U.S. patent application number 15/785544 was filed with the patent office on 2018-04-19 for soil treatment.
This patent application is currently assigned to PeroxyChem LLC. The applicant listed for this patent is PeroxyChem LLC. Invention is credited to Weidong AN, Jose M. LOPEZ MARTINEZ, Fernando PUENTE DE VERA, John M. ROVISON.
Application Number | 20180103638 15/785544 |
Document ID | / |
Family ID | 61902068 |
Filed Date | 2018-04-19 |
United States Patent
Application |
20180103638 |
Kind Code |
A1 |
PUENTE DE VERA; Fernando ;
et al. |
April 19, 2018 |
SOIL TREATMENT
Abstract
The present invention relates to compositions and formulations
for soil disinfection against a wide spectrum of plant pathogens
and pests. More particularly, the formulation comprising (i)
peracids, such as peracetic acid and an (ii) anionic surfactant,
such as capryleth-9 carboxylic acid is synergistically effective in
treatment of soil to control plant parasitic nematodes and
soil-borne plant pathogens such as bacteria, spores and fungi.
Inventors: |
PUENTE DE VERA; Fernando;
(Zaragoza, ES) ; LOPEZ MARTINEZ; Jose M.;
(Barcelona, ES) ; ROVISON; John M.; (Sanborn,
NY) ; AN; Weidong; (Williamsville, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PeroxyChem LLC |
Philadelphia |
PA |
US |
|
|
Assignee: |
PeroxyChem LLC
Philadelphia
PA
|
Family ID: |
61902068 |
Appl. No.: |
15/785544 |
Filed: |
October 17, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62409525 |
Oct 18, 2016 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A01N 37/16 20130101;
A61L 2/0088 20130101; A01N 59/00 20130101; A61L 2/186 20130101;
A01M 17/002 20130101; A01N 37/16 20130101; A01N 59/00 20130101;
A01N 37/16 20130101; A01N 25/30 20130101; A01N 59/00 20130101; A01N
59/00 20130101; A01N 25/30 20130101 |
International
Class: |
A01N 37/16 20060101
A01N037/16; A01M 17/00 20060101 A01M017/00 |
Claims
1. An aqueous composition comprising a peracid and a
polyoxyethylene alkylether carboxylic acid or a salt thereof.
2. The composition of claim 1, wherein the peracid is peracetic
acid.
3. The composition of claim 1, wherein the peracetic acid is an
aqueous equilibrium solution comprising a weight ratio of peracetic
acid:hydrogen peroxide between 1:0.01 to 1:14 and a weight ratio of
peracetic acid:acetic acid between 1:0.2 to 1:19.
4. The method of claim 1, wherein the peracetic acid concentration
is from about 3000 ppm to about 25,000 ppm.
5. The composition of claim 1, wherein the polyoxyethylene
alkylether carboxylic acid concentration is from about 250 ppm to
about 25,000 ppm.
6. A method of reducing the level of a pathogenic microorganism in
an agricultural medium, the method comprising applying the aqueous
composition of claim 1 to the agricultural medium at a
concentration and for a time sufficient to reduce the levels of the
microorganism in the agricultural medium.
7. The method of claim 6, wherein the pathogenic microorganism is
selected from the group consisting of nematodes, bacteria and
fungi.
8. The method of claim 7, wherein the nematode is selected from the
group consisting of root knot nematodes, cyst nematodes, root
lesion nematodes, and burrowing nematodes.
9. The method of claim 7, wherein the bacteria comprises a spore
forming bacteria.
10. The method of claim 6, wherein the agricultural medium
comprises soil, sand, or a synthetic growth medium.
11. The method of claim 6, wherein the contacting step comprises
spraying, drenching, injecting, sprinkling or infusing the
composition into the agricultural medium.
12. The method of claim 6, wherein the aqueous solution is applied
at about 1.5 mL/cm.sup.2 of agricultural medium.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.
119(e)(1) from U.S. Provisional Application Ser. No. 62/409,525,
filed Oct. 18, 2016, the contents of which are incorporated herein
by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to compositions and methods
for soil disinfection. The compositions and methods are useful
against a variety of plant pathogens, including nematodes,
bacteria, and fungi.
