GB2623098A

GB2623098A - Aqueous composition containing a copper salt and use thereof as a fungicide or bactericide

Info

Publication number: GB2623098A
Application number: GB2214642.7A
Authority: GB
Inventors: Timothy Bristow James
Original assignee: Rotam Agrochem International Co Ltd
Current assignee: Rotam Agrochem International Co Ltd
Priority date: 2022-10-05
Filing date: 2022-10-05
Publication date: 2024-04-10
Also published as: GB202214642D0

Abstract

Aqueous composition with pH of less than three, the composition comprising copper ions. The copper ions are preferably derived from a copper salt e.g. copper sulphate, basic copper sulphate, copper sulphate pentahydrate, copper acetate, copper amino acid, copper rosinate, copper hydroxide, copper oxychloride, calcium copper oxychloride, copper hydroxide (II) and cupric oxychloride, calcium chloride-copper oxide, cupric sulphate, or Bordeaux mixture. The composition may additionally comprise: an acidifying agent, e.g. sulphuric acid or hydrochloric acid; a nonionic surfactant; defoamer; thickener; bactericide; antifreezing agent; colourant; and adhesive. The concentration of the copper ions may be 0.05 – 12 % by weight. The pH is most preferably 1-2. Most preferably, the composition comprises: 0.1-10 % copper ion; 0.1-10 % auxiliary agents; 0-5 % adjuvant; 3-8 % acidifying agent; and water, with pH 0.5-3. The composition is used to control, prevent, or treat phytopathogenic fungi or bacteria. The method for controlling, preventing, or treating infestations of phytopathogenic fungi or bacteria in plants comprises applying the composition to the leaves, stems, branches, root, or seed of the plant or to the locus where the plant is/will be growing. The plant to be treated may be cucumber, grapes or a citrus tree.

Description

AQUEOUS COMPOSITION CONTAINING A COPPER SALT AND USE THEREOF AS A FUNGICIDE OR BACTERICIDE

The present invention relates to an aqueous composition comprising a copper salt. The present invention also relates to the use of the aqueous composition for the prevention or treatment of phytopathogenic fungi or bacteria.

Copper compounds are known to be effective in a range of pesticidal applications and are considered to be the first compounds used against phytopathogenic fungi. Bordeaux mixture, for example, is a known fungicide and comprises a mixture fo copper (II) sulphate and calcium oxide. Bordeaux mixture can inhibit spore germination or hypha growth of pathogenic bacteria by releasing soluble copper ions. The large release of copper ions can also coagulate the cell protoplasm of pathogenic bacteria and play a bactericidal effect.

When some water-soluble copper salts are used as plant sprays, the salts deposit on the surfaces of plants and kill fungi on these surfaces. This mode of action is a protective mode because it prevents the fungus from penetrating into plant tissues. At the same time, the infected plants are not affected by the treatment. Since copper ions cannot penetrate into plant tissues, there is no effect on fungi found in plant tissues. Therefore, the use of these copper salts is limited to a very narrow range of protective control.

Currently, copper-based products are widely used in agriculture. Various types of copper compounds can be used to effectively treat various plant pathogens. However, undesired toxicological effects can result from their continued use. Therefore, reducing the amount of metallic copper employed is particularly important.

At present, the global health and environmental regulations are becoming increasingly stricter. Farmers all over the world face a problem: on the one hand, the control of destructive pathogens requires more pesticidal products; on the other hand, there is growing pressure from regulators to reduce chemical residues in crops and soils by limiting the use of pesticidal products.

EP 1471787 describes a fungicidal composition, which may be used to reduce the amount of copper employed by mixing copper hydroxide with at least one other inorganic copper salt, such as basic copper chloride, tribasic copper sulfate, Bordeaux mixture and calcium copper oxychloride. However, the reduction in metallic copper content that can be obtained using these techniques is limited and remains unsatisfactory.

US 4,075,326 discloses the use of a combination of an inorganic copper salt and an unsaturated dibasic organic acid copper salt. However, this formulation does not always lead to the real reduction of the copper dosage.

US 6,139,879 describes an aqueous bactericide/fungicide comprising a complex of copper and ethylenediamine-di-o-hydroxyphenylacetic acid (EDDHA).

