GB2535569A

GB2535569A - Electrolysed water composition

Info

Publication number: GB2535569A
Application number: GB1518474.0A
Authority: GB
Inventors: Philip Gardner Stephen
Original assignee: Ozone Purification Ltd
Current assignee: OZONE PURIFICATION LTD
Priority date: 2014-12-09
Filing date: 2015-10-19
Publication date: 2016-08-24
Anticipated expiration: 2035-10-19
Also published as: GB2535569B; GB2535568B; GB201518474D0; GB2535568A; GB201518472D0

Abstract

A method for producing electrolyzed water for use in the treatment of pathogens is described. The method comprises preparing an aqueous electrolyte solution at least one anhydrous alkali metal carbonate salt; and at least one alkali metal chloride salt. The electrolytic cell has a plurality of boron-doped diamond (BDD, BDE) electrodes. The method also comprises operating a power supply to apply a predetermined voltage to the electrolyte solution to produce an electrolyzed water biocidal composition comprising a plurality of active molecular and ionic species having biocidal activity. The mixture of at least two salts of the electrolyte are selected such that the dissolved 03 concentration is in the range of from 0.1-1,000 ppm.

Description

Electrolyzed Water Composition

Field of the Invention

The present invention relates to an electrolyzed water composition, and the use of the electrolyzed water composition for the treatment of pathogens, including fungal, 5 bacterial and viral pathogens, within for example the agricultural industry.

Background

There are a number of plant pathogens such as downy mildew, powdery mildew, late onset blight (Phytopthora), Bortrytis and stem Bortrytis which present serious issues to farmers and growers. The plant pathogens may significantly reduce the yield and quality within a wide range of food or flower crops. In some cases, the plant pathogens may destroy up to 100% of viable crops resulting in significant financial losses. These pathogens are often highly selective and affect a very specific food or flower crop. The pathogens are also often very difficult to control in any systemic fashion. The pathogens can continue to spread throughout a crop even with regular spraying with conventional chemical pesticides.

A number of agricultural chemical controls which are currently used to protect crops against plant pathogens are highly toxic to humans. As a result, the grower or farmer must use additional protective equipment and/or wear expensive protective clothing and breathing apparatus. Furthermore, the chemicals may not be used beyond a certain time point in the growing season prior to harvest in order to minimise the risk of chemical residues being present on or in the crops at harvest. The use of these chemicals also has associated environmental implications. The current agricultural controls have come under severe regulatory restriction. Effective disease management options must also be economical. The cost of managing the disease 25 must be less than the value of the crops to be harvested.

There is therefore a need for a biocidal composition with improved efficiency in protecting crops against plant pathogens, lower associated energy and cost implications, and/or reduced environmental and health implications. There is also a need for a method of treating agricultural crops which does not require any additional treatment apparatus.

Summary of the Invention

According to a first aspect, the present invention, there is provided a method for producing an electrolyzed water composition for use in the treatment of plant pathogens, the method comprising: preparing an electrolyte solution comprising water, at least one anhydrous alkali metal carbonate salt, and at least one alkali metal chloride salt; introducing the aqueous electrolyte solution into an electrolytic cell comprising a plurality of boron-doped diamond electrodes; and operating a power supply to apply a predetermined voltage to the electrolyte solution within the electrolytic cell to produce an electrolyzed water composition comprising a plurality of active molecular and ionic species having anti-microbial properties, in which the salts of the electrolyte are selected such that the dissolved Os concentration is in the range of from 1 to 1000 ppm.

Preferably, the salts of the electrolyte are selected such that the electrolyzed water biocidal composition comprises a free accessible chlorine (FAC) concentration in the range of from 0 to 1000 ppm. The electrolyte solution may be introduced into the electrolytic cell in a continuous or batch process manner.

Preferably the at least one chloride salt is potassium chloride or sodium chloride.

Preferably the at least one carbonate salt is anhydrous potassium carbonate or anhydrous sodium carbonate.