BACKGROUND OF THE INVENTION
[0003] Historically, methyl bromide (CH.sub.3Br) had been the most
widely used and most universal fumigant in the world. It is known
for being extremely effective as a nematicide, insecticide,
fungicide, and herbicide. Methyl bromide has been used extensively
as a soil fumigant, a commodity quarantine treatment for exports
and imports, as a pesticide on numerous crops, and as a structural
fumigant applied to building surfaces. However, methyl bromide has
contributed to the depletion of the ozone layer in the
stratosphere. In accord with the Montreal Protocol, the import and
manufacture of methyl bromide in the United States and other
developed countries was banned in 2005. For developing countries,
the reductions were more gradual and the phase-out was delayed
until 2015.
[0004] Various compounds such as 1,3-dichloropropene, chloropicrin,
metam sodium, and methyl iodide have been identified as
alternatives to methyl bromide. While the alternative compounds do
not cause depletion of stratospheric ozone, they all have
limitations in activity or versatility as soil fumigants. They can
be less effective than methyl bromide. They are commonly applied as
mixtures of two or more of the individual compounds or in
sequential applications in order to produce a broader spectrum
product, resulting in reduced efficiency and increased costs for
the user. Moreover, the toxicities associated with many alternative
compounds present potential risks of worker exposure, contamination
of crops and other plants with chemical residues, and environmental
hazards such as ground water contamination.
[0005] Organic peracids, such as peracetic acid (PAA) are potent
biocides. They have had limited utility as soil sterilants, in
part, because the relatively high concentration of organic matter
in soil may inactivate the peracids.
[0006] U.S. Pat. No. 5,168,655 discloses an aqueous solution
comprising peracetic acid being made in-situ by mixing acetic acid,
hydrogen peroxide, 2,6-pyridine dicarboxylic acid, dodecyl benzene
sulphonic acid, and water. The solution is used in an irrigation
system to partially control bacteria, fungal, spores, yeast, and
molds in hydroponic substrates. U.S. Pat. No. 5,168,655 requires
that the substrate contain only a minimal amount of organic matter
because excessive amounts of organic matter, such as those in soil,
are believed to inactivate the peracetic acid. Aromatic alkyl
sulphonic acid, specifically odecyl benzene sulphonic acid, is
disclosed as a wetting agent in the solution in U.S. Pat. No.
5,168,655.
[0007] EP 0035800 discloses an aqueous solution containing hydrogen
peroxide and/or peracids having 1 to 4 carbon as soil treatment
agent to control phytopathogenic harmful organisms, such as fungi,
bacteria, and nematodes.
SUMMARY OF THE INVENTION
[0008] The present invention relates to and aqueous composition
comprising a peracid and a polyoxyethylene alkylether carboxylic
acid or a salt thereof. The peracid can be peracetic acid. The
peracetic acid can be an aqueous equilibrium solution comprising a
weight ratio of peracetic acid:hydrogen peroxide between 1:0.01 to
1:14 and a weight ratio of peracetic acid:acetic acid between 1:0.2
to 1:19. The peracetic acid concentration can be from about 3000
ppm to about 25,000 ppm. The polyoxyethylene alkylether carboxylic
acid concentration can be from about 250 ppm to about 25,000 ppm.
Also provided is a method of reducing the level of a pathogenic
microorganism in an agricultural medium by contacting the
agricultural medium with a composition comprising a peracid and a
polyoxyethylene alkylether carboxylic acid or a salt thereof. The
peracid can be peracetic acid. The pathogenic microorganism can be
a nematode, bacteria, or fungus. The agricultural medium can
include soil, sand, or a synthetic growth medium. The agricultural
medium can be contacted with the composition by spraying,
drenching, injecting, sprinkling, or infusing the composition into
the agricultural medium. In some embodiments, the aqueous solution
is applied at about 1.5 mL/cm.sup.2 of agricultural medium.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0009] This description of preferred embodiments is intended to be
read in connection with the accompanying drawings, which are to be
considered part of the entire written description of this
invention. The drawing figures are not necessarily to scale and
certain features of the invention may be shown exaggerated in scale
or in somewhat schematic form in the interest of clarity and
conciseness. In the description, relative terms such as
"horizontal," "vertical," "up," "down," "top" and "bottom" as well
as derivatives thereof (e.g., "horizontally," "downwardly,"
"upwardly," etc.) should be construed to refer to the orientation
as then described or as shown in the drawing figure under
discussion. These relative terms are for convenience of description
and normally are not intended to require a particular orientation.
