Shrubs Olivastro Elaeagnus angustifolia La a on era , the red chelite and the foxtail grass were planted live in paper pots of 20.32 10.16 cm (8 * 4 inches) they contain HYPONEX®, a growth medium based on topsoil. Ajonjera and quelite red seeds were sown in each row; approximately 15 to 20 seeds per row. The foxtail grass was planted in a separate pot in a single row. The row was planted on a large scale. The sown pots were then incubated in the greenhouse. Three-year-old olivestrous plants (40 plants) were purchased and placed in the greenhouse. The plants were watered at least once a day on a base as necessary. Greenhouse temperatures varied from 18.33 ° to 33.33 ° C (65 ° to 92 ° F) throughout the growth and trial period. The plants were grown under greenhouse conditions for 29 days before being used in the test. Germination of the seeds was adequate and the pots were reduced to approximately 3 to 5 and 3 to 6 plants of mange in each row. The sowing of foxtail grass was solid and produced a copious plant herbage. At the beginning of the test, the ajonjera was in the stage of 4 to 6 leaves, the red quelite was in the stage of 8 to 10 leaves and the zacate tail of fox was in the stage of cabbage of the seed of development. The olivestro plants were approximately 3 years old (40.64 at 50.80 cm [16 to 20"] height) and received in two gallon plastic pots The experiments consisted of the following compositions: (1) Product A (acetic acid) at 12.0, 10.0, 8. 0, 6.0 and 4.0%. (2) Product B (citric acid) at 7.2, 6.0, 4.3, 3.6 and 2.4%. (3) Mixtures of Product A + Product B at five levels, which maintain a ratio of acetic acid: citric acid of 1: 0.6: AB 12.0 + 7.2 10.0 + 6.0% 8.0 + 4.8 6.0 + 3.6 4.0 + 2.4 (4 ) Mix of Product A and Product B to one part of mixture: 3 parts of water (6.25% + 3.1% acetic acid: citric acid). (5) Untreated control Surfactant was added to each treatment, including the untreated control at 0.1% of the finished spray. No surfactant was added to the treatment of Product 4.

Seedlings or replication pots were included for each proportion of treatment. The compositions were prepared in deionized water and applied to the foliage using a C02 pressurized sprayer with handle, fitted with a Teejet 8001 nozzle and releasing the equivalent of 50 gallons per acre (foliar spray at almost run off). An untreated control (water + surfactant) was included. The applications were made using a spray pressure of 25 PSI. The area of land was 91.44 cm 45.72 cm (36"x 18") and the plants were placed in the area of land and the application was carried out by volume (20 ml / soil). The untreated controls received the equivalent amount of water with surfactant but without any added chemicals. Daily greenhouse temperatures varied from approximately 18.33 ° C (65 ° F) overnight to 33.33 ° C (92 ° F) during the day. The greenhouse heating was established in such a way that the temperature did not fall below 18.33 ° C (65 ° F). The visual evaluations were made from the percentage of necrosis of the total plant to the three days after the treatment. The Barrat-Hors fall estimation system was used to estimate the number of damaged plants. The effect of the proportion of the test compound on the damage to the plant related to the untreated control. The Barrat-Horsfall numeric damage ratios were converted to the estimated average percent damage using a conversion table developed by Redman King and Brown, Eli Lilly and Company. All plant damage data were recorded in a Quattro PRO WINDOWS Program spreadsheet (version 6.0), to calculate treatment averages. All raw data were analyzed by variation analysis (ANOVA 2-Way) using the Quattro Pro program version 6.0. If a significant F test was found at p = 0.05 between the concentrations of the composition and the observations, then the treatment averages were separated using LSD media separation test. The ED25 and ED50 values were determined by regression and test analysis using the Lotus 1,2,3 software. The acetic acid applied only to 12, 10, 8, 6 and 4% showed a proportional sensible effect for the plant damage (herbicidal activity) in all weed species (Tables IV, V, VI and VIII). Citric acid at the tested proportions, 6, 4.8, 3.6, 2.4 and 1.2%, was inactive or only weakly active. The citric acid only caused light damage to the red quelite and the peonies and did not cause damage to the foxtail grass or the olivestro. When used in mixtures, acetic acid and citric acid were more effective than any of them alone and, therefore, synergistic. The synergistic interaction between acetic acid and citric acid is evident from the comparison of proportional response curves (Figures 1, 2, 3 and 4) and ED50 values (Table VIII). An ED50 value could not be determined for the perennial species, olivastro, due to the low activity of ECO-N-SELECT against this species. For annual weed species, the increase in the activity of the mixture of acetic acid and citric acid over acetic acid is only in the range of about 20 to 40% (in ED50 values). The results of these experiments indicated that acetic acid was more effective as a herbicide when mixed with citric acid than when applied alone. . The evaluation of control percentage and regression lines showed that the synergistic action for the control of all weed species tested occurred when acetic acid and citric acid were mixed. The herbicidal activity was higher by 20 to 40% (when measured in the ED50 value) in combination, than when either of the two materials were applied alone. The combination of the two materials was synergistic over a wide range of concentrations as tested by the regression response.

SUMMARY OF THE DESCRIPTION In the summary of this description, the present invention relates to a novel herbicidal composition comprising synergistic combinations of acetic acid and citric acid, which are diluted with water to provide the desired herbicidal properties. Modifications are possible within the scope of this invention.