The total salt concentration of carbonate salts and chloride salts within the aqueous electrolyte solution is preferably within the range of between about 0.1 g/I and 400 g/I. Preferably, the total salt concentration of carbonate salts and chloride salts within the aqueous solution is in the range of between 0.1 g/I and about 100 g/I, more preferably between 0.5 g/I and 80 g/I, especially preferably between 1.0 g/I and 50 g/I, for example in the range of 1.0 g/I and 5.5 g/I.

The ratio of chloride salts to carbonate salt(s) by weight within the aqueous electrolyte solution is preferably less than or equal to 1:1, more preferably less than 30 or equal to 0.9:1. The ratio of carbonate salts to chloride salt(s) within the aqueous electrolyte solution by weight is preferably greater than 1.1: 1, more preferably greater than 1.15:1 The electrolyte solution can optionally include one or more additional salts to enhance the biocidal properties, in particular the pathogenic activity, of the resultant 5 electrolyzed water composition.

The predetermined voltage is preferably in the range of between about 1 and 1000 volts DC, preferably in the range of between 48 to 96 volts DC.

The power supply preferably has a current in the range of between about 1 and 1000 ampere, preferably at about 24 ampere.

According to a second aspect, the present invention provides an electrolyzed water composition obtainable by a method as described herein.

The plurality of active molecular and ionic species within the electrolyzed water composition may comprise dissolved 03 in a concentration between about 1 and 1000 ppm. The electrolyzed water composition preferably comprises dissolved 03 in a concentration between 10 and 500 ppm, more preferably in a concentration between 50 and 300 ppm.

The composition can be varied in terms of its composition and degree of overpotential by carrying the concentrations of the salts and by carrying the current applied to the solution. In this way, specific electrolyzed water compositions can be created for treating certain microbes or pathogens, including live organisms such as spores and biofilms. The concentrations and overpotential can be varied so as to achieve the required mix between antimicrobial properties, cleaning properties and delivery mechanisms.

According to a further aspect, the present invention provides the use of an 25 electrolyzed water composition as herein described as an antipathogenic composition.

The compositions of the present invention may be used to treat plant pathogens, including for example fungal pathogens and/or bacterial pathogens and/or viral pathogens.

According to a further aspect, the present invention provides a method for treating pathogens, in particular plant pathogens, comprising applying an electrolyzed water composition as herein described to an area, for example a plant crop or an area containing a plant crop, affected with pathogens.

According to a further aspect, the present invention provides an applicator for treating pathogens, in particular plant pathogens, in which the applicator comprises a reservoir comprising an electrolyzed water composition as herein described, and an outlet in fluid communication with the reservoir. The outlet may for example be a nozzle. The applicator may comprise a reservoir which is arranged in use to be connected to a spraying device, a fogging mist device or to equipment, such as for example processing lines or wash systems within the environment to be treated.

The applicator may for example be selected from one or more of: a nebuliser, a fogging mist applicator, a jet spray applicator, a spray applicator, or an irrigation system, or any combination thereof.

According to a further aspect, the present invention provides an apparatus for producing electrolyzed water composition for use in treating pathogens, in particular plant pathogens, the apparatus comprising: a reservoir comprising an electrolyte solution comprising water, at least one anhydrous alkali metal carbonate salt, and at least one alkali metal chloride salt; an electrolytic cell in fluid communication with the reservoir to receive a feed stream comprising the aqueous electrolyte solution; and a plurality of boron-doped diamond located within the electrolytic cell and arranged in use to be connected to a power supply.

The electrolytic cell preferably comprises at least one outlet through which the electrolysed water composition exits the electrolytic cell.

The system may further comprise one or more flow regulators arranged in use to adjust the flow of the electrolyte feed stream between the reservoir and the cell.

The system may further comprise a heater arranged in use to adjust the temperature 30 of the flow of the electrolyte feed stream and/or the electrolyte solution within the cell.

The system may further comprise a control system arranged in use to control the flow rate of the electrolyte feed stream as required, such as for example by controlling the flow regulator(s).

The system may comprise a control system arranged in use to control the power 5 supply to the electrodes.