US 6,471,976 describes an aqueous bactericide/fungicide comprising a complex of copper and a partially neutralized polycarboxylic acid.

US 6,562,757 describes a plant protection composition comprising a copper source in unchelated form and a slightly soluble calcium, zinc or manganese chelate. After application of the composition, the copper chelate is formed in situ and gradually released, thereby prolonging the application interval.

A new therapeutic/systematic fungicidal preparation containing a copper salt as an active ingredient is described in US 6,472,347. The preparation mainly consists of a copper salt in chelated form, a polymeric media and a natural resin. When applied, the polymeric material adheres to the surface of the plant and allows copper ions to penetrate into the plant tissues over a prolonged period of time. The preparation can be used to obtain a fungicidal activity with a long delay.

It is clear that there has been significant attention paid to the development of fungicidal and bactericidal formulations containing copper as the active ingredient. However, there remains a need to provide a copper-based bactericide/fungicide that has the same or higher bioactivity than typical copper-based products, while requiring less copper in the formulation. On the other hand, there is a need for a cost-effective and environmentally friendly method to prepare and use such copper-based formulations.

Unexpectedly, it has now been found that copper components can be formulated to exhibit an enhanced bactericidal/fungicidal efficacy when present in reduced amounts of metallic copper, without using one or more of chelates, polymers or other special adjuvants as required in the copper-based products of the prior art documents described above. In particular, it has surprisingly been found that the activity of a copper component can be enhanced when present in a composition having a low pH.

According to the present invention, there is provided an aqueous composition comprising a copper ion, the pH of the aqueous composition is less than 3.

It has been surprisingly found that the aqueous composition provided by the present invention exhibits a significantly enhanced bactericidal/fungicidal efficacy.

One advantage of the composition is that the amount of copper present in the formulation may be reduced, compared with known compositions, while still achieving a desired pesticidal activity.

The composition comprises copper ions. The copper ions are provided by employing a copper salt that is soluble in water. Any suitable water-soluble copper salt or combination of salts may be used. The copper salt may be one or more of copper sulfate (CuSO4), basic copper sulfate (CuSO4-3Cu(OH)2. H20), copper sulfate pentahydrate (CuSO4.5H20), copper acetate (Cu2(CH3000)4), copper amino acid, copper rosinate, copper hydroxide Cu(OH)2, copper oxychloride (3Cu(OH)2.Cu(C1)2), calcium copper oxychloride (3Cu(OH)2.Ca(C1)2), copper hydroxide (II) and cupric oxychloride (3Cu(OH)2.CuC12), calcium chloride -copper oxide (3Cu(OH)*CaCl2), cupric sulphate (3Cu(OH)2-CuSO4) or Bordeaux mixture (3Cu(OH)2-CaSO4). One preferred embodiment of the composition comprises copper sulphate.

The copper salt may be present in the composition in any suitable amount to provide the required pesticidal activity. The copper salt may be present in an amount sufficient to give a copper ion concentration of from 0.05% by weight of the composition, preferably from 0.1%, more preferably from 0.2%, still more preferably from 0.3%, more preferably still from 0.4%, especially from 0.5% by weight. The copper salt may be present in an amount sufficient to give a copper ion concentration of up to 12% by weight of the composition, preferably up to 11%, more preferably up to 10%, still more preferably up to 9%, more preferably still up to 8.5%, especially up to 8% by weight, more especially up to 7.5% by weight. The copper salt may be present in an amount sufficient to give a copper ion concentration of from 0.05 to 12% by weight, preferably from 0.1 to 10% by weight, more preferably from 0.3 to 9% by weight, still more preferably from 0.4 to 8%, more preferably still from 0.4 to 7.5% by weight, especially from 0.5 to 7.5% by weight.

The composition provided by the present invention has a low pH. In particular, the composition has a pH of less than 3. The pH of the composition is preferably less than 2.8, more preferably less than 2.6, still more preferably less than 2.5, more preferably still less than 2.4, especially less than 2.3, more especially less than 2.2, still more especially less than 2.1, in particular less than 2. The pH of the composition is preferably at least 0.5, more preferably at least 0.6, still more preferably at least 0.7, more preferably still at least 0.8, especially at least 0.9, more especially at least 1. The pH of the composition may be in the range of from 0.5 to 3.0, preferably in the range of from 0.6 to 2.8, more preferably in the range of from 0.8 to 2.5, still more preferably in the range of from 1.0 to 2.0.

