Note: Descriptions are shown in the official language in which they were submitted.
CA 02200188 2006-07-26
USE OF NEEDLELESS PNEUMATICALLY ACTUATED INJECTION
APPARATUS FOR ADMINISTERING ACTIVE SUBSTANCE TO PLANTS
SPECIFICATION
The present invention relates to the use of pressure-actuated in-
jection devices without a needle for the administration of active
substances to plants.
The injection as a form of administering active substances to
plants has been known for long. It is superior to the usual applica-
tion methods, such as spattering and spraying, because there is
no spray drift and environmental pollution.
In the meantime a iot of injection devices have been developed to
optimize the injection methods in plants, in particular in plants
having lignified trunks. The so-called "Mauget-System" is to be
mentioned first as one of the widely used injection systems; it is
described, for example, in the patents US 3 304 655 and US 4
365 440. Although the construction of the devices described in
these patents differ in details, both operate according to the same
principle. They relate to a nonrefillable injector for the single dos-
age (disposable injector) consisting of a container filled with the
liquid to be injected and a feed pipe to be inserted into the trunk.
The container is composed of two bowls which are telescoped by
means of a groove and tongue system. When the two components
are pressed together, the pressure of the gas phase above the liq-
uid is increased. The medium to be injected is then pressed
through the feed pipe into the trunk of the plant. However, the
use of these injection devices in horticulture has already shown
deficiencies: the liquid injection by means of these systems always
involves the risk of an active substance loss (liquid leakage from
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the bore aperture in the trunk) on the one hand, and this injection
method is time-consuming and requires heavy application techno-
logical expenditure on the other hand.
A useful alternative is the high-pressure injector developed in the
USA in the seventies. An example relating to this injection device
is the patent US 4 011 685. The main advantage of this device is
the minimized risk of liquid leakage obtained by installing a pump-
ing device and a so-called self-closing needle. When this injection
device is used, lignin fibers of the tissue cells near the needle rap-
idly contract because of the high pressure used (up. to 350 bar) v .: ..-
and therefore the previously formed cavity is sealed up; preventing
possible emergence of active substance: Thiswinjection:system is.:,.
suitable for repeated application to inject liquids of various vis-
cosities. However, the disadvantage lies in the fact that an ac-
commodation space must generally be pre-drilled into the plant
trunk when this system is used. Moreover, it is possible that the
sealing degree of the opening depends on the lignification extent
of the cell walls and therefore on the kind of plant concerned. This
means that an injection by means of this device finally involves a
potential risk of liquid leakage.
U.S.-patent 4 078 087 discloses an injection system as another
injection technique. Here the main concern is that the plant trunk
is uniformly supplied with the injection medium. In this case it is
decisive that the liquid is not injected into one single cannula but
into a delivery system. The delivery system, into which the injec-
tion medium is forced under pressure out of a container, consists
of a coupling, a varying number of so-called 'T'-connectors which
are inserted into pre-drilled openings in the trunk, and a closing
valve. The 'T'-connectors which represent flow switches wherein
part of the liquid is injected into the trunk and the remaining por-
tion is passed on ensure that the conductive system of the plant is
evenly supplied with active substance fluid on all sides.
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Like in the injection devices described in the present document so
far, this system also involves the problem of undesired emergence
of injected medium.
The injection system described in U.S.-patent 3 576 276 is men-
tioned as another injection system known from the art. The injec-
tion device described therein uses the well-proven operating prin-
ciple of a subcutaneous syringe. The new thing is the use of an
application aid in the form of a pipe inserted into the tree trunk at
the desired depth prior to injection. This additional feed pipe, in
which the injection needle is located during application, permits
refilling of the needle with the medium to be injected prior to ap-
plying the injection cylinder with the displacement piston. This
modification of the usual sequence of working steps during appli-
cation is used to inject the liquid in a fast and effective manner,
caused by freedom from air bubbles.
However, the disadvantage of this process lies in the relatively
heavy investment in time and work caused by using the additional
application aid.
Among the other injection processes described in the art, that
disclosed in CA-PS 1 089 645 is to be mentioned, this operates by
using an injection device.-The subject matter of this invention is a
pressure-injector for use in plants, particularly developed for con-
trolling mycetogenic vascular diseases (e.g. elm death) in trees.
This device has primarily been developed to permit injections
without active substance losses. The minimization of liquid leak-
age required for this purpose is obtained by using a feed pipe
(feed needle) whose surface is serrated or toothed. This uneven
surface structure forms a close contact to the adjacent plant
tissue; for this reason the medium already injected cannot flow
back, or it flows back to a minor degree.