The system may comprise a control system arranged in use to control the temperature of the electrolyte solution.

Control of the temperature of the electrolyte solution, the flow rate of the electrolyte solution feed stream, and the power supply to the electrodes may be provided by a 10 single control system. Alternatively, these factors may be controlled by separate control systems.

According to a further aspect, there is provided an electrolyte solution comprising at least one anhydrous alkali metal carbonate salt, and at least one alkali metal chloride salt. The electrolyte solution preferably comprises: at least one carbonate salt selected from anhydrous potassium carbonate and/or anhydrous sodium carbonate; and at least one chloride salt selected from potassium chloride and/or sodium chloride. Preferably, the electrolyte solution comprises anhydrous sodium carbonate and sodium chloride.

Brief Description of Figures

Embodiments of the present invention will now be described, by way of example, with reference to the following figures: Figures 1A and 1B are photographic images illustrating the effect of late blight (Phytophthora infestans) on tomato plants when left untreated for ten days (Figure 1A) and when treated with a conventional treatment agent known as Revus for ten 25 days (Figure 1B); Figures 1C and 10 are photographic images illustrating the effect of late blight (Phytophthora infestans) on tomato plants when left untreated for ten days (Figure 1C) and when treated with the Composition of Example 1 for ten days (Figure 1 D); Figure 2 is a graphical representation comparing the effect of applying the composition of Example 1, and two comparative electrolyzed water compositions; and known pesticide Revus to tomato plants infected with late blight; Figure 3 is a graphical representation comparing the effect of applying the 5 composition of Example 1, two comparative electrolyzed water compositions; and known pesticide Signum on the average lesion length on tomato plants as a factor of number of days post treatment; Figure 4 is a graphical representation comparing the effect of applying the composition of Example 1, two other electrolyzed water compositions as comparative 10 Examples; and known pesticide Tebecur on the average lesion length on carrot plants as a factor of number of days post treatment; Figures 5A and 5B are photographic images of tomato plants infected with an inoculum of powdery mildew; Figure 6 is a graphical representation comparing the degree of infection (%) of 15 powdery mildew infected tomato plants 3 weeks after treatment with the composition of Example 1, three comparative electrolyzed water compositions, Amistar (a known fungicide), and without treatment; and Figure 7 is a graphical representation comparing the degree of infection (%) of powdery mildew infected tomato plants 6 weeks after treatment with the composition 20 of Example 1, three comparative electrolyzed water compositions, Amistar (a known fungicide), and without treatment;

Detailed Description

Example 1 -Electrolyzed water composition An aqueous electrolyte solution comprising 14 g sodium chloride and 16g anhydrous 25 sodium carbonate in 12 I of water was prepared. The electrolyte solution was stored within a reservoir chamber in fluid communication with an electrolytic cell.

A feed stream comprising the electrolyte solution was introduced into an electrolytic flow cell. The feed stream can optionally include one or more additional salts to enhance the biocidal properties of the resultant electrolyzed water composition.

The electrolytic cell is a non-membrane electrolytic cell. It is however to be understood that any suitable electrolytic cell may be used.

The electrolytic cell comprises a casing, a plurality of boron doped diamond electrodes (BDEs) located within the cell, and metal 'contact plates' used for 5 transmitting charge across the electrolyte solution.

The BDEs are sheet-like components and are provided in a stack of between 3 and 10 sheets. Each sheet is located at a fixed distance away from an adjacent sheet. The distance between adjacent sheets of BDEs provides a cell gap, which is preferably less than 5 mm, for example between approximately 2 and 3 mm. The BDEs are provided in a plastic frame. The BDEs transmit charge across the electrolyte solution, inducing a strong dipole and creating positively and negatively charged radicals on alternate surfaces of the diamonds.

The electrolyte solution may be introduced into the electrolytic cell in any suitable manner so as to produce electrolyzed water composition in a continuous process or in a batch process. In the continuous process, the electrolyte solution may be introduced at a suitable flow rate, such as for example at a flow rate in the range of from 0.1 to 100 1/min, for example in the range of from 3 to 5 I/min. In the batch process, the electrolyte solution may have a flow rate of approximately 16 1/min.

