ANTIMICROBIAL COMPOSITIONS AND METHODS FOR TREATING PLANT DISEASES

Abstract

An antimicrobial composition for treating plant diseases includes a solvent into which an antibiotic is substantially dissolved to achieve a concentration of the antibiotic sufficient to treat a bacterial infection in a plant. An acid is added to the solvent at a concentration sufficient to generate a pH in a range of 1.5 to less than 4.0. The antimicrobial can be delivered systemically to a plant, thereby allowing the antibiotic to treat a bacterial disease inflicting the plant.

Claims

1. An antimicrobial composition for treating plant diseases comprising: a solvent; an antibiotic substantially dissolved in the solvent at a concentration sufficient to treat a bacterial infection in a plant, the antibiotic comprising oxytetracycline; an acid present in the solvent at a concentration sufficient to generate a pH in a range of 1.8 to 2.5; and the antimicrobial composition being configured for injection into a plant, wherein the antibiotic is configured for treating a bacterial disease inflicting the plant.

2. The antimicrobial composition of claim 1, wherein the solvent comprises water.

3. The antimicrobial composition of claim 1, wherein the antibiotic has a concentration of 500 to 50,000 parts per million.

4. The antimicrobial composition of claim 1, wherein the antibiotic has a concentration of 500 to 25,000 parts per million.

5. The antimicrobial composition of claim 1, wherein the antibiotic has a concentration of 500-12,000 parts per million.

6. The antimicrobial composition of claim 3, wherein the acid comprises an inorganic acid.

7. The antimicrobial composition of claim 6, wherein the acid comprises hydrochloric acid.

8. The antimicrobial composition of claim 3, wherein the antimicrobial composition is configured for injection into the vascular network of a tree or vine.

9. The antimicrobial composition of claim 1, wherein: the solvent comprises water; the antibiotic has a concentration of 500-12,000 parts per million; the acid comprises hydrochloric acid; and the antimicrobial composition is configured for injection into the vascular network of a tree or vine.

10. The antimicrobial of claim 9, wherein the antimicrobial composition has a pH of 2.

11. The antimicrobial of claim 1, wherein the antimicrobial composition has a pH of 2.

Description

(I) BRIEF DESCRIPTION OF THE DRAWING

[0013] The disclosure will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

[0014] FIG. 1 is a representative picture of a Valencia orange tree treated by injection with a solution of oxytetracycline acidified to pH 2.

[0015] FIG. 2 is a representative picture of a Valencia orange tree treated by foliar spraying with an unacidified oxytetracycline solution.

[0016] FIG. 3 is a representative picture of a Valencia orange tree treated by injection with a solution of streptomycin acidified to pH 2.

[0017] FIG. 4 is a representative picture of a Valencia orange tree treated by foliar spraying with an unacidified streptomycin solution.

[0018] FIG. 5 is a representative picture of an untreated Valencia orange tree.

[0019] FIG. 6 is a flow diagram for a method of generating an acidified antibiotic solution and its use in treating a bacterial infection in a plant according to an embodiment of the disclosure.

(J) DETAILED DESCRIPTION OF THE INVENTION

[0020] With reference now to FIGS. 1-6, a new antimicrobial composition embodying the principles and concepts of an embodiment of the disclosure and a method will be described.

[0021] The antimicrobial composition generally comprises a solvent into which an antibiotic is substantially dissolved to achieve a concentration of the antibiotic sufficient to treat a bacterial infection in a plant. The solvent generally comprises water, but also may include cosolvents, such as, but not limited to, alcohols, dimethyl sulfoxide, and the like. The antibiotic may comprise a tetracycline, an aminoglycoside, or the like, and thus be configured to treat a candidatus liberibacter africanus, a candidatus liberibacter americanus, or a candidatus liberibacter asiaticus infection in a citrus tree. The tetracycline antibiotic may comprise tetracycline, chlortetracycline, oxytetracycline, demeclocycline, lymecycline, meclocycline, methacycline, minocycline, rolitetracycline, doxycycline, tigecycline, eravacycline, sarecycline, oromadacycline, or the like. The aminoglycoside antibiotic may comprise kanamycin A, amikacinm, tobramycin, dibekacin, gentamicin, sisomicin, netilmicin, neomycin B, neomycin C, neomycin E, streptomycin, plazomicin, or the like. The antibiotic may have a concentration of 500 to 50,000 parts per million. The antibiotic may have a concentration of 500 to 25,000 parts per million. The antibiotic may have a concentration of 500-12,000 parts per million.

[0022] An acid is present in the solvent at a concentration sufficient to generate a pH in a range of 1.5 to less than 4.0. The acid may be present at a concentration sufficient to generate a pH in a range 1.8-2.5. The acid may comprise an inorganic acid, although the present invention also anticipates the acid comprising an organic acid, or a combination of an inorganic acid and an organic acid. The acid may comprise hydrochloric acid, phosphoric acid, nitric acid, acetic acid, citric acid, or the like.

[0023] The antimicrobial composition is configured for systemic delivery to a plant so that the antibiotic is configured to treat a bacterial disease inflicting the plant. The antimicrobial composition may be configured for injection into the vascular network of a tree or vine.