Terms including "inwardly" versus "outwardly," "longitudinal"
versus "lateral" and the like are to be interpreted relative to one
another or relative to an axis of elongation, or an axis or center
of rotation, as appropriate. Terms concerning attachments, coupling
and the like, such as "connected" and "interconnected," refer to a
relationship wherein structures are secured or attached to one
another either directly or indirectly through intervening
structures, as well as both movable or rigid attachments or
relationships, unless expressly described otherwise. The term
"operatively connected" is such an attachment, coupling or
connection that allows the pertinent structures to operate as
intended by virtue of that relationship. When only a single machine
is illustrated, the term "machine" shall also be taken to include
any collection of machines that individually or jointly execute a
set (or multiple sets) of instructions to perform any one or more
of the methodologies discussed herein. In the claims,
means-plus-function clauses, if used, are intended to cover the
structures described, suggested, or rendered obvious by the written
description or drawings for performing the recited function,
including not only structural equivalents but also equivalent
structures.
[0010] The present invention is directed to formulations for
treatment of soil to control plant parasitic nematodes and
soil-borne plant pathogens, for example, bacteria and fungi. The
formulations include (i) peracids, such as peracetic acid and (ii)
anionic surfactants, such as capryleth-9 carboxylic acid.
[0011] Peracetic acid is typically employed in the form of an
aqueous equilibrium mixture of acetic acid (AA), hydrogen peroxide
(H.sub.2O.sub.2) and peracetic acid (PAA). The weight ratios of
these components may vary greatly, depending upon the particular
grade of PAA employed. Among the grades of PAA which may be
employed are those having a weight ratio of PAA:hydrogen peroxide
between 1:0.01 to 1:14 and a weight ratio of PAA:acetic acid
between 1:0.2 to 1:19. Commercially available peracetic acid
solutions include 5% PAA with 22% H.sub.2O.sub.2 and 10.5% AA, 15%
PAA with 10% H.sub.2O.sub.2 and 35% AA, 15% PAA with 23%
H.sub.2O.sub.2 and 16% AA, 22% PAA with 10% H.sub.2O.sub.2 and 35%
AA, and 35% PAA with 6.5% H.sub.2O.sub.2 and 40% AA.
[0012] The anionic surfactant can be a polyoxyethylene alkylether
carboxylic acid, or a related anionic surfactant, including, for
example, polyoxyethylene octyl ether carboxylic acid,
polyoxyethylene(8) octyl ether carboxylic acid, polyoxyethylene(10)
oleyl ether carboxylic acid, polyoxyethylene(10) lauryl ether
carboxylic acid, polyoxyethylene(3) lauryl ether carboxylic acid,
polyoxyethylene(5) lauryl ether carboxylic acid, polyoxyethylene(7)
lauryl ether carboxylic acid, polyoxyethylene(2) oleyl ether
carboxylic acid, polyoxyethylene(5) oleyl ether carboxylic acid,
polyoxyethylene(9) oleyl ether carboxylic acid, and salts of above
said polyoxyethylene alkylether carboxylic acids in sodium,
potassium, or other cation forms. In some embodiments, the anionic
surfactant is polyoxyethylene alkylether carboxylic acid, which is
also known as Capryleth-9 Carboxylic Acid (denoted as C9CA).
[0013] Thus, the compositions of the invention can include a
peracid, for example peracetic acid, and an anionic surfactant, for
example, capryleth-9-carboxylic acid (C9CA). The peracid and the
anionic surfactant can be diluted with water to the desired
concentrations and combined at the point of use. Alternatively, or
in addition, the peracid and the anionic surfactants can be
combined to form a mixture and the mixture can be diluted with
water before use. The peracid and the anionic surfactant can be
combined and stored before use or they can be combined and used
directly.
[0014] The compositions employed in the formulation of the
invention can further include or exclude sequestriants such as
dipicolinic acid and 1-hydroxyethylidene-1,1,-diphosphonic acid, as
well as other ingredients such as mineral acid catalysts (sulfuric,
nitric, or phosphoric acids); and short chain fatty esters (C6-C12)
forming mixed peracids in solution.
[0015] In addition, the compositions employed in the formulation of
the invention may further include or exclude one or more additional
oxidants selected from the group consisting of chloroperbenzoic
acid, perheptanoic acid, peroctanoic acid, perdecanoic acid,
performic acid, percitric acid, perglycolic acid, perlactic acid
and perbenzoic acid.