A power supply was operated to apply a voltage in the range of between 1 and 1,000 Volt D.C. and a current within the range of from 1-1,000 ampere to the electrolyte solution.

The over-potential provided between the electrodes shifts the equilibrium within the electrolyte solution such that a range of 'active species' ions and molecules are produced and remain within the electrolyzed water for a significant amount of time. The term 'significant amount of time' is used herein to refer to at least 10 minutes, preferably at least 30 minutes, more preferably at least 45 minutes, for example at least 60 minutes. The combination of active molecular and ionic species together with the over-potential which supports the equilibrium confers a variable degree of pesticidal activity to the electrolyzed water composition.

The electrolytic cell preferably comprises an outlet through which the electrolyzed water composition exits the cell. The resulting electrolyzed water composition comprises a range of active molecular and ionic species which have biocidal properties.

The active molecular and ionic species include dissolved ozone. The electrolyzed water composition according to this embodiment comprises dissolved ozone at a level of approximately 50 ppm. The electrolyzed water composition according to this embodiment comprises free accessible chlorine (FAC) at a level of approximately 350 ppm.

Although the electrolyzed water composition of the present invention contains dissolved ozone at a level of approximately 50 ppm, it is to be understood that the electrolyzed water composition of the present invention may comprise any suitable level of dissolved ozone within the range of between 0.1 and 1,000 ppm. Although the electrolyzed water composition of the present invention contains FAC at a level of approximately 350 ppm, it is to be understood that the electrolyzed water composition of the present invention may comprise any suitable level of FAC within the range of between 0 and 1,000 ppm, for example between 0.01 and 350 ppm.

It is also to be understood that the electrolyzed water composition may be varied by varying one or more of: the components of the electrolyte composition, the concentration of the components within the electrolyte composition, the degree of over-potential, the current applied, or any combination thereof. In this way the biocidal properties of the electrolyzed water biocidal composition may be tailored to suit different agricultural targets, such as for example crops, pathogens, delivery mechanism, and time points, or any combination thereof. For example, the biocidal properties of the electrolyzed water biocidal composition may be tailored in relation to when the composition is to be applied, such as for example during preparation of growing beds, during sowing and/or during growing seasons.

The system may further comprise a heater arranged in use to adjust the temperature of the flow of the electrolyte feed stream and/or the electrolyte solution within the cell.

The system may comprise a control system arranged in use to control the power supply to the electrodes.

Control of the temperature of the electrolyte solution, the flow rate of the electrolyte solution feed stream, and the power supply to the electrodes may be provided by a single control system. Alternatively, these factors may be controlled by separate control systems.

Example 2 -Phytophthora infestans control on tomato plants Phytophthora infestans infected tomato plants were treated with five different treatments.

Treatment 1: untreated control (UT); Treatment 2: Revus (known pesticide); Treatment 3: Mix 1 (Comparative Example of an alternate electrolysed water 15 solution, with salts comprising NaCI at 0.30 g/I, Na2CO3 at 1.60 WI, KH2PO4 at 0.90 g/I, KNO3 at 0.80g11, CaC12-6H20 at 1.60 WI, Mg(NO3)2-61-120 at 0.80 g/l); Treatment 4: Mix 60 (Comparative Example of an alternate electrolysed water solution, with salts comprising NaCI at 0.30 WI, Na2CO3 at 1.20 g/I, KH2PO4 at 1.70 g/I, CaC12.6H20 at 1.60 g/I, Mg(NO3)2.6F120 at 1.20 g/1); and Treatment 5: composition of Example 1 (Mix 38).

The treatments were applied using a foliar spray. Each treatment group consisted of four replicates of 8 plants. Each treatment was sprayed onto the diseased plants for 30 seconds. It is to be understood that the treatment is to be applied until the treatment begins to run off from the leaves.

The results of the treatment are illustrated in Figures 1A to 1D and Figure 2.