[0024] The present invention anticipates a method (FIG. 6) of generating an acidified antibiotic solution and its use in treating a bacterial infection in a plant. The method comprises a first step of adding an antibiotic to a solvent in an amount sufficient to generate a first solution having a concentration of the antibiotic sufficient to treat a bacterial infection in a plant. A second step of the method is titrating the first solution using an acid to generate a second solution having a pH of from 1.5 to less than 4.0. A third step of the method is drilling a hole into a trunk of a tree or vine. A fourth step of the method is injecting the second solution into a vascular network of the tree or vine. As will be apparent to those of ordinary skill in the art, the order of addition of the antibiotic and the acid to the solvent can be reversed upon determination of the quantities of each required to achieve a desired pH of the antibiotic solution.

[0025] Provided below are detailed examples of the antimicrobial compositions for treating plant diseases and methods for their use in treating bacterial infections in plants. These examples should not be viewed as limiting regarding compositions, methods of preparation and use, or plant species.

I. Definitions

[0026] Tree Vigor Ratings: 1 = Lowest Vigor; 5 = Highest Vigor. LSD stands for least significant difference and C.V. stands for Coefficient of Variance. “a” denotes the corresponding value is significantly different from any other value that does not contain the letter “a”. Similarly, “b” denotes the corresponding value is significantly different from any other value that does not contain the letter “b”.

II. Valencia Orange Tree Trials

A. Oxytetracycline

[0027] Table 1 below provides the results this study. For Treatment 1, a 5,500 ppm solution of oxytetracycline (HCl salt, >95%) was prepared using distilled water. This solution then was acidified to pH 2 using hydrochloric acid. Each tree (n = 9) was injected with 50 mL of the solution, delivering 0.275 grams of oxytetracycline.Math.HCl. For Treatment 2, 2.5 g of oxytetracycline (HCl salt, >95%) was dissolved in 2 gallons of water. The resultant solution was sprayed onto the foliage of the trees at a rate of 1 quart (0.3125 g oxytetracycline-HCl) per tree (n = 9). Vigor ratings were performed 60 days after application of treatments.

[0028] Trial conclusions: Solutions of oxytetracycline acidified to pH 2 and delivered by trunk injection were more effective than solutions of unacidified oxytetracycline applied to foliage by spraying.

TABLE-US-00001 Trt # Treatment Vigor Rating (1-5) 1 Oxytetracycline - HCl solution, injected 3.39 a 2 Oxytetracycline - aqueous solution, sprayed 2.67 b LSD P=0.05 0.477

B. Streptomycin

[0029] Table 1 below provides the results this study. For Treatment 1, a 5,500 ppm solution of streptomycin (sulfate salt, >98%) was prepared using distilled water. This solution then was acidified to pH 2 using hydrochloric acid. Each tree (n = 9) was injected with 50 mL of the solution delivering 0.275 g streptomycin.Math.SO.sub.4. For Treatment 2, 4.12 g of streptomycin (sulfate salt, >98%) was dissolved in 2 gallons of water. The resultant solution was sprayed onto the foliage of the trees at a rate of 1 quart (0.515 g streptomycin.Math.SO.sub.4) per tree (n=9). Vigor ratings were performed 60 days after application of treatments.

[0030] Trial conclusions: Solutions of streptomycin acidified to pH 2 and delivered by trunk injection were more effective than solutions of unacidified streptomycin applied to foliage by spraying.

TABLE-US-00002 Trt # Treatment Vigor Rating (1-5) 1 Streptomycin - HCl solution, injected 3.61 a 2 Streptomycin - aqueous solution, sprayed 2.94 b LSD P=0.05 0.512

[0031] Table 3 represents a working example on dosing a desired amount of antimicrobial agent into a tree or vine. Factors that could alter the dosage include overall plant health, i.e., a decline in vascular biomass caused by the pathogen, hedging and pruning, and environmental factors, such as temperature, moisture, and stress.

TABLE-US-00003 Trunk Diameter (inches) Antibiotic (PPM) Volume Injected (mL) Antibiotic (g per Tree/Vine) 1.25 - 1.75 550 - 1,100 25 0.014 - 0.028 1.75 - 2.12 550 - 2,200 50 0.027 - 0.11 2.12 - 3.00 5,500 - 11,000 25 0.14 - 0.28 3.00 - 4.25 5,500 - 11,000 50 0.28 - 0.55 4.25 - 6.00 5,500 - 11,000 100 0.55 - 1.10 > 6.00 5,500 - 11,000 200 1.10 - 2.20

[0032] Generally, the volume of treatment injected would be proportional to a diameter of a trunk of a tree. Trees having vascular networks damaged by disease would be treated at lower concentrations to prevent phytotoxicity. As the trees recover, the concentration can be increased to mitigate risk of reinfection.

[0033] Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity and understanding, it will be readily apparent, in light of the teachings of this invention, that certain changes and modifications may be made thereto without departing from the spirit or scope of the following claims.

[0034] Therefore, the foregoing is considered as illustrative only of the principles of the disclosure. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the disclosure to the exact compositions and methods of use, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the disclosure. In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the elements is present, unless the context clearly requires that there be only one of the elements.