[0016] The compositions are diluted into water before use, and the
diluted formulation can be applied using application techniques and
equipment for soil fumigants in liquid form, such as trench
applications, handgun applications, shank (chisel) applications,
sweep or blade applications, drench application, and
chemigation.
[0017] The present formulations may be used to control plant
parasitic nematodes and soil-borne plant pathogens of bacteria and
fungi. Exemplary plant parasitic nematodes include root knot
nematodes such as Meloidogyne hapla, Meloidogyne incognita,
Meloidogyne enterolobii and Meloidogyne mayaguensis; cyst nematodes
such as soybean cyst nematodes (Heterodera glycines); potato cyst
nematodes (Globodera pallida and G. rostochiensis) and cereal cyst
nematodes (Heterodera avenae and H. filipjevi); root lesion
nematodes such as (Pratylenchus spp., including P. penetrans, P.
thornei, P. neglectus, P. zeae, P. vulnus and P. coffeae; and the
burrowing nematode, Radopholus similis.
[0018] Exemplary soil bacteria include Bacillus species, for
example Bacillus mycoides. Exemplary soil fungi include Aspergillus
species, for example Aspergillus niger.
[0019] The following Examples are presented to offer further
illustration of the present invention, but are not intended to
limit the scope of the invention in any manner whatsoever.
EXAMPLES
Example 1
[0020] Peracetic acid formulations were evaluated for nematocidal
and bactericidal activity. Formaldehyde was used as a positive
control. The test conditions are described below and the results
are summarized in Tables 1, 2, and 3.
[0021] Test method: A peracetic acid stock solution containing 5%
PAA and 22% H.sub.2O.sub.2 (VigorOx.RTM. from PeroxyChem, LLC) was
used for methods that specified 1750 ppm PAA. A peracetic acid
stock solution containing 15% PAA and 10% H.sub.2O.sub.2 (VigorOx
SP-15) was used for methods that specified 3525 ppm PAA. A stock
solution of formaldehyde (37% in 10-15% methanol) was used to
prepare a 1% aqueous solution of formaldehyde (with about 0.3%
methanol).
[0022] Solutions were applied as the soil drench with an
application volume of 12 kL/ha. The Test Medium was: pasteurized
50:50 Loamy sand or pasteurized sand. The efficacy of PAA was
evaluated in three different Greenhouse Test Assays: 1) the Tomato
Root-knot Galling Index Assay using the nematode species
Meloidogyne incognita and Meloidogyne hapla; 2) the Root-knot
Nematode Egg Hatch Assay using the nematode species Meloidogyne
incognita and Meloidogyne hapla; and 3) assay of levels of soil
bacteria using Bacillus mycoides.
[0023] The Root-knot Nematode Egg Hatch Assay was carried out
essentially as follows. Eggs were collected from roots of infected
tomato plants. To release the eggs, the egg masses were placed in a
solution of sodium hypochlorite and manually shaken. The solution
was centrifuged and the eggs washed with distilled water. Eggs were
kept in the dark until needed for the experiments and used in the
same day of collection. The experiments were performed in pots
filled with pasteurized soil inoculated with about several
thousands of individual eggs and then drenched with each treatment
solution and controls. The treated soils were covered and incubated
for the time periods indicated below. Following the incubation
period, the soils were transferred to collect hatched J2 (second
stage juveniles). The collected material was observed under the
microscope and the number of J2 counted.
[0024] The results of the Root Knot Galling Index Assay are shown
in Table 1. Seedlings were inoculated and cultivated for 28 days.
Seedlings were then treated with either formaldehyde or 1750 ppm
PAA for 27 days. Seedlings were harvested and the number of galls
was determined. The Galling Index was on a scale of 0 to 10, where
0=no galling and 10=severe galling. A Galling Index of 3 or less is
considered as commercial level control. As shown in Table 1, PAA
alone at a dosage of 1750 ppm PAA applied as a soil drench to cells
in the greenhouse provided only a modest reduction in the Galling
Index that did not approach a commercial level of control.
TABLE-US-00001 TABLE 1 Effect of PAA on Tomato Root-knot Nematode
Galling Index Inoculation Formaldehyde VigorOx at Treatment control
at 1% 1750 ppm PAA Root-knot Galling 8.5 2 7 Index
[0025] The results of the Root Knot Nematode Egg Hatch Assay are
shown in Table 2. Seedlings were inoculated and cultured in
pasteurized Pemberton soil for 14 days. Seedlings were then treated
with either formaldehyde, 1750 ppm PAA or 3525 ppm PAA for 13 days.