Figures 1A to 1D are photographic images of tomato plants infected with late blight (Phytophthora infestans). The tomato plants shown in figures 1A and 1C are not treated with any pesticidal composition (treatment 1). The tomato plants shown in Figure 1B are treated with a known pesticidal composition known as Revus (treatment 2). The tomato plants shown in Figure 1D are treated with the composition of Example 1 (treatment 5).

Figures 1A and 1C show that the untreated tomato plants are diseased by the plant pathogens. A significant number of the branches and leaves are wilting and 5 diseased.

As shown in Figure 1B, the tomato plants treated with Revus (treatment 2) appear significantly more healthy than the untreated tomato plants (treatment 1) of Figure 1A. The tomato plants treated with Revus have less wilting and diseased branches and leaves. This illustrates that Revus is effective at treating at least some of the plant pathogens.

As shown in Figure 1D, the tomato plants treated with the composition of Example 1 (treatment 5) are significantly healthier than the untreated plants of Figures 1A and 1C (treatment 1), and healthier than the plants treated with Revus (treatment 2) (Figure 1 B). The tomato plants treated with the composition of Example 1 (treatment 5) appear to have very few wilting or diseased leaves and branches, and ultimately bore 35% more fruit than those treated with Revus.

The electrolyzed water composition of Example 1 therefore has an improved pesticidal effect against late blight than the known pesticide Revus.

Figure 2 illustrates the degree of crop infection or disease as represented by the percentage of late blight remaining on the tomato plants as a factor of time after treatment. It can be seen that the composition of the present invention (Treatment 5: Composition of Example 1) provides an improved pesticidal effect and significantly reduces the percentage of disease on the plants when compared with the untreated control (treatment 1) and the three other treatments. Treatment 5 (Composition of Example 1) performs better than the known pesticide (Treatment 2).

Example 3 -Treatment of Stem Bortrytis infected tomato plants The average lesion length of diseased plants was measured for five different samples of diseased tomato plants. Each sample was treated with a different treatment regime.

Treatment 1: untreated control (UT); Treatment 2: known pesticidal agent Signum; Treatment 3: Mix 1 (Comparative Example of an alternate electrolysed water solution, with salts comprising NaCI at 0.30 g/I, Na2CO3 at 1.60 g/I, KH2PO4 at 0.90 g/I, KNO3 at 0.80g11, CaCl2.6H20 at 1.60 g/I, Mg(NO3)2.6H20 at 0.80 g/1); Treatment 4: Mix 60 (Comparative Example of an alternate electrolysed water solution, with salts comprising NaCI at 0.30 g/I, Na2CO3 at 1.20 g/I, KH2PO4 at 1.70 g/I, CaCl2-6H20 at 1.60 g/I, Mg(NO3)2-6H20 at 1.20 WI); and Treatment 5: composition of Example 1 (Mix 38).

The size of the lesions on each plant sample were measured after a period of 31 10 days and 44 days after treatment. Figure 3 illustrates the results.

As shown in Figure 3, it can be seen that each of Treatment 2 to 5 results in a significant reduction in lesion size on each sample of tomato plants. Treatment 3 and Treatment 5 provide a reduction in lesion size which is at least equal to, if not greater, than the reduction provided by the known pesticidal agent, Signum (Treatment 2). Treatment 5 (Composition of Example 1) provides an improved reduction in lesion size present on the sample of plants compared to the known pesticidal agent. Treatment 5 therefore performs better than the known pesticide Signum.

Example 4 -Treatment of Sclerotinia infected carrots The average disease prevalence in carrot plants was measured for five different samples of plants which had been exposed to the Sclerotinia fungus through direct spore transfer. Each sample was identical in the number of carrot plants. The plants were sprayed with a single foliar spray until run off of the treatment solution from the leaves was observed.

