Note: Descriptions are shown in the official language in which they were submitted.
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TREATMENT OF PLANTS WITH SALICYLIC ACID
AND ORGANIC AMINES
Background of the Invention
1. Field of the Invention
The present invention generally relates to methods for improving disease
resistance in plants without adversely affecting the plant growth. More
specifically, the present invention is directed to methods for achieving such
results by treating the plant tissue with an ortho- substituted benzoic acid
and an
organic amine.
II. Description of the Background
Agricultural pesticides are used to control unwanted fungal, viral, and
bacterial populations. These compounds have allowed the producer to manage
disease pressure. Although, these traditional chemical applications have been
valuable in the past it is unlikely that the producer will be able to use them
at the
same rate into the future. I'herefore, improved methods for controlling
disease
by stimulating the plant's natural processes are desirable.
For some years it has been known that plants have the ability to produce
pathogenese proteins. Once these proteins are expressed plants may have the
capacity to protectthemselves from pathogenic insults. The efforts of
individuals,
chemical producers, and academic institutions are now concentrated on
producing genetically manipulated species that either repress or express these
enzymes or their perceived precursors. Innumerable compounds have been
documented as inducers of the pathogenese proteins. However, because the
compounds applied separately induce a given set or class of enzymes they have
not been found to be efficacious in preventing infection in field hosts.
An inoculation with an array of elicitors would induce the expression of
recessive enzymes of two or more classes. These enzymes would enable the
treated plant to defend itself against pathogens.
Plants are continually under attack from pathogenic microorganisms. The
pathogenic insults from the exposure to fungal, viral, and bacterial assaults
are
frequently confined to the area of attack. These insults often cause lesions
as
the cell dies. The cell death is part of a hypersensitive reaction (HR) to the
pathogen. This reaction acts as an inoculant for the lesion forming pathogen,
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and also, as an inoculant for unrelated pathogens. This inoculation provides a
systemic acquired resistance (SAR). It is now well established that some
phenolic compounds can induce these pathogenese related proteins in the
absence of the pathogenic organisms. These compounds include cinnamic,
benzoic, coumaric, and salicylic acids and salts. It has been found that
exposing
a plant to such phenolic compounds prior to the attack of the pathogen can
minimize the effects. The pathogenese proteins are chitinese enzymes. Three
classes of chitinase have been identified as follows:
= Class I - catalytic activity, cystine rich (protein spacer
between amino and carboxyl ends) - ethylene
induced.
= Class II - catalytic activity (all are part of the protein
spacer) - SAR induced.
= Class III - catalyst activity - SAR induced.
It is assumed the expression of all three classes of Chitinases
simultaneously would provide greater protection then the expression of only a
single protein. Ethylene, a naturally occurring plant hormone, often used to
induce certain events iri the plant life cycle, has been shown to induce
expression of pathogenese proteins. Chitinase has been found in ethylene
treated leaves. It has been suggested that these basic enzymes serve to
protect
plants against potential pathogens. Ethylene, a gas, is expressed throughout
the
plant kingdom in response to drought, flooding, frost, and physical injury.
The
plant hormone has aiso been reported to be expressed with chemical
applications. Auxins have been shown to induce expression of ethylene at very
low concentrations when applied. They are aiso useful for the inducement of
chitinase. Auxins have also been shown to induce a class of pathogenese
proteins. Sugars have also been shown to induce ethylene biosynthesis.
Two classes of Chitinases have been identified that are associated with
the onset of systemic acquired resistance. While transition metals are needed
for nutritional purposes, foiiar application of manganese has been shown to
induce a class of pathogen related (PR) proteins. Zinc, as a nutrient supplied
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above optimal levels, has been shown to suppress Spongosspora subterranea
in watercress. High zinc levels effectively suppress watercress chloratic leaf
spot
virus through control of its vector, the fungus.
Systemic resistance is typically characterized by a reduction in lesion size.
The lesion response is a programmed cell death to isolate the pathogen and
prevent further infection. Wtien the pathogenese related proteins are
expressed
prior to disease inoculation the pathogens can be isolated within the lesion
in a
shorter time period. It has been postulated that those substances that induce
pathogenese related proteins would prime the plant for disease resistance, if
applied prior to the insults.
