Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CHEMICAL PINCHING METHOD AND COMPOSITION
Background
Suckers in Virginia tobacco are chemically controlled by using two main
types of substances: contacts (fatty alcohols, such as n-decanol) and
systemics, such
as malefic hydrazide (MH).
Fatty alcohols are generally. very effective in killing small suckers, but
they
are characterized by a disgusting smell, which can be very annoying for
farmers
during the distribution on the cultivars, causing nausea, vomiting, suspension
of
work, etc. Furthermore people living in the surrounding areas may complain
about
the smell and limit the tobacco producer's ability to use this valuable
chemical
pinching agent in cultivation of his tobacco.
To overcome this problem new formulations have been developed containing
n-decanol and a specialized polyoxyethylene sorbitan monooleate. These new
formulations are effective at reducing odor without altering their biological
activity
and, above all, without causing any negative side-effect on the
characteristics of
flue-cured tobacco leaves, which might be detrimental for cigarette
manufacture.
Attempts have surprisingly not been successful directed to modifying the n-
decanol
formulations to contain some flavoring substances which are supposed to mask
the
smell of fatty alcohols.
Summary of the Invention
One aspect of this invention is a method of inhibiting the growth of suckers
in
tobacco plants which comprises applying to said tobacco plants after topping
an
effective amount for inhibiting tobacco sucker growth of an aqueous solution
containing as active ingredient from about 10 % to about 90 % by weight of a
saturated C~ to C~e fatty alcohol and about 90% to about 10% of
polyoxyethylene
sorbitan ester comprising a mixture of mono, di and triesters.
Another aspect of this invention is disclosed wherein said polyoxyethylene
sorbitan ester comprises a polyoxyethylene sorbitan ester having the formula
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(O CH2CH2)WOH
O
'(O CHZCH2)XOH
HO(CHzCH20)y-CH
\ O
CH2-(O CH2CH2)ZO-~ (CH2)~CH
II
CH(CH2)~ CH3
wherein w + x + y + z is between 6 and 25.
Another aspect of this invention is disclosed wherein said fatty alcohol is
N-decanol.
Another aspect of this invention is disclosed wherein said fatty alcohol is
N-octanol.
Another aspect of this invention is disclosed wherein said fatty alcohol
constituent comprises a mixture consisting essentially of N-octanol and N-
decanol.
Another aspect of this invention is disclosed wherein w + x + y + z is between
14 and 22
Another aspect of this invention is disclosed wherein w + x + y + z is between
16 and 20
Another aspect of this invention is disclosed wherein said polyoxyethylene
sorbitan ester is a condensation reaction product of ethylene oxide and
sorbitan fatty
acids wherein the fatty acids are reacted in molar excess of from 6 to 25
moles per
mole of ethylene oxide.
Another aspect of this invention is disclosed wherein said solution includes
an
emulsifying agent emulsifying agent, wetting agent, spreaders, solubilizers,
stickers.
foam suppressors and drift control agents.
Another aspect of this invention is disclosed liquid composition for
inhibiting the
growth of tobacco suckers comprising an effective amount for inhibiting
tobacco
sucker growth of an aqueous solution containing as active ingredient from
about
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% to about 90 % by weight of a saturated Ch to C, 8 fatty alcohol and about 90
% to
about 10% of polyoxyethylene sorbitan ester comprising a mixture of mono, di
and
triesters. Another aspect of this invention is disclosed wherein said
saturated fatty
alcohol comprises N-decanol. Another aspect of this invention is disclosed
wherein
5 said saturated fatty alcohol constituent comprises a mixture consisting
essentially of
N-octanol and N-decanol. Another aspect of this invention is disclosed further
including an emulsifying agent, wetting agent, spreaders, solubilizers,
stickers,
foam suppressors and drift control agents.
Another aspect of this invention is disclosed a liquid composition for
inhibiting
10 the growth of tobacco suckers as recited above further including a wetting
agent.
Another aspect of this invention is disclosed further comprising the steps of
sequentially and alternately contacting the crop buds with said aqueous
solution and
a growth regulator.
Another aspect of this invention is disclosed further comprising applying said
aqueous solution selectively to the suckering zone. Another aspect of this
invention
is disclosed further comprising applying said aqueous solution at a rate of
from
about 0.3 to about 20 ml per cultivar.
Another aspect of this invention is a method for the inhibition of secondary
growth in azaleas comprising applying topically an effective amount of the
aqueous
solution.
Another aspect of this invention is disclosed is the inhibition of plant
growth by
topical application of chemical agent to meristematic tissue, the improvement
which
comprises the utilization of an effective amount of a composition comprising
as
active ingredient from about 10 % to about 90 % by weight of a saturated C6 to
C, g
fatty alcohol and about 90% to about 10% of polyoxyethylene sorbitan ester
having
the structure
-3-
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(O CH2CH2)WOH
O
'(O CH2CH2)xOH
HO(CH2CH20)y-CH
O
CH2-(O CH2CH2)ZO-~~ (CH2)~CH
~H(CH2)~ CH3
wherein w + x + y + z is between 6 and 25.