Nematode eggs were extracted from infected roots and their ability
to hatch was evaluated. As shown in Table 2, treatment of soil with
3525 ppm PAA resulted in a 51% reduction of the J2 (second stage
juvenile) population relativity to control. Treatment of soil with
1750 ppm PAA did not reduce the J2 population relative to untreated
controls. Treatment with 1% formaldehyde resulted in a 78%
reduction relative to untreated controls.
TABLE-US-00002 TABLE 2 Effect of PAA Formulations on Root-knot
Nematode Egg Hatch Formaldehyde VigorOx at VigorOx SP-15 at
Treatment at 1% 1750 ppm PAA 3525 ppm PAA.sup.[1] % Reduction of 78
0 51 J2 population
[0026] The formulations were also assayed for the ability to reduce
soil bacteria as shown in Table 3. Soil was inoculated with
Bacillus mycoides, incubated for five days and then treated with
formaldehyde or 1750 PPA for four days. Bacteria were collected
from soil and their levels were evaluated based on colony forming
units. As shown in Table 3, treatment of soil with 1750 ppm PAA
resulted in a 47.5% reaction of colony forming units (CFU's)
relative to control. Treatment of soil with 1% formaldehyde
resulted in a 42.5% reduction of colony forming units (CFU's)
relative to control.
TABLE-US-00003 TABLE 3 Effect of PAA on Bacteria in Soil
Formaldehyde VigorOx at Treatment at 1% 1750 ppm PAA % Reduction in
42.5 47.5 population (CFU's)
Example 2
[0027] Peracetic acid formulations were evaluated for nematocidal
activity either alone or in combination with C9CA. Formaldehyde was
used as a positive control.
[0028] Test method: A peracetic acid stock solution containing 15%
PAA and 10% H.sub.2O.sub.2 (VigorOx SP-15) was used for methods
that specified 3750, 5000, 7500, 10000 ppm PAA. Capryleth-9
carboxylic acid (C9CA) was used at concentrations of 5000 and 10000
ppm. A stock solution of formaldehyde (37% in 10-15% methanol) was
used to prepare a 1% aqueous solution of formaldehyde. The final
methanol concentration was about 0.3%.
[0029] Solutions were applied as a soil drench with an application
volume of 12 kL/ha. The Test Medium was pasteurized Pemberton loamy
soil, sand or pasteurized sand. The efficacy of PAA was evaluated
with the Root-Knot Nematode Egg Hatch Assay using the nematode
species Meloidogyne incognita and Meloidogyne hapla.
[0030] The results of the Root Knot Nematode Egg Hatch Assay are
shown in Table 4. Seedlings were inoculated and cultured for 22
days and then treated for 21 days with either PAA alone at various
concentrations, C9CA alone at various concentrations, or a
combination of PAA and C9CA. Nematode eggs were extracted from
infected roots and their ability to hatch was evaluated.
TABLE-US-00004 TABLE 4 Effect of PAA and C9CA on Root-knot Nematode
Egg Hatch % Reduction of Treatment J2 Population Formaldehyde At 1%
60 Vigorox SP-15 3500 ppm PAA 38 5000 ppm PAA 20 7500 ppm PAA 50
10000 ppm PAA 28 C9CA 5000 ppm 0 10000 ppm 10 Vigorox SP-15 + 5000
ppm PAA + 5000 ppm C9CA 40 C9CA 10000 ppm PAA + 10000 ppm C9CA 60
Note: 22 days after inoculation; 21 days after treatment.
[0031] As shown in Example 2, PAA alone at a dosage between 3500 to
10000 ppm provided a moderate reduction in J2 nematode population
in soil, which is consistent with the result in Example 1. C9CA
provided minimal nematicidal activity when used alone at either
5000 ppm or 10000 ppm. When PAA and C9CA were used together, the
effect on reduction of nematode population was substantially
greater than the effect of either agent alone. PAA alone at 5000
ppm produced a 20% reduction in egg hatch. C9CA alone did not
reduce the nematode population. But, the combination of PAA at 5000
ppm and C9CA at 5000 ppm resulted in a 40% reduction in the
nematode population, as measured by Egg Hatch levels. This effect
was also noted at higher concentrations of the agents. PAA alone at
10,000 ppm produced a 28% reduction nematode population. C9CA alone
at 10,000 ppm produced a 10% reduction in nematode population. But,
the combination of PAA at 10,000 ppm and C9CA at 10,000 ppm
resulted in a 60% reduction in the nematode population, a reduction
that was similar to that observed with the more toxic formaldehyde
treatment. This synergistic effect was unexpected.