The pH value of the aqueous composition may be 0.6 ± 0.01, 0.8 ± 0.01, 1.0 ± 0.01, 1.1 ± 0.01, 1.2 ± 0.01, 1.3 ± 0.01, 1.4 ± 0.01, 1.5 ± 0.01, 1.6 ± 0.01, 1.7 ± 0.01, 1.8 ± 0.01, 1.9 ± 0.01, 2.0 ± 0.01, 2.2 ± 0.01, 2.4 ± 0.01, 2.5 ± 0.01, 2.8 ± 0.01 or 3.0 ± 0.01.

Suitable techniques for determing the pH of the solution are known in the art.

Values of pH indicated herein are at ambient temperature.

To achieve the low pH, the composition may comprise an acidifying agent. Any suitable acid may be used to acidify the composition. The acidifying agent may be selected from at least one of sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, acetic acid, citric acid, oxalic acid, malonic acid, fumaric acid, lactic acid, tartaric acid, potassium bisulfate, sodium bisulfate, potassium dihydrogen phosphate, sodium dihydrogen phosphate, citric acid-phosphate buffer and phosphate-acetate buffer. Preferred acidic compounds include one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, citric acid, acetic acid, malonic acid, fumaric acid, lactic acid, tartaric acid, sodium bisulfate and potassium bisulfate.

The acidifying agent may be present in any suitable amount to provide the required pH of the aqueous composition. The acidifying agent may be present in an amount of from 1% by weight of the composition, preferably from 1.5%, more preferably from 2%, still more preferably from 2.5%, more preferably still from 3% by weight, especially from 3.5% by weight of the composition. The acidifying agent may be present in an amount of up to 12% by weight of the composition, preferably up to 11%, more preferably up to 10%, still more preferably up to 9%, more preferably still up to 8% by weight of the composition, especially up to 7.5% by weight. The acidifying agent may be present in an amount of from 1 to 12% by weight, preferably from 2 to 10%, more preferably from 3 to 8% by weight, especially from 3.5 to 7.5% by weight.

As noted above, one advantage of the composition of the present invention is that the amount of copper component employed can be reduced, while still maintain the required efficacy of the composition in controlling bactericidal/fungicidal infestations.

Accordingly in a further aspect, the present invention provides an aqueous composition comprising a copper salt in an amount sufficient to give a copper ion concentration from 0.1 to 10.0% by weight and an acidifying agent.

The composition of the present invention many further comprise one or more auxiliary agents. The term "auxiliary agent" should be understood as a compound that improves the effectiveness of the active ingredients when applied to treat soil and plants. The term 'effectiveness' means that the auxiliary agent produces one or more of the following effects: increasing the activity of active ingredients; improving absorption and spreading of active ingredients on target surfaces; improving the rain scouring resistance of active ingredients; improving the compatibility of active ingredients with fertilizers and/or micronutrients and/or other components of the spray solution; reducing photodegradation of active ingredients; reducing the amount of drift droplets from the spray solution; and reducing the amount of foam in the spray solution.

In one embodiment of the present invention, the auxiliary agent is a surfactant, preferably a nonionic surfactant. The nonionic surfactant is preferably selected from alkyl glycosides, alkoxylated alcohols, alkoxylated vegetable oils, esters of polyols, alkoxylated amines, alkoxylated esters, alkoxylated alkyl or aryl phenols, and ethylene oxide/propylene oxide copolymers.

The auxiliary agent, such as one or more surfactants, may be employed in any suitable amount. The auxiliary agent may be present in an amount of from 0.1 to 10% by weight, preferably in from 0.2 to 9%, more preferably from 0.5 to 8%, still more preferably from 0.8 to 7%, especially from 1 to 6% based on the total weight of the aqueous composition The aqueous composition may also comprise one or more adjuvants or additives. Such adjuvants and additives for formulating pesticidal components are known in the art and their use will be understood by the skilled person. For example, the composition may further comprise at least one additive/adjuvant compound selected from defoamers, thickeners, bactericides, antifreezing agents, colorants and adhesives.