CA 02200188 2005-10-13
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Finally, the injection device described in U.S. 4 164 093 is a mini
pressure-injector for the use in small-diameter plant sprouts, for
example in seedlings, tree branches, or young plants. The device
comprises a syringe (according to the construction of a commer-
cial subcutaneous syringe with single-use needle) and a commonly
used multipurpose gardening tongs, the syringe being rigidly fas-
tened at the stationary jaw. The free adjustability of the jaw width
permits the mini-injector to be positioned at optional sites at the
shoot axis and ensures flexible handling of the total device in de-
pendence on the kind of plant used.
None of the injection devices known from the art for the use in
plants succeeded in solving the problem of leakage of the injected
medium in a perfect and satisfactory way. Moreover, most of the
above-mentioned injection systems require a relatively heavy in-
vestment with respect to equipment and time. In addition, these
devices are only suitable for injecting liquid media.
Since none of the publications mentioned so far, gives an indica-
tion as to using injection devices in plants which are not lignified,
one may assume that they are not suitable for such an application.
It is the object of the present invention to provide an injection
method with which both solid and liquid media are injected, in the
last-mentioned case avoiding the disadvantage of leakage, and
which can be used both in woody plants and in plants having
unlignified shoot axes.
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The present invention will be described in greater detail in the fol-
lowing description.
Pressure-actuated injection devices without a needle have been
known in human and veterinary medicine for some time. For sev-
eral years now, they have been used for diagnostic and therapeu-
tic purposes where painless injection or puncture is required. They
are commercially available under various names (for example, the
vaccination syringe manufactured in the former Soviet Union
"Bienchen", "Jet" developed in the USA, and the Hungarian vac-
cination device "Viper") and are described at great length in sev-
eral patent documents and published patent applications (e.g., DE
34 67 301, EP 0 1 19 286, US 4 966 581, DE 31 15 373). Up to
the present, they have not been used in plants.
Most surprisingly, it has been found that needle-free injection de-
v i c a s h a v i n g t h a b a s i c or general construction as described in
the above pat-
ent documents are excellently suitable for injecting various sub-
stances into plants.
The injection devices of the mentioned kind are devices wherein
the medium to be injected leaves the jet chamber of the device
through a nozzle under such an energy that an injection without
needle is possible. On the object (plant organ) to be injected the
generated short pressure burst forms the injection opening with
desired depth required for the injection medium. The injection
depth can be varied by the angle and the distance of the device to
the object to be injected: for example, the closer the nozzle to the
object surface, the deeper the injection cone.
The pressure required for shooting out the medium to be injected
can be generated in various manners depending on the construc-
tion of the injection device. To this end, gas issuing from a sparket
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bulb (DE 34 67 301 ) or a pressure pump (DE 31 15 373) can be
used as pressure generating means.
The particular advantage of the present invention lies in the fact
that the risk of an active substance loss caused by leakage is
completely eliminated by using this type of cannula- and needle-
free injectors. This particularly applies to injections into unlignified
plants wherein the injection opening closes very fast because of
the osmotic pressure of the neighboring cells.
The further advantages achieved by the present invention lie in the
fact that the medium to be injected may be present in a flowable,
semisolid, or solid form. With this type of jet-nozzle-injection it is
possible to inject also highly viscous liquids into the objects by
using an appropriately high pressure. The reason is that cannulae
and needles are not used in this case. Thereby the problem of
needle occlusion, e.g., by clogging, usually occurring in case of
viscous media is excluded.
The needle-free injection process also offers the possibility of in-
jecting media in crystalline form. In this case individual particles of
the injection agent must have a sufficiently small (microfine) di-
mension. The preferred particle size is the range of < 1 Nm.
In this connection, the active substances may be present either
alone or in admixture with one another. They may be dissolved or
dispersed in the injection medium.
Active substances which can be administered to plants by means
of injection devices without a needle primarily include systemically
active plant protection agents (insecticides, acaricides, fungicides,
bactericides), as well as plant restoratives and growth regulators.
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Systemic insecticides include, for example, butocaroxim, di-
methoate, fenoxycarb, methamyl, oxamyl, oxydemeton-methyl,
pirimicarb, or propoxur.
Systemic acaricides include, for example, clofentizine, fenbutatin
oxide, and hexythiazox.
Systemic fungicides include, for example, benomyl, bromucona-
zole, bitertanole, etaconazole, flusilazol, furalaxyl, fosetyl-AI,
imazalil, metalaxyl, penconazole, propiconazole, thiabendazol,
triadimefon, triadimenol, or triforine.
Flumequine, for example, is to be mentioned among the systemic
bactericides.
Plant restoratives include, for example, plant extracts from nettle,
tansy