Detailed Description of The Invention
The long chain fatty acid of this invention constitutes the active ingredient
of
the formulation for chemical suckering of tobacco but the critical factor in
masking
the objectionable odor of the fatty acid is the presence in the
polyoxyethylene
sorbitan ester of an Gas Chromatographic peak between 18.00 minutes and 19.00
minutes of column retention time. Fig 1 shows the GC trace for the
polyoxyethylene sorbitan ester of the control standard n-decanol formulation
(20/80
weight ratio). Fig 2 shows the polyoxyethylene sorbitan ester of this
invention
'10 showing clearly second peak from the left having a retention time of 18.5
minutes is
present but is not present in the polyoxyethylene sorbitan ester of the
commercial
control formulation which is Royaltac, a product of Uniroyal Chemical Company.
This surprising result in decreasing odor in the applied formulation is
believed to
derive from the particular component of the polyoxyethylene sorbitan ester
represented by this critical GC peak. In order to detect this peak any
recognized
analytic method may be utilized, but the following was used to generate the
traces of
Fig 1 and Fig 2.
Formulating Methods
A water-containing or aqueous emulsion, the most preferred embodiment of
the invention, is prepared from a solution, as described below, into which a
surface
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active agent has been added.
A suitable liquid solution is formed by dissolving the active ingredient,
saturated C~ to C~$ fatty alcohol in an aqueous or organic solvent. In most
cases, the
solvent which acts as the carrier, is an organic solvent.
Preferred solvents include aromatic hydrocarbons such as toluene and
xylene. Additional solvents that are preferred include such organic compounds
as
acetone, methanol, isopropanol, tert-butyl alcohol, cyclohexanone, dioxane,
dimethylformamide, dimethyl sulfoxide, ethylene dichloride, diacetone alcohol
and
N-methylpyrrolidone.
Surface active agents suitable for purposes of forming effective aqueous
emulsions within the contemplation of our invention are known to those skilled
in
the art.
McCutcheon's Detergents and Emulsifiers, Allured Publishing Corp.,
Ridgewood, New Jersey (1970); U.S. Patent 2,514,916, at Columns 2 to 4; and
U.S. Patent 2,547,734, at Columns 3 and 4, for example, provide detailed
examples
of such surface active agents suitable for this purpose. As is indicated in
these
references, the surface active agent may be anionic, non-ionic or cationic.
In yet another embodiment of our present invention, our composition can
take the form of an aerosol. In preparing this aerosol, we prefer to dissolve
the
compound of formula I in a first solvent.
The first solvent is conventional in the sense that it is not highly volatile.
The resulting solution is then admixed with a second solvent that is highly
volatile.
The volatile second solvent is commonly called a "liquid aerosol carrier. "
The aerosol carrier is liquid only under elevated pressure. At ambient
temperature and pressure, namely 25 degrees Celsius and one (1) atmosphere
pressure, such an aerosol carrier is typically a gas.
Other optional ingredients may also be desirable for particular applications
including: emulsifying agent, wetting agent, spreaders, solubilizers,
stickers, foam
suppressors and drift control agents at effective levels, generally between
.O1 and 2
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weight per cent.
Gas Chromatographic Test Method
The following method was utilized to determine the presence critical component
of
the which occurs at 18.5 +/- 0.5 minutes as shown in Fig 1 and Fig 2.
The samples to be tested were weighed into 3 ml reactive vials and magnetic
stirring fleas were added along with 1 ml of Silanization Reagent [BSA; TMCS;
TMSI 3:2:3 [N,O-bis(trimethylsilyl)acetamide + Trimethylchlorosilane + N-
trimethyl
silylimidazole] was added. 1 ml of toluene was added to allow the sample and
Reagent to mix and react. The samples were allowed to stir (while lightly
capped to
prevent excess air/humidity from entering and to allow pressure release) for
30-40
min. The sampled were then quantitatively transferred with HPCC grade
methylene
chloride to clean labeled l Oml volumetric flasks. The samples were then
brought to
the mark with additional methylene chloride. (U,.=l Oml) they were then
sampled for
GC analysis.
The above reaction conditions were the result of a first attempt at a much
lower concentration of sample and longer reaction time.
Chromatograph for Analysis
Varian Model 3600
Column: 15Mx0.53mm ID 1.5 ,um film DB-S+
Injector: Varian SPI on column @ 300°C, 0 min to 32~ °C
@15. °C/min hold
65 min
Oven: Initial: 60 °C, 2 min
Final 310 °C, hold 40 min
Rate 5 °C/min
Column flow Sml/min Helium make-up @ 35 mlimin Helium detector temp 320
°C.
Tobacco field trials
In these experiments, the traditional formulation of n-decanol -called
control formulation with the Fig 1 GC curve- was compared with the formulation
of
this invention having Fig 2 GC trace. Both formulations were 80/20 n-decanol
to
polyoxyethylene sorbitan ester. Two large scale field experiments were carried
out,
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one in Central Italy referred to as Region 1 {results in Table 1) and the
other in
Northern Italy referred to as Region 2 (results in Table 2).