Example 3
[0032] Peracetic acid formulations were evaluated for nematocidal
activity either alone or in combination with C9CA. Distilled water
was used as a control in order to calculate the percentage of egg
hatch that occurred in untreated soil.
[0033] Test method: A peracetic acid stock solution containing 15%
PAA and 10% H.sub.2O.sub.2 (VigorOx SP-15) was used for methods
that specified 3500 and 20,000 ppm PAA. Capryleth-9 carboxylic acid
(C9CA) was used at concentrations of 250 and 10000 ppm.
[0034] Solutions were applied as a soil drench with an application
volume of 1 ml/cm.sup.2. The Test Medium was pasteurized sand-loam
soil. The efficacy of PAA was evaluated with the Root-knot Nematode
Egg Hatch Assay using the nematode species Meloidogyne incognita
and Meloidogyne hapla.
[0035] The viability of the root-knot nematodes eggs used for each
set of experiments in this example was also evaluated. Eggs were
incubated with the different solutions in glass dishes in the dark
at 25.degree. C. They were observed daily under the microscope to
confirm that the eggs were viable and able to hatch in water after
18 hr/24 hr of incubation. These observations confirmed that the
eggs used for each set of soil experiments were viable.
[0036] The results of the Root Knot Nematode Egg Hatch Assay are
shown in Table 5. Seedlings were inoculated and cultured for 22
days and then treated for 21 days with either PAA alone at various
concentrations, C9CA alone at various concentrations, or a
combination of PAA and C9CA. Nematode eggs were extracted from
infected roots and their ability to hatch was evaluated.
TABLE-US-00005 TABLE 5 Effect of PAA and C9CA on Root-knot Nematode
Egg Hatch % Egg Treatment Hatching Distilled water 100 VigorOx
SP-15 20000 ppm PAA 53 C9CA 250 ppm 66 VigorOx SP-15 + 3500 ppm PAA
+ 250 ppm C9CA 45 C9CA 200000 ppm PAA + 10000 ppm C9CA 11
[0037] As shown in Table 5, soil treatment with PAA alone at 20,000
ppm had an inhibitory effect on egg hatching. Soil treatment with
PAA alone at 20,000 ppm reduced egg hatching to 53% of distilled
water treated control levels. Soil treatment with C9CA alone also
had a modest inhibitory effect on egg hatching. Soil treatment with
C9CA alone at 250 ppm reduced egg hatching to 66% of distilled
water treated control levels. Consistent with the results shown in
Example 2, when PAA and C9CA were used together, the effect on
reduction of nematode population was substantially greater than the
effect of either agent alone. Moreover, the inhibitory effect was
dose-dependent. Soil treatment with 3500 ppm PAA+250 ppm C9CA
reduced egg hatching to 45% of distilled water treated control
levels. Soil treatment at higher doses, (20000 ppm PAA+10000 ppm
C9CA) reduced the percentage of egg hatching to only 11% of
distilled water treated controls. This synergistic effect was
unexpected.
[0038] Example 4
Peracetic acid formulations were evaluated for sporicidal
activity.
[0039] Test method: A peracetic acid stock solution containing 15%
PAA and 10% H.sub.2O.sub.2 (VigorOx SP-15) was used for methods
that specified 3525 ppm PAA. Deionized water was used as a
control.
[0040] Solutions were applied as the soil drench with an
application volume of 1.5 ml/cm.sup.2. The Test Medium was
pasteurized Pemberton soil. The spore inoculum was Bacillus
subtilis ATCC 19659. Spores were counted as follows: Soil was
pasteurized to remove background microbial content. The soil was
distributed into test cells. Concentrated Bacillus subtilis ATCC
19659 spore suspension was diluted in Butterfield's buffer and used
as the inoculum in this test. For titer determination, the inoculum
was diluted in Butterfield's buffer and plated on Petrifilm APC. In
order to test for antimicrobial efficacy following treatments, soil
was scooped from the cell and measured into a sterile plastic
centrifuge tube. Deionized water was then added to each soil
sample. The tubes were then capped, shaken to suspend soil, and
vortexed at maximum speed using the lab vortex. The samples were
allowed to settle for several seconds, and then 2 mL of fluid was
removed from the tube. One ml of the removed sample was diluted in
9 mL Butterfield's buffer. The remainder of the removed sample was
plated onto Petrifilm APC. The diluted sample was further serially
diluted and plated on APC. The plates were all incubated at
30.+-.2.degree. C. for 2-5 days and then colonies on the plates
were counted.