Non-limiting examples of suitable defoamers include silicone emulsions, such as Silikon SRE, available from Wacker, Germany, or Rhodorsil, availalbe from Rhodia, France; long chain alcohols; fatty acids; fatty acid salts; and organofluorine compounds and mixtures thereof.

Suitable thickeners include polysaccharides, such as xanthan gum, carboxymethyl cellulose, organoclay (organically modified or unmodified), polycarboxylates and silicates.

Suitable antifreezing agents include ethylene glycol, propylene glycol, urea and glycerol.

Suitable bactericides include bronopol and isothiazolinone derivatives, such as alkylisothiazolinones and benzisothiazolinones.

Suitable colorants include slightly water-soluble pigments and water-soluble dyes. Non-limiting examples include Rhodamine B, Solvent Red 1, Pigment Blue 15:4, Pigment Blue 15:3, Pigment Blue 15:2, 35 Pigment Blue 15:1, Pigment Blue 80, Pigment Yellow 1, Pigment Yellow 13, Pigment Red 48:2, Pigment Red 48:1, Pigment Red 57:1, Pigment Red 53:1, Pigment Orange 43, Pigment Orange 34, Pigment Orange 5, Pigment Green 36, Pigment Green 7, Pigment VVhite 6, Pigment Brown 25, Basic Violet 10, Basic Violet 49, Acid Red 51, Acid Red 52, Acid Red 14, Acid Blue 9, Acid Yellow 23, Basic Red 10, Basic Red 108, iron oxide, titanium oxide, and ferric ferrate hexacyanide.

Suitable adhesives include polyvinylpyrrolidone, polyvinyl acetate, polyvinyl alcohol, polyacrylates, biological or synthetic waxes and cellulose ethers.

In a further aspect, the present invention provides the use of an aqueous composition as hereinbefore described for the control, including prevention or treatment, of phytopathogenic fungi or bacteria.

The present invention further provides a method for the control, including prevention or treatment, of infestations of phytopathogenic fungi or bacteria in plants, the method comprising applying the aqueous composition as hereinbefore described to the leaves, stems, branches, roots, and/or seeds of the plants, or to the locus in which the plants are growing or will be grown.

The aqueous composition of the present invention is particularly effective for controlling a large number of plant bacterial diseases in various cultivated plants, for example cereals, such as wheat, rye, barley, triticale, oats or rice; beets, such as sugar beets or fodder beets; fruits, such as pome fruits (apples, pears, etc.), stone fruits (plums, peaches, almonds, cherries, etc.) or small seedless fruits also known as berries (strawberries, raspberries, blackberries, gooseberries, etc.); legumes, such as lentils, peas, alfalfa or soybeans; oil plants, such as oilseed rape, leaf mustard, olives, sunflowers, coconuts, cocoa beans, castor oil plants, oil palm, peanuts or soybeans; cucurbitaceous plants, such as winter squash, cucumbers or melons; fibrous plants, such as cotton, flax, hemp or jute; citrus fruits, such as oranges, lemons, grapefruits or tangerines; vegetables, such as spinach, lettuce, asparagus, cabbage, carrots, onions, tomatoes, potatoes, gourds, or bell peppers; laurel plants, such as avocado, cinnamon, or camphor; energy and feedstock plants, such as maize, soybean, oilseed rape, sugarcane or oil palm; maize; tobacco; nuts; coffee; tea; banana; grapevines (table grapes and wine grapes); hops; lawn; stevia rebaudiana (also known as Stevia); natural rubber plants; or ornamental and forest plants, such as flowers, shrubs, broadleaf or evergreen trees (conifers, eucalyptus, etc.); and plant propagation materials, such as seeds and crop materials of these plants.

The composition is preferably used to control a large number of fungal and bacterial diseases in field crops and cash crops, such as potatoes, sugar beets, tobacco, wheat, rye, barley, oats, rice, maize, cotton, soybeans, oilseed rape, legumes, sunflowers, coffee or sugarcane; fruits (apples, citrus, pears); grapevines; fruit trees (grape vines, citrus trees, pear trees, apple trees); ornamental plants; or vegetables, such as cucumbers, tomatoes, kidney beans or winter squash.