TABLE I SYNERGIC HERBICIDES EFFECTS OF ACETIC ACID AND CITRIC ACID MIXTURES. PERCENTAGE OF PHYTO-TOXICITY OF MAIZE PLANTS THREE DAYS AFTER TREATMENT t Percentage of damage, using the Barrat-Horsfall system, on a scale of 1 to 11 with 0 no damage and 11 with 100% damage.

TABLE II SYNERGIC HERBICIDES EFFECTS OF ACETIC ACID AND CITRIC ACID MIXTURES. FRESH WEIGHT OF MAIZE PLANTS TO SEVEN DAYS AFTER TREATMENT TABLE III DAMAGE TO PLANTS AND WEIGHT IN FRESH, ED25 AND ED50 IN% a. i TREATMENT / PARAMETER ED25 ED50 Acetic Acid Damage to Plant only 7.5 ND Weight in Fresh 22.7 t ND Acid Citrus Only Damage to Plant ND ND Weight in Fresh ND ND Acetic + Cítrico Damage to Plant 2.6 5.3 Weight in Fresh 5.3 10.5 ND = Not Determined t Extrapolated Value TABLE IV SYNERGIC HERBICIDES EFFECTS OF ACETIC ACID AND CITRIC ACID MIXTURES. PERCENTAGE OF FITOTOXICITY OF THE AJONJERA SEVEN DAYS AFTER THE TREATMENT t Percentage of damage, using the Barrat-Horsfall system, on a scale of 1 to 11 with 0 no damage and 11 with 100% damage. # Applied to the recommended use percentage for the 300 ml field of ECO-N-SELECT + 700 ml of water.

TABLE V SYNERGIC HERBICIDES EFFECTS OF ACETIC ACID AND CITRIC ACID MIXTURES. PERCENTAGE OF PHYTOTOXICITY OF RED CHELITE SEVEN DAYS AFTER TREATMENT t Percentage of damage, using the Barrat-Horsfall system, on a scale of 1 to 11 with 0 no damage and 11 with 100% damage. # Applied to the recommended use percentage for the 300 ml field of ECO-N-SELECT + 700 ml of water.

TABLE VI SYNERGIC HERBICIDES EFFECTS OF ACETIC ACID AND CITRIC ACID MIXTURES. PERCENTAGE OF PHYTO-TOXICITY OF ZORATE COLA DE ZORRA DAYS AFTER TREATMENT t Percentage of damage, using the Barrat-Horsfall system, on a scale of 1 to 11 with 0 no damage and 11 with 100% damage. # Applied to the recommended use percentage for the 300 ml field of ECO-N-SELECT + 700 ml of water.

TABLE VII SYNERGIC HERBICIDES EFFECTS OF ACETIC ACID AND CITRIC ACID MIXTURES. PERCENTAGE OF PHYTOTOXICITY OF OLIVASTRO SEVEN DAYS AFTER THE TREATMENT t Percentage of damage, using the Barrat-Horsfall system, on a scale of 1 to 11 with 0 no damage and 11 with 100% damage. # Applied to the recommended use percentage for the 300 ml field of ECO-N-SELECT + 700 ml of water.

TABLE VIII EFFECTS OF DOSE VALUES IN ED25 AND ED50 IN ACTIVE INGREDIENT% FOR AJONJERA, RED QUELITE AND ZACATE COLA DE ZORRA. DAYS OF SEVEN DAYS ND Not Determined > 7.2% (highest percentage tested;

Claims (11)

1. CLAIMS 1. An aqueous herbicidal composition for contact extermination of post-emergence vegetative growth, characterized in that it consists essentially of: acetic acid in an amount of about 2 to about 10% by weight; citric acid in an amount of about 1 to about 6% by weight; acetic acid and citric acid are present in a weight-to-weight ratio of about 10: 0.1 to about 1: 0.8, the composition is in completely diluted form ready to be applied to post-emergence vegetative growth, sprinkling it on vegetative growth.
2. 2. The composition, according to claim 1, characterized in that it is prepared by dilution with water from a concentrate.
3. 3. The composition, according to claim 1, further characterized in that it contains up to about 0.5% by weight of a wetting agent.
4. 4. A method for controlling the vegetative growth post -emergence, which comprises applying to the vegetative growth an aqueous herbicidal composition, according to claim 1, characterized in that the acetic acid and the citric acid are present in the composition in sufficient proportions to achieve a desired degree of extermination for vegetative growth.
5. 5. The method according to claim 4, characterized in that the desired degree of extermination is a complete extermination of the vegetative growth to which the composition is applied.
6. 6. The method, according to claim 4, characterized in that the desired degree of extermination is a selective extermination of certain of the vegetative growths to which the composition is applied.
7. 7. The method, according to claim 4, characterized in that the herbicidal composition is applied to the vegetative growth by spray.
8. 8. The method, according to the indication 4, characterized in that the herbicidal composition also contains up to about 0.5% by weight of a wetting agent.
9. 9. A method for regulating the increase of vegetative growth, which comprises applying to the vegetative growth an aqueous composition, according to claim 1, characterized in that acetic acid and citric acid are present in the composition in sufficient proportions to achieve a degree desired control for increased vegetative growth.
10. 10. The method, according to claim 9, characterized in that the aqueous composition is applied by spray.
11. 11. The method according to claim 9, characterized in that the aqueous composition also contains up to about 0.5% by weight of a wetting agent.