[0041] The results of the sporicidal assay are shown in Table 6. As
shown in Table 6, no bacterial spores capable of giving rise to
viable colonies were recovered after both short (1 hour) and longer
(2 and 7 days) treatment with PAA level of 3525 ppm.
TABLE-US-00006 TABLE 6 Sporicidal effect of PAA Log.sub.10
Log.sub.10 Treatment Time CFU Reduction VigorOx SP-15 1 hour 0
Total kill 2 days 0 Total kill 7 days 0 Total kill DI Water Control
1 hour 2.1 N/A 2 days 2.3 N/A 7 days 2.2 N/A
Example 5
[0042] PAA was evaluated either alone or in combination with C9CA
for fungicidal activity.
[0043] Test method: A peracetic acid stock solution containing 15%
PAA and 10% H.sub.2O.sub.2 (VigorOx SP-15) was used for methods
that specified 3500 and 20,000 ppm PAA. Capryleth-9 carboxylic acid
(C9CA) was used at concentrations of 5000 and 30,000 ppm.
[0044] Solutions were applied as a soil drench with an application
volume of 1.5 ml/cm.sup.2. The Test Medium was pasteurized
Pemberton soil. The spore inoculum was Aspergillus niger ATCC
16404. The fungicidal activity of the compositions was evaluated as
follows: Soil was pasteurized to remove background microbial
content. The soil was the filled into test cells. Aspergillus niger
ATCC 16404 was grown on Potato Dextrose Agar (PDA) plates for 5
days at 35.degree. C. A culture for test was prepared by washing a
plate with Butterfield's buffer, grinding in a sterile tissue
grinder, and filtering through a cell filter to remove hyphae and
debris. The suspension was diluted 1:100 in Butterfield's buffer
and was added to the soil as the inoculum. The inoculum was
enumerated on Petrifilm APC to determine the titer. In order to
analyze antimicrobial efficacy following the treatments, soil was
scooped from the cell and weighed into a sterile plastic cup.
Sterile deionized water was added to the cup using a serological
pipette. The cups were then capped, shaken to suspend soil, and
vortexed at maximum speed using the lab vortex. The samples were
allowed to settle for several seconds, and then 2 mL of fluid was
removed from the tube. One ml of the removed fluid was diluted in 9
mL Butterfield's buffer. The remaining removed fluid was plated
onto Petrifilm Petrifilm YM. The diluted sample was further
serially diluted and plated to 10.sup.-3 on YM. The plates were all
incubated at 35.+-.2.degree. C. for 3 to 4 days and colonies were
counted.
TABLE-US-00007 TABLE 7 Fungicidal effect of PAA and C9CA Log.sub.10
Log.sub.10 Treatment Time CFU Reduction 3500 ppm PAA 1 hour 3.2 2.4
24 hours 0.0 Total kill 7500 ppm PAA 1 hour 0.0 Total kill 24 hours
0.0 Total kill 3500 ppm PAA + 1 hour 3.6 2.0 5000 ppm C9CA 24 hours
0.0 Total kill 7500 ppm PAA + 1 hour 0.0 Total kill 5000 ppm C9CA
24 hours 0.0 Total kill 3500 ppm PAA + 1 hour 3.4 2.2 30000 ppm
C9CA 24 hours 0 Total kill Untreated 1 hour 5.6 N/A control 24
hours 5.5 N/A
[0045] As shown in Table 7, PAA alone provided a Log.sub.10
reduction of more than 2 at even at the short treatment time of one
hour. Aspergillus niger was completely eliminated after 24 hrs of
treatment. Doubling the PAA dosage to 7000 ppm resulted in complete
elimination even after only one hour of treatment.
[0046] From the foregoing, it will be appreciated by those skilled
in the art that although specific examples have been described
herein for purposes of illustration, various modifications may be
made without deviating from the spirit or scope of this disclosure.
It is therefore intended that the foregoing detailed description be
regarded as illustrative rather than limiting, and that it be
understood that it is the following claims, including all
equivalents, that are intended to particularly point out and
distinctly claim the claimed subject matter.
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