The aqueous composition of the present invention can be used to effectively control a range of phytopathogenic fungi, such as plasmopara viticola on vine plants, phytophthora spp. on vegetables, pseudoperonospora cubensis on cucurbitaceous plants, peronospora tabacina on tobacco, bremia lactucaee on lettuce and spinach, venturia spp. on fruit trees, uromyces appendiculatus on kidney beans, altemaria spp. on vegetables and fruit trees, sphaeroteca fuliginea on cucurbitaceous plants, etysiphe spp. on vegetables and cereals.

In particular, the composition is effective in the control of pathogenic blight (late blight) in tomatoes, cucumber downy mildew, grape downy mildew, tomato rhizoctonia solani kuhn (early blight), potato rhizoctonia solani kuhn (early blight), and strawberry leaf spot.

The composition of the present invention can also effectively control bacterial diseases of plants without causing undesired phytotoxic effects. Examples of plant bacterial diseases that the composition can effectively control include xanthomonas campestris of citrus, pseudomonas syringae pv tomato of tomato plants, pseudomonas syringae pv actinidiae of kiwi plants, pseudomonas lachtymans of gourds, xanthomonas campestris pv campestris of lettuce, pseudomonas viridit7ava of vegetables, xanthomonas juglandis of walnut trees, and xylellafastidiosa of olive trees.

The composition may be applied to plants or parts thereof, particularly all parts of plants, such as leaves, stems, branches and roots, or the soil in which the plants are to be or have been planted and grow.

The composition can effectively carry out preventive, curative and eradication treatments of infestations, while exhibiting little to no phytotoxicity to the target crops.

The aqueous composition of the present invention may be applied to plants by any suitable techniques, in particular spraying, especially foliar spraying. The application can be carried out by means of conventional spray techniques using, for example, water as the carrier. Typical application rates are from about 10 to 2000 I./ha, preferably from 50 to 1000 L/ha. In one embodiment, from 20 to 2000L, preferably from 50 to 400L of ready-to-use spray solutions are applied per hectare.

In one specific embodiment, the aqueous composition of the present invention comprises: one or more copper salts in an amount to provide a copper ion concentration of from 0.1 to 10 wt%; from 0.1 to 10 wt% of one or more auxiliary agents; from 0 to 5 wt% of one or more adjuvants; from 3 to 8 wt% of one or more acidifying agents; and water making up to 100 wt%; wherein the pH of the composition is in the range of from 0.5 to 3.

The compositions of the present invention may be prepared simply by combining the components to form a uniform mixture, for example by mixing. Suitable techniques and equipment for preparing the compositions are known in the art and are commercially available.

As hereinbefore described, it has been found that the efficacy of copper ions in aqueous solution in the control of fungal and/or bacterial infestations of plants is significantly increased when the pH of the aqueous solution is below 3.

Accordingly, in a further aspect, the present invention provides the use of a solution pH of less than 3 to enhance the antifungal and/or antibacterial efficacy of an aqueous solution of cooper ions.

Embodiments of the present invention will now be described, for illustrative purposes only, by way of the following working examples.

EXAMPLES

Example 1

A composition was prepared from the following components in the amounts indicated: Copper sulfate 50 g/L (copper ion concentration) Sulfuric acid 50 g/L Water making up to 1 L The composition was prepared by the following method: The sulfuric acid was added to the water while stirring. Thereafter, copper sulfate was added with stirring to obtain a clear solution.

Example 2

A composition was prepared from the following components in the amounts indicated: Copper sulfate pentahydrate 50 g/L (copper ion concentration) Hydrochloric acid 40 g/L Propylene glycol 50 g/L Defoamer 2 g/L Water making up to 1 L The composition was prepared by the following method: The hydrochloric acid was added to the water while stirring. Thereafter, copper sulfate and the other components were added with stirring to obtain a clear solution.

Example 3

A composition was prepared from the following components in the amounts indicated: Copper sulfate pentahydrate 50 g/L (copper ion concentration) Sulfuric acid 60 g/L Alkyl glycoside 50 g/L Propylene glycol 30 g/L Polyvinyl alcohol 5 g/L Defoamer 2 g/L Water making up to 1 L The composition was prepared by the following method: The sufluric acid was added to the water while stirring. Thereafter, copper sulfate and the other components were added with stirring to obtain a clear solution.