Although, many corripounds have been shown to induce pathogenese
related proteins the infection resistance is not the same for all cultivars or
pathogens. However, the lesion size for a given infection can be inverseiy
correlated with the dose of the inducing chemicai administered and, if
application
of a given set of inducers at a concentration great enough to induce
production
of an array of pathenogese related proteins, then the pathogen insult could be
minimized to the extent that no signs of infection would be visible. That is
to say,
there would be no visible lesion formation.
So then, the application of several compounds known for inducing or
eliciting the production of different classes of pathenogese related enzymes
simultaneously provides greater protection against infection, prevents or
minimizes the rate of infection and, if administered after infection, halts
the
infection.
Many compounds have been documented to induce the production of
ethylene in plants. Auxins, a class of plant hormones, have been shown to
promote the production of the gas in plants at low concentrations, i.e.,
Auxins
may be used to elicit pathogenese related proteins for plant defense. Because
Auxins have been well studied and auxin structure activity relationships have
been identified, synthetic compounds with auxin like biological
characteristics are
readily contrived. Naturally occurring Auxins typically have an indole core
structure. The indole beconies biologically active with either auxin or anti-
auxin
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like activity with molecule functionafity substitution. With the use of
resonance
structures the structural similarities are easily seen. Therefore, the use of
benzothiadiazoles and their derivatives as biologically active materials may
be
actually mimicking Auxins. The relationship between ethylene and Auxins has
been well documented. The promotion of pathogenese related proteins from
exposure to ethylene is also well documented, e.g., the use of Auxins and
other
ethylene elicitors for the purpose of inducing an array of pathogenese related
proteins is now documented.
Ethylene is also documented to be expressed from injury to a plant. If one
were to compare pathogeriese related protein production from known elicitor
applications then the difference in those proteins induced would be from
either
concentration applied, corripound applied, or compounds application method.
Because the amount of pathogenese related enzymes expressed is roughly
proportional to the amourit of inducer applied and because lesion size is
proportional to the amount of pathogenese related protein produced, the amount
of an inducement elicitor applied should maximize the promotional properties
of
the inducement elicitor without causing harm. For salicylic acid an optimum
concentration would be greater than 75mM.
Substituted phenyl compounds are usually defined as aromatic
substances that possess one or more functional groups. Such compounds are
essential for the regulation of plant growth and development. Phenolics are
plant
growth inhibitors. Natural growth inhibitors (phenolics) are found in growing
and
dormant plants, fruits and seeds. These compounds are thought to work in
concert with the phytohonmones to regulate the growth and development of
organisms throughout their life cycle.
Some of the regulatory functions of these compounds include: signal
producers for interactions with other organisms, growth regulation and
structural
integrity of each cell in the organism. Salicylic acid application has also
been
found to inhibit ethylene biosynthesis, inhibit germination, block wound
responses, interfere with membrane ion transport and absorption of roots,
induce
rapid membrane depolarization and collapse of the transmembrane
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electrochemical potential, reduce transpiration in leaves and epidermal
strips,
reverse ABA induced stomatal closure, affect leaf abscission, and affect
growth
inhibition. These responses will almost certainly cause a decrease in the
potential yield of a crop.
United States Patent No. 5,654,414 to Ryals, et al, states ". .. in order to
achieve a desirable phenotype the chimeric gene may need to be expressed at
levels of 1% of the total protein or higher. This may be the case for fungal
resistance due to increased proteinase inhibitor expression. In cases where
the
energy expended to produce high levels of foreign protein may result in a
detriment to the plant whereas, expression of the gene only when desired, for
instance when a fungal or irisect infestation is imminent, would result in
reduced
drain on energy, and therefor yield.
However, because salicylic acid has a Ka of 1.05 x 10-3 it would not
generally exist as a protonated acid in the xylem, phloem or cytoplasm; a
conjugate base or ester would probably exist in such an environment. The use
of weak bases, specifically amines, for the neutralization of the weak acid
would
mimic the naturally occurring compounds as found in nature. High
concentrations of phenolics have been found in the presence of amines during
flowering.
Substituted phenyl compounds have long been known to inhibit the
growth in plants. Nonetheless, some phenolic acids are known to induce the
production of proteins that provide the SAR. The SAR acts as an immunity
response that protects the plant against fungus, bacteria, and virus. This
response is generally triggered from interactions between the plant and
pathogen, i.e., viral, fungal, and bacterial agents. The immune response is a
systemic gene expressiori that requires phenolic accumulation. The SAR
generally lasts weeks to months.