Each sample was treated with a different treatment regime. Treatment 1: untreated control (UT); Treatment 2: known pesticidal agent Tebecur; Treatment 3: Mix 1 (Comparative Example of an alternate electrolysed water solution, with salts comprising NaCI at 0.30 g/I, Na2CO3 at 1.60 WI, KH2PO4 at 0.90 g/I, KNO3 at 0.80g/I, CaCl2.6H20 at 1.60 g/I, Mg(NO3)2.6H20 at 0.80 g/l); Treatment 4: Mix 60 (Comparative Example of an alternate electrolysed water 5 solution, with salts comprising NaCI at 0.30 g/I, Na2CO3 at 1.20 WI, KH2PO4 at 1.70 g/I, CaCl2-6H20 at 1.60 g/I, Mg(NO3)2-6H20 at 1.20 g/1); and Treatment 5: composition of Example 1 (Mix 38).

The prevalence of disease in each plant sample was measured after a period of 7 days, 14 days and 21 days after treatment. Figure 4 illustrates the results.

As shown in Figure 4, it can be seen that each of Treatment 2 to 5 results in a significant reduction in disease prevalence on each sample of carrot plants at each point of measurement. Treatment 5 (Composition of Example 1) provides an improved reduction in disease prevalence in the sample of plants which is almost equal to the reduction provided by treatment with the known pesticidal agent.

Example 5 -Powdery Mildew (Oidium neolycopersici) in tomatoes Groups of tomato plants (of the variety 'Juanita') infected with an inoculum of powdery mildew (as shown in Figures 5A and 5B) were treated with six different treatments. Each group consisted of 4 replicates, each having 2 plants per treatment. Each group of tomato plants was sprayed with a single spray of one of the following treatments: Treatment 1: Untreated; Treatment 2: Amistar (conventional fungicide); Treatment 3: Mix 1 (Comparative Example of an alternate electrolysed water solution, with salts comprising NaCI at 0.30 g/I, Na2CO3 at 1.60 g/I, KH2PO4 at 0.90 25 g/I, KNO3 at 0.80g/I, CaCl2.6H20 at 1.60 WI, Mg(NO3)2.6H20 at 0.80 g/1); Treatment 4: Mix 60 (Comparative Example of an alternate electrolysed water solution, with salts comprising NaCI at 0.30 g/I, Na2CO3 at 1.20 g/I, KH2PO4 at 1.70 g/I, CaCl2.6H20 at 1.60 g/I, Mg(NO3)2.6H20 at 1.20 g/1); Treatment 5: Composition of Example 1 comprising sodium salts; and Treatment 6: Composition of the present invention (K38) comprising potassium carbonate and potassium chloride in the same carbonate: chloride ratio as the composition of Example 1; and The plants were stored in a NIAB growth room using daily conditions cycle of 20 °C 5 for a 16 hour day, and then 16°C for an 8 hour night.

The plants were then scored for the degree of infection 3 weeks after the single spray treatment. The results are illustrated in Figure 6. As can be seen from Figure 6, the conventional fungicide (Amistar) provided good control of the infection. However, it can also be seen that the Composition of Example 1 provided plants having no visible signs of infection. The composition of Example 1 therefore provided an improved fungicidal effect compared to the known fungicide.

Each of the comparative Examples (Treatments 3 and 4) provided a degree of fungicidal activity. However, none of the comparative Examples provided a fungicidal effect which was as effective as either the known fungicide, Amistar or the 15 Composition of Example 1.

The plants were left for a further three weeks (a total of 6 weeks after single spray treatment) without any further treatment. The plants were then scored again for the degree of infection 6 weeks after the single spray treatment. The results are illustrated in Figure 5. As can be seen from Figures 6 and 7, the Composition of Example 1 provides a significant medium-term protective effect (Figure 6) and an ongoing protective effect (Figure 7) which has lasted for at least 6 weeks. The compositions of the present invention are believed to cause a Systemic Acquired Response inductive effect within the tomato plants.