Comparative Example 1 A composition was prepared from the following components in the amounts indicated: Copper sulfate 50 g/L (copper ion concentration) Water making up to 1 L The composition was prepared by the following method: The copper sulfate was added to the water with stirring to obtain a clear solution.

Comparative Example 2 A composition was prepared from the following components in the amounts indicated: Copper sulfate pentahydrate 50 g/L (copper ion concentration) Propylene glycol 50 g/L Defoamer 2 g/L Water making up to 1 L The composition was prepared by the following method: The copper sulfate and the other components were added to the water with stirring to obtain a clear solution.

Comparative Example 3 A composition was prepared from the following components in the amounts indicated: Copper sulfate pentahydrate 50 g/L (copper ion concentration) Sulfuric acid 1 g/L Alkyl glycoside 50 g/L Propylene glycol 30 g/L Polyvinyl alcohol 5 g/L Defoamer 2 g/L Water making up to 1 L The composition was prepared by the following method: The sufluric acid was added to the water while stirring. Thereafter, copper sulfate and the other components were added with stirring to obtain a clear solution.

pH Measurement The pH values of the compositions of Examples 1 to 3 and Comparative Examples 1 to 3 were measured at ambient temperature. The results are shown in Table 1 below.

Table 1

Example Example Example Comparative Comparative Comparative 1 2 3 Example 1 Example 2 Example 3 pH value 1.45 1.15 0.82 5.52 5.87 4.02 Efficacy Tests Field test 1: Control of cucumber bacterial angular spot disease The treatment plots for the test compositions, the control agent (water) and the untreated control were arranged in random plot. Each plot had an area of 8 square meters. Cucumber plants were cultivated in each plot. The cucumber plants were infected with cucumber bacterial angular spot disease.

The compositions were diluted with water and then sprayed evenly on the surface of the leaves of the cucumber plants (the 3rd-4th leaf stage of growth). Each experiment was repeated 3 times.

The plants were inspected 7 days after treatment, with 8 plants investigated in each plot with all the leaves of each plant being inspected. The observations were recorded.

The grading standard for the observations of the cucumber bacterial angular spot disease are as follows: Grade 0: healthy; Grade 1: the lesion area accounts for 5% or less of the total leaf area; Grade 3: the lesion area accounts for 6%-10% of the total leaf area; Grade 5: the lesion area accounts for 11%-20% of the total leaf area; Grade 7: the lesion area accounts for 21%-50% of the total leaf area; Grade 9: the lesion area accounts for 51% or more of the total leaf area.

The efficacy of each treatment was determined as follows: The disease index and control effect were calculated using the following formulae: l(Number of diseased leaves at all grades x value at corresponding grade) x Disease index - 100 total number of investigated leaves x 9

CK PT

Control effect (%) - x 100

CK

where: OK -disease index of untreated control plot; PT -disease index of treated plot.

The results are set out in Table 2 below.

Table 2

Treatment Preparation Disease Index Control effect (%) dosage amount (average value of 3 (average value of 3 ml/mu repetitions) repetitions) (=0.0667 hectares) Example 1 120 16.12 53.49 13.22 61.86 Example 2 120 14.96 56.84 11.01 68.23 Example 3 120 13.85 60.04 10.18 70.63 Comparative 120 26.33 24.03

Example 1

21.16 38.95 Comparative 120 25.45 26.57

Example 2

20.22 41.66 Comparative 120 23.82 31.28

Example 3

18.87 45.56 Control 34.66 (Water) The results indicated in Table 2 indicate that the composition of the present invention exhibited a significantly improved efficacy in the control of cucumber bacterial angular spot disease than the comparative examples. The observations showed the compositions of the present invention had no adverse effects on the cucumber plants and other organisms.

Field test 2: Control of arape downy mildew

The treatment plots for the test compositions, the control agent (water) and the untreated control were arranged in random plot. Each plot had an area of 10.5 square meters. Grape plants were cultivated in each plot. The grape plants were infected with grape downy mildew.

The compositions were diluted with water and then sprayed evenly on the surface of the leaves of the grape plants (the 3rd-4th leaf stage of growth).

Each experiment was repeated 3 times.