Because many pathogens attack the leaf surface of a plant, and, that the
first barrier to the pathogen is typically the cuticle, and that cuticle
consists of
fatty acid esters; the cuticle is soluble in alcohol or ketone. The use of
hydroxyl,
carbonyl, or ketal functional groups in combination with the chelated metal
ions
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may aid in the cation permeability through the cuticle to the plant cell. It
has been
found that the use of copper salts, either applied to the leaf or soil, when
present
in the cell at 10 to 100 times the amount necessary for normal growth and
development, may control pathogens. Because of the efficacy of chelated
copper the amount of copper salt necessary at an application to the soil or
the
plant itself to raise the copper content in tissue analysis is lowered. In
copper
deficient soils two kilogram/hectare of chelated copper when foliar applied
has
been shown to add enough copper ion into the plant tissue. An newfound
method of foliar applicatiori of chelated copper at a concentration of 0.006M
(equivalentto 0.25-0.5 kilogram/hectare) has been shown to raise the dry
weight
tissue analysis to levels of at ieast 10 to 60 times the amount necessary for
normal growth and development; this new method is at least 2 to 10 times more
effective then synthetic compounds from a foliar application. That is to say,
if
synthetic chelates were neuturalized with the organic amine that the same
efficiency might be found. It may be the osmotic potential of inorganic salts
that
sets up a directional gradient opposite of the intended effect that minimizes
the
actual absorption of the cation. So then, the use of the organic
polyfunctional
amines with the synthetic chelates may increase their efficacy.
Because plants are typicaily under disease pressure from a number of
pathogens, and, the enzyrnes expressed from a given elicitor are somewhat
pathogen specific, the application of a several elicitors offers greater
protection.
If the elicitors were then delivered with a melanin synthesis inhibitor then
protection would be universal against fungi. So application of several
compounds known for inducing or eliciting the production of different classes
of
pathogenese related enzymes simultaneously should provide greater protection
against infection, prevent or minimize the rate of infection, and if
administered
after infection, halt infection.
Accordingly, those skilled in the art had sought methods for obtaining the
perceived benefits of disease inhibition by treatment with salicylic acid
without
causing resultant plant growth inhibition. Thus, there has been a long felt
but
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unfulfilled need for methods for achieving that end. The present invention
solves
that need.
Summary of the Invention
The present invention is directed to processes for improving pant
resistance to disease without inhibiting plant growth. These processes are
broadly directed at treating the plant with an ortho-substituted benzoic acid
and
nitrogen-containing compounds that is selected from the group consisting of
the
organic amines and compounds which will metabolize to an organic amine.
These processes have been found to be further improved by simultaneously
treating the plant with a chelated micronutrient metal. Finally, even more
improvement has been observed where the plant is further treated with an
ethylene inducing compound. Alternatively, it has been found that the benzoic
acid and derivatives and nitrogen-containing compounds may be applied as an
amine salts of the substituted benzoic acid. The acid, nitrogen containing
compound, and optionally, chelated micronutrient metal and ethylene-inducing
compounding, should be applied to the foliage of the plant as a solution
flocked
with a suitable carrier medium.
The nitrogen-containing compound is selected from the group consisting
of the polyamines, tertiary amines, propylamines, and organic compounds which
will metabolize to produce a propylamine. Preferred compounds are the organic
amines having the structure
R, - N~R3
where R,, R2 and R3 are the same or different and are selected from the group
consisting of hydrogen and alkyls and substituted alkyls having not more than
three carbon atoms, provided that R,, R2 and R3 are not all hydrogen. Most
preferred are monoethanolamine, propylamines and dimethyiaminopropylamine
(DMAPA).
The preferred ortho-substituted benzoic acid is salicylic acid. The
chelated micronutrient metal preferably is selected from the group consisting
of
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the alkaline earth metals, the transition metals and boron. The ethylene-
inducing compound of choice is indole-3-butyric acid.
The method of the present invention has been found to increase the
resistance to disease exhibited by a variety of crop plants. Most
significantly,
this increased resistance was achieved without the deleterious effects which
condemned prior attempts to employ salicylic acid to prevent or minimize
disease in plants. This result has been achieved by simultaneous application
of
a nitrogen-containing compound, most preferably a tertiary amine or
propylamine
in accord with the present invention. Accordingly, the methods of the present
invention have solved the problems which previously plagued attempts to
capitalize on the benefits associated with the use of salicylic acid.