In order to have fragrance and efficacy evaluations, some trials were carried
out on some large tobacco farms Regions 1 and 2, treating hundreds of hectares
with
the formulation of this invention and the control product without the
specialized
ingredient having the 18.5 minute GC peak of this invention.
Trial in Region 1
The trial in Region 1 was carried out on a silty-clay soil, with a pH of 7.9,
organic matter content of 1.7 % and low nitrogen content. Tobacco was grown
following the normal farm practices in central Italy, as reported in Table I.
N-
decanol for sucker control was applied as a water solution of the formulated
products (4% v/v).
The Control formulation and the formulation of this invention were
compared using a randomized block design, with four replications and a plot
surface-area of 20 m2.
Chemicals were sprayed by using a Plot Oxford Precision Sprayer, equipped
with a single-row bar, fitted with three solid cone nozzles (TG1-TG3-TG1),
delivering 600 1 ha I spray solution at 100 kPa pressure. During the
treatments,
nozzles were kept 20 cm above the plants.
Biological activity was recorded by collecting all the apical suckers in each
plot, counting and weighing them (fresh and dry weight). The average length of
the
suckers in each plot was also recorded. Tobacco leaves were harvested in three
different times 20 days apart. At each harvesting time, leaves from each plot
were
separately weighed, combined over replications and cured in different barns,
to
avoid cross contamination. Flue-cured leaves were placed in separate
polyethylene
bags for each treatment and stored for cigarette smoke flavor evaluation.
Flue-cured leaves were evaluated for quality, by a technical commission
composed of three experts from the state agency with responsibility. During
this
evaluation, the extrinsic characteristics of tobacco leaves (development,
color, tissue
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texture, consistency, etc...) were subjectively recorded and used to estimate
the
percentage of yield to be assigned to each of the three commercial grades A, B
and
C (A being the highest quality grade).
Trial in Region 2
The second trial was carried out on a sandy soil, following the normal
farming practices for Northern Italy, with respect to the choice of the
cultivar
(K326), the date of transplanting (28.5.96), plant spacing (1.10 x 0.37 m),
plot
surface area (374 m2). Biological activity was recorded.
Frasrance Evaluation
The acceptability of the smell of each formulation including the control
formulation was assessed with respect to the currently used commercial
formulation.
In all the trials, subjective evaluations were made during the distribution,
both by
the operator and by other assistants. In both trials some technicians followed
the
sprayer during the applications and recorded the smell on a scale from 0 to
100 (in
terms of intensity, acceptability, persistence and diffusion).
Results
Biological Activity
In the trial in central Italy, both formulations gave a good control of apical
suckers, with no significant differences among them.
Acceptability of the Smell
Results obtained in Region 1 are summarized in Table 1. In all the cases and
regardless of the formulation, a prolonged exposure to the smell of Control
formulation resulted in some nuisance for all the people involved in the
experiments.
The flavor of the formulation of this invention proved to be characterized by
a high
intensity at the treatment and two hours later, but it was considered, due to
its
"neutral" smell, more acceptable than the commercial one.
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TABLE 1
Formulation At 2 hours 8 hours 24 hours
the later later later
treatment
A I I I I
~I Ex. 1-invention50 80 60 20 20
Control formulation0 100 70 40 20
Footnotes to Table:
I=intensity of smell. The I scale=0-100 with [0=zero intensity 10=high
intensity.
A=acceptability of smell. The A scale=0-100 with [0=unpleasant 10=acceptable.
* Number of replication of readings that support these averages is 5 persons
The Example 1-the formulation of the invention, was considered to be much
more acceptable than the commercial formulation for its smell and low
intensity and
persistence.
TABLE 2
Formulation Smell 6 haurs 24 hours
at later later
the
treatment
A I I I
Ex.l-invention 60 20 () 0
Control formulation0 100 0 0
Footnotes to Table:
I=intensity of smell. The scale=0-100 with [0=zero intensity 10=high
intensity.
A=acceptability of smell. The scale=0-100 with [0=unpleasant 10=acceptable.
* Number of replication of readings that support these averages is 5 persons
All the trials in these two years showed that the new formulations of this
invention's formulation are as effective as the currently used one in
controlling
suckers in tobacco. Furthermore the abovementioned formulations did not
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negatmely influence the qualltatme and quantitative characteristics of flue-
cured
tobacco .
Concerning the smell of fatty-alcohols, the formulation of this invention
proved to be more acceptable than the standard formulations. Example l, the
formulation of the invention, proved to have a less intense smell compared to
the
Control formulation and thus was more acceptable for the operators working on
the
two experimental farms, for the farmers of the tobacco farms and for people
living
in the surrounding area. Because of its "neutral" smell, this formulation was
considered the best one to solve the problem of the unpleasant smell of fatty
alcohols
both Regions 1 and 2, the biggest producers (90%) of Virginia tobacco in
Italy.
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