The grading standard for the observations of the grape downy mildew are as follows: Grade 0: healthy; Grade 1: the lesion area accounts for 5% or less of the total leaf area; Grade 3: the lesion area accounts for 6%-25% of the total leaf area; Grade 5: the lesion area accounts for 26%-50% of the total leaf area; Grade 7: the lesion area accounts for 51%-75% of the total leaf area; Grade 9: the lesion area accounts for 76% or more of the total leaf area.

Efficacy of the treatments was determined as set in Field Test 1 above. The results are summarized in Table 3 below.

Table 3

Treatment Dilution Disease index Control effect (cYci) ratio (average value of 3 (average value of 3 repetitions) repetitions) Example 1 600 22.12 56.91 500 18.22 64.51 Example 2 600 21.96 57.23 500 17.01 66.87 Example 3 600 19.85 61.34 500 15.78 69.26 Comparative Example 1 600 35.33 31.18 500 29.16 43.20 Comparative Example 2 600 33.45 34.85 500 27.22 46.98 Comparative Example 3 600 32.82 36.07 500 25.87 49.61 Control 51.34 (Water) The results indicated in Table 3 indicate that the composition of the present invention exhibited a significantly improved efficacy in the control of grape downy mildew than the comparative examples. The observations showed the compositions of the present invention had no adverse effects on the grape plants and other organisms.

Field test 3: Control of citrus canker

The treatment plots for the test compositions, the control agent (water) and the untreated control were arranged in random plot. Each plot had 3 citrus trees. Before the onset of citrus canker, the compositions were diluted and then sprayed evenly on the surface of citrus leaves.

Each experiment is repeated 3 times.

The trees were inspected 7 days after treatment, with 2 plants investigated in each plot and each plant sampled by removing all the leaves on two tree tips at 5 points of the east, west, south, north, and middle.

The grading standards of the citrus canker are as follows: Grade 0: healthy; Grade 1: 1-5 lesions on each leaf; Grade 3: 6-10 lesions on each leaf; Grade 5: 11-15 lesions on each leaf; Grade 7: 16-20 lesions on each leaf; Grade 9: 21 or more lesions on each leaf.

The efficacy of the treatments was calculated as set out in Example 1 above. The results are summarized in Table 4 below.

Table 4

Treatment Dilution Disease index Control effect (cY0) ratio (average value of 3 (average value of 3 repetitions) repetitions) Example 1 600 1.69 79.66 500 1.47 82.31 Example 2 600 1.65 80.14 500 1.44 82.67 Example 3 600 1.61 80.63 500 1.34 83.87 Comparative Example 1 600 2.88 65.34 500 2.55 69.31 Comparative Example 2 600 2.81 66.19 500 2.48 70.16 Comparative Example 3 600 2.78 66.55 500 2.45 70.52 Control 8.31 (Water) The results indicated in Table 3 indicate that the composition of the present invention exhibited a significantly improved efficacy in the control of citrus canker than the comparative examples. The observations showed the compositions of the present invention had no adverse effects on the citrus trees and other organisms.