Thus, the long felt, but unfulfilled need for improved methods for
enhancing plant disease resistance without inhibiting plant growth have been
met. These and other meritorious features and advantages of the present
invention will be more fully appreciated for the following description and
claims.
Detailed Description of the Preferred Embodiments
The present invention provides processes for improving plant resistance
to disease without inhibiting plant growth. The processes of the present
invention overcome the problems which plagued prior attempts to employ
salicylic acid and related acids and salts. For example, while it has been
known
that treatment of plants with salicylic acid can inhibit disease, the
treatments,
unfortunately, have also resulted in a significant stunting, and even death,
of the
plants. It has been impossible to previously take advantage of the beneficial
results of salicylic acid treatment. Surprisingly, Applicant has discovered
that
when treatment with the acid is combined with a nitrogen-containing compound,
preferably selected amines, the deleterious effects have been overcome and
plant resistance to disease have been improved without any adverse effect on
g rowth .
The present invention is broadly directed to a process for improving plant
resistance to disease without inhibiting plant growth. In its broadest aspect,
the
present invention is directed to the treatment of plants with an ortho-
substituted
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benzoic acid and a nitrogen-containing compound selected from the group
consisting of the organic amines and compounds which will metabolize to an
organic amine. The most preferred ortho-substituted benzoic acid is salicylic
acid. The preferred nitrogen-containing compounds are selected from the group
consisting of the polyamines, tertiary amines, propylamines and organic
compounds which will metabolize to provide a propylamine. A particularly
preferred group of amines are those having the structure
R - N/~R3
where R,, R2 and R3 are the same or different and are selected from the group
consisting of hydrogen anci alkyls and substituted alkyls having not more than
three carbon atoms, provided that R,, R2 and R3 are not all hydrogen.
Particularly preferred are rnonoethanolamine, propylamines and DMAPA and
mixtures thereof. Alternatively, it has been found that the acid and amine may
be applied as the amine salt of the acid. Most preferred are the amine salts
of
salicylic acids.
Further methods have been achieved by including with the treatment a
chelated micronutrient metal. Preferably these metals are selected from the
group consisting of the alkaline earth metals, the transition metals and
boron.
Exemplary cations include copper, zinc and mangenese.
Finally, it has been found that inclusion of an ethylene-inducing compound
in the treatment may be beneficial. An example of such an ethylene-inducing
compound is indole-3-butyric acid.
The ortho-substituted benzoic acid and nitrogen-containing compound,
together with the optional chelated micronutrient metal and ethylene-inducing
compound, should be applied to the foliage of the plant. Preferred treatment
includes foliar application of the solution of those compounds in a suitable
carrier
medium. While the most preferred carrier medium is water, fertilizer solutions
and any agriculturally acceptable medium may be employed. The ortho-
substituted benzoic acid should be present in the treating solution in a
concentration of not more than about 0.1 M, preferably in the range of about
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0.0001M to about 0.01 M. However, the nitrogen-containing compound may be
present in significantly higher percentage, up to about 25 percent-by-weight.
In order to facilitate a further understanding of the invention, the following
examples primarily illustrate certain more specific details thereof.
Example 1
A solution of chelated metal ions, neutralized with sodium hydroxide,
consisting of 1.5 x 10-2 M Cu (II), 1.5 x 10' M Zn (II), 1.8 x 10-2 M Mn (II),
and a
3.8 x 10-3 M sodium salt of salicylic acid was appiied to snap dragons. The
plants were severely damaged by the application and death of some plants
followed. While at the same time a solution of chelated metal ions,
neutralized
with polyfunctionalamines, consisting of 1.5 x 10-2 M Cu (II), 1.5 x 10-2 M Zn
(II),
1.8 x 10-2 M Mn (II), and 3.8 x 10-3 M amine of salicylic acid was applied to
snapdragons without any visible damage occurring.
Example 2
Gerber Daisy infected with powdery mildew was treated with a solution in
accord with the present invention in a university study. A concentrated
solution
containing 10 grams/liter salicylic acid, 20 grams/liter DMAPA and two percent
each of copper (li), zinc (II) and mangenese (II) was prepared. The metals
were
provided in a form of the oxides chelated with citric acid and
monoethanolamine.
This concentrated solution was diluted 50 to 1 with water. The concentration
of
components in the following solution was about 0.0015M amine salt of salicylic
acid, 0.006M each copper (Il) and zinc(II) and 0.007M mangenese (II).