The method of pesticidal treatment of a substrate using the compositions of the present invention have significantly reduced environmental issues compared to conventional methods. In contrast to a number of conventional methods, the compositions of the present invention contain only simple, non-toxic and food-approved salts. The compositions of the present invention are therefore more environmentally friendly than known pesticidal compositions. Furthermore, the compositions of the present invention do not leave any harmful chemical residues on treated food. The compositions of the present invention are non-toxic and non-tainting. The compositions of the present invention have a significantly improve ozone concentration compared to the level which can be achieved by injection of gaseous ozone into water. For example, the compositions of the present invention may have approximately 100 times the level which can be achieved by injection of gaseous ozone into water. As such, the compositions of the present invention may be used more frequently, during extended periods of crop production, such as for example closer to crop harvest, and without requiring any additional health and safety protection or equipment. The compositions of the present invention provide a cost effective alternative to the use of known chemical pesticides. The compositions of the present invention provide medium term protective effect and an ongoing protective effect.

It is to be understood that the Examples are illustrative of the pesticidal properties of the compositions of the present invention. It is to be understood that the compositions of the present invention may be applied in any suitable manner to an agricultural area or crop(s).

Although the Examples illustrate the use of the compositions of the present invention for the treatment of crops, it is to be understood that the compositions of the present invention may be used for the treatment of soil, and/or in any suitable industry, in particular the agricultural industry, which requires the use of pesticidal compositions. For example, the compositions of the present invention may be used to treat any equipment, such as for example irrigation systems, tanks including water tanks, and/or crop treatment equipment as well as water such as for example surface, rain and/or ground water.

Claims

Claims 1. A method for producing electrolyzed water for use in the treatment of pathogens, the method comprising: preparing an electrolyte solution comprising water, at least one carbonate salt selected from anhydrous alkali metal carbonate salts, and at least one chloride salt selected from: alkali metal chloride salts; introducing the aqueous electrolyte solution into an electrolytic cell comprising a plurality of boron-doped diamond electrodes; and operating a power supply to apply a predetermined voltage to the electrolyte solution to produce an electrolyzed water biocidal composition comprising a plurality of active molecular and ionic species having biocidal activity, in which the mixture of at least two salts of the electrolyte are selected such that the dissolved 03 concentration is in the range of from 0.1 to 1,000 ppm.
2. A method as claimed in claim 1, in which the electrolyte solution is introduced into the electrolytic cell in a continuous or batch process manner.
3. A method as claimed in either of claims 1 and 2, in which the at least one carbonate salt is selected from anhydrous sodium carbonate and/or anhydrous potassium carbonate.
4. A method as claimed in any preceding claim, in which the at least one chloride salt is selected from sodium chloride and potassium chloride.
5. A method as claimed in any preceding claim, in which the predetermined voltage is in the range of between about 1 and 1000 volts DC.
6. A method as claimed in claim 5, in which the power supply has a current in the range of between about 1 and 1000 ampere.
7. An apparatus for producing electrolyzed water composition for use in treatment of plants to reduce pathogens, the apparatus comprising: a reservoir comprising an electrolyte solution comprising water, at least one carbonate salt selected from: anhydrous alkali metal carbonates, and at least one chloride salt selected from: alkali metal chloride salts; an electrolytic flow cell in fluid communication with the reservoir to receive a feed stream comprising the aqueous electrolyte solution; and a plurality of boron-doped diamond electrodes located within the electrolytic cell and arranged in use to be connected to a power supply.
8. An electrolyte solution comprising at least one carbonate salt selected from: anhydrous alkali metal carbonates, and at least one chloride salt selected from: alkali metal chloride salts.
9. An electrolyte solution as claimed in claim 8, in which the electrolyte solution comprises: at least one carbonate salt selected from anhydrous potassium carbonate and/or anhydrous sodium carbonate; and at least one chloride salt selected from potassium chloride and/or sodium chloride.
10. An electrolyzed water composition obtainable by a method as claimed in any one of claims 1 to 6.
11. Use of the electrolyzed water composition as claimed in claim 10 as a pesticidal agent.
12. An applicator for treating agricultural crops, in which the applicator comprises a reservoir comprising an electrolyzed water composition as claimed in claim 10, and an outlet in fluid communication with the reservoir.
13. An applicator as claimed in claim 12, in which the applicator is selected from one or more of: a nebuliser, a fogging mist applicator, a jet spray applicator, a spray applicator, or an irrigation system, or any combination thereof.