Claims

CLAIMS1. An aqueous composition comprising a copper ion, the pH of the aqueous composition is less than 3.
2. The aqueous composition according to claim 1, wherein the copper ion is provided by a copper salt selected from one or more of copper sulfate (CuSO4), basic copper sulfate (CuSO4-3Cu(OH)2*H20), copper sulfate pentahydrate (CuSO4*5H20), copper acetate (Cu2(CH3C00)4), copper amino acid, copper rosinate, copper hydroxide Cu(OH)2, copper oxychloride (3Cu(OH)2.Cu(C1)2), calcium copper oxychloride (3Cu(OH)2.Ca(C1)2), copper hydroxide (II) and cupric oxychloride (3Cu(OH)2*CuC12), calcium chloride -copper oxide (30u(OH)*CaC12), cupric sulphate (3Cu(OH)2*CuSO4) or Bordeaux mixture (3Cu(OH)2*CaSO4).
3. The aqueous composition according to any preceding claim, where the copper ion is present in a copper ion concentration of from 0.05 to 12% by weight.
4. The aqueous composition according to any preceding claim, wherein the pH of the composition is in the range of from 0.5 to 3.0.
5. The aqueous composition according to claim 4, wherein the pH of the composition is in the range of from 0.6 to 2.8.
6. The aqueous composition according to claim 5, wherein the pH of the composition is in the range of from 0.8 to 2.5.
7. The aqueous composition according to claim 6, wherein the pH of the composition is in the range of from 1 to 2.
8. The aqueous composition according to any preceding claim, further comprising an acidifying agent.
9. The aqueous composition according to claim 8, wherein the acidifying agent comprises one or more of sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, acetic acid, citric acid, oxalic acid, malonic acid, fumaric acid, lactic acid, tartaric acid, potassium bisulfate, sodium bisulfate, potassium dihydrogen phosphate, sodium dihydrogen phosphate, citric acid-phosphate buffer and phosphate-acetate buffer.
10. The aqueous composition according to claim 9, wherein the acidifying agent comprises one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, citric acid, acetic acid, malonic acid, fumaric acid, lactic acid, tartaric acid, sodium bisulfate and potassium bisulfate.
11. The aqueous composition according to any of claims 8 to 10, wherein the acidifying agent is present in an amount of from 2 to 10% by weight.
12. The aqueous composition according to any preceding claim, further comprising an auxiliary agent.
13. The aqueous composition according to claim 12, wherein the auxiliary agent comprises a nonionic surfactant.
14. The aqueous composition according to claim 13, wherein the nonionic surfactant comprises one or more alkyl glycosides, alkoxylated alcohols, alkoxylated vegetable oils, esters of polyols, alkoxylated amines, alkoxylated esters, alkoxylated alkyl or aryl phenols, and ethylene oxide/propylene oxide copolymers.
15. The aqueous composition according to any of claims 12 to 14, wherein the auxiliary agent is present in an amount of from 0.1 to 10% by weight.
16. The aqueous composition according to any preceding claim, further comprising at least one adjuvant compound selected from defoamers, thickeners, bactericides, antifreezing agents, colorants and adhesives.
17. The aqueous composition according to any preceding claim, comprising: one or more copper salts in an amount to provide a copper ion concentration of from 0.1 to 10 wt%; from 0.1 to 10 wt% of one or more auxiliary agents; from 0 to 5 wt% of one or more adjuvants, from 3 to 8 wt% of one or more acidifying agents; and water making up to 100 wt%; wherein the pH of the composition is in the range of from 0.5 to 3.
18. Use of an aqueous composition according to any preceding for the control, including prevention or treatment, of phytopathogenic fungi or bacteria.
19. A method for the control, including prevention or treatment, of infestations of phytopathogenic fungi or bacteria in plants, the method comprising applying an aqueous composition according to any of claims 1 to 17 to the leaves, stems, branches, roots, and/or seeds of the plants, or to the locus in which the plants are growing or will be grown.
20. The method according to claim 19, wherein the plants are selected from potatoes, sugar beets, tobacco, wheat, rye, barley, oats, rice, maize, cotton, soybeans, oilseed rape, legumes, sunflowers, coffee or sugarcane; fruits (apples, citrus, pears); grapevines; fruit trees (grape vines, citrus trees, pear trees, apple trees); ornamental plants; or vegetables, such as cucumbers, tomatoes, kidney beans or winter squash.
21. The method according to either of claims 19 or 20, wherein the phytopathogenic fungi or bacteria are selected from infestations of plasmopara viticola on vine plants, phytophthora spp. on vegetables, pseudoperonospora cubensis on cucurbitaceous plants, peronospora tabacina on tobacco, bremia lactucaee on lettuce and spinach, venturia spp. on fruit trees, uromyces appendiculatus on kidney beans, alternaria spp. on vegetables and fruit trees, sphaeroteca fuliginea on cucurbitaceous plants, erysiphe spp. on vegetables and cereals; and/or infestations of xanthomonas campestris of citrus, pseudomonas syringae pv tomato of tomato plants, pseudomonas syringae pv actinidiae of kiwi plants, pseudomonas lachrymans of gourds, xanthomonas campestris pv campestris of lettuce, pseudomonas viridiflava of vegetables, xanthomonas juglandis of walnut trees, and xylellafasfidiosa of olive trees.
22. Use of a solution pH of less than 3 to enhance the antifungal and/or antibacterial efficacy of an aqueous solution of cooper ions.