Commercial available Auxiri (indole-3-butyric acid) was added as an ethylene-
inducing compound. The solution so prepared, together with a control of water,
was applied to Gerber Daisy infected with powdery mildew. A single foliar
application was found to prevent infection. Subsequent applications of the
same
solutions applied at two week intervals continued to prevent infection. All
plants
treated with salicylic acid/amine solution were found to be free of visible
lesions
at the end of the study. The control plants, treated only with foliar applied
water,
all died.
Example 3
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In a field test covering approximately 700 acres of watermelon infected
with anthracnois was treated with a solution in accord with the present
invention
together with control. A concentrated solution was prepared in accord with the
description in Example 2. A final solution for application was prepared 19 to
1
dilution with water. The concentration of components in the final solution is
about 0.0038M amine salt of salicylic acid, 0.015M each copper (II) and zinc
(II)
and .018M mangenese (II). Again, Auxin was added as an ethylene-inducing
compound. A single treatment with the foregoing solution prevented further
infection by anthracnois. After two weeks, a second treatment with an
identical
solution was applied. All plants treated were free of further visible signs of
disease. The controlled portion of the field, being treated only with foliar
applied
water, had no harvest. In fact, substantially all of the untreated plants
died.
Example 4
Celery was successfully treated in accord with the present invention by a
similar solution. A final solution containing salicylic acid, an amine,
chelated
micronutrient metals and an ethylene-inducing compound was prepared in
accord with that described in Example 3. That solution was foliar applied to
celery in a Florida field. Three applications were made during the growing
season. While no disease was present, an increase in biomass and size was
recorded at harvest. Control plants were treated with water. Using a sample of
thirty treated and thirty controlled, biomass and size were recorded at
harvest.
Harvest mass of the controlled plants averaged 1.04kg per plant while those
treated with the salicylic acid/amine solution averaged 1.32kg per plant.
Height
of the plants was also increased from an average of 61cm to 64cm. Thus,
treatment in accord with the present invention, far from stunting or
inhibiting plant
growth, resulted in a 5 percent increase size, together with a 27 percent
increase
in biomass.
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Example 5
A series of test were performed by an independent laboratory to test
salicylic acid/amine solutions against industry standards. The molar
concentrations of compone!nts in solutions were as follows:
Coppe Zinc Mangenese Salicylic Acid Auxin
r
Solution 1 0.012 0.012 0.015 0.003 1.5 x 10-5
Solution 2 0.0062 0.0061 0.0073 0.0015 7.5 x 10-6
Solution 3 0.0031 0.003 0.0036 0.00075 3.8 x 10-,
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The solutions described above were applied both prior to (protective) and
after
(curative) inoculation with pathogens. The results are shown in the following
table:
Treatment Rate P. infestas P. oryzae P. recondita
(late blight on (rice blast on (wheat rust on
tomatoes) rice) wheat)
Protective
Solution 1 100.0 90.0 80.0
Solution 2 100.0 80.0 50.0
Solution 3 100.0 0.0 0.0
(ppm)
Metalaxyl 30 92.7 - -
Metalaxyl 10 60.0 - -
Benomyl 100 - 100.0 -
Benomyl 40 - 40.0 -
Propiconazole 5 - - 100.0
Propiconazole 1 - 36.7
Curative
Solution 1 80.0 43.0 0.0
Solution 2 65.0 0.0 0.0
Solution 3 36.7 0.0 0.0
(Ppm)
Metalaxyl 30 81.7 - -
Metalaxyl 10 48.3 - -
Benomyl 100 - 100.0
Benomyl 40 - 35.0 -
Propiconazole 5 - - 97.7
Propiconazole 1 - 43.3
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Example 6
Corn was treated with a solution in accord with that prepared in Example
3 except that a 50:1 dilution with water was used. While disease was not
present during the growing period, an increase in grain mass was recorded at
harvest. Average yield per acre at harvest for controls (treated with water)
was
about 181.9 bushels per acre; average for the portion of the field treated in
accord with the present invention was about 192.5 bushels per acre. In both
cases nitrogen was applied at a rate of 100 pounds per acre.
Example 7
Red Oak Lettuce was successfully treated in accord with the present
invention in an experimetit conducted at the University of Queensland in
Australia. A single spray at early seedling stage soon after planting
prevented
disease. Further, significant increases both diameter and height were
observed.
A treatment solution in accord with that described in Example 3 above was
prepared and foliar applied to the plants at early seedling stage. Ten plants
were treated with that solution while an additional ten plants were maintained
as
a control treated with water. Average plant diameter increased from 25.2cm to
27.7cm, an increase of about 10 percent. Similarly, average plant height
increased from 14.8 to 16.7cm, an increase of about 13 percent. Thus, not only
did treatment of growth in the present invention prevent disease, but
surprisingly
produced significant increase in yield.
Example 8
In another experiment using Red Oak Lettuce, yield was shown to be
significantly improved. The application was designed and conducted in accord
with that described in foregoing Example 7. Again, 10 plants were treated with
a solution in accord with the present invention while 10 were maintained as
controls treated with water. Tops and roots were collected, cleaned and
weighed at harvest. Average top weight increased from 186.40gm to 226.67gm,
an increase of 22 percent. Average root weight increased even more
dramatically, from 59.80gm to 78.89gm, an increase of about 32 percent.
Finally, total weight increase from 246.20gm to 305.56gm, an increase of 24
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percent. Thus, not only did treatment in the present invention prevent
disease,
but surprisingly produced significant increase in yield.
Example 9
Another test using Green Oak lettuce was set up to measure disease and
plant diameter. A single application of the solution described in Example 7
was
made at the early seedling stage soon after transplanting. Fifteen plants were
treated with that solution while fifteen more were maintained as controls
treated
with water. Diameter was determined by measuring the extremities of the outer
leaves. Disease ratings was made by removing a plant from its whole and
examining the roots. Ratings were graded on a visual scale from 1 to 5; of the
roots graded 1 with no sign of infection while root showing severe pythium
damage were rated 5. Treatment in accord with the present invention increased
average plant diameter frorn 18.93cm to 23.07cm, an increase of 22 percent.
An even more dramatic improvement was seen with respect to disease rating.
The control averaged a 3.38 disease rating while that plants treated in accord
with the present invention vvere dramatically decreased to an average of 2.00.
Thus, a spectacular 59 percent improvement in disease rating was achieved with
one foliar application.
Example 10
The example demonstrates the effect of salicylic acid in growth inhibition
when used with other amines. The work was conducted at Texas A&M Crop
Biotechnology Center, College Station, Texas.
Each seed was planted, five seeds per pot, and thinned to two per pot
after germination. No fertilizer was employed. Foliar applications were made
when the plants were 18 days old. The tops of the plants were then harvested
two weeks later and dried in an oven. The following four blends were used for
the foliar applications:
Blend I Grams
Water 460
DMAPA 5
Salicylic Acid 5
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Blend 2 Grams
Water 500
MEA 200
Citric Acid 200
Salicylic Acid 8
DMAPA 17
Formic Acid 10
Blend 3 Grams
Water 460
Salicylic Acid 5
DMAMP (80%) 4
Blend 4
Water Control
It was observed that the dry weighi: was not decreased by the use of a
salicylic acid, the
presence of the amine prevented growth inhibition. Indeed, it was noted that
when
using Blend 1 there was a slight increase in dry weight over that achieved
with the
control as by using blends 2 and 3 dry weight decreased insignificantly.
EXimple 11
The procedure of Example 6 was followed with the exception that no nitrogen
was applied. The test plants were soybeans. It was found that the average unit
per
acre at harvest for the control (treated with water) was 44.6 bushels per acre
while the
average field per acre for plants treated with the solution used in Example 6
was 49.4
bbihels per acre. It is to be noted that in both cases of Example 6 and in
this Example,
the solution was applied as a 2% solution.
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The foregoing description of the invention has been directed in primary to a
particular preferred embodiment in accord with the requirements of the Patent
Statutes
and for purposes of explanation and illustration. It will be apparent,
however, to those
skilled in the art that many modifications and changes in the specifically
described
mgthods may be made without departing from the true scope and spirit of the
invention.
For example, while salicylic acid and an amine are preferred, other organic
acids and
amines may be used. Further, the amine salts of salicylic acid may be
employed. Also,
while it is preferred to dilute the acid/amine salts in aqueous solutions, it
may also be
delivered in other agriculturally acceptable carriers. Further, while
Applicant has
athmpted to explain the reasons for the unexpectedly improved results
achieved,
Applicant does not wish to be held to the theory proposed because that
mechanism is
not fully understood. Therefore, the invention is not restricted to the
preferred
embodiment described and illustrated but covers all modifications, which may
fall within
the scope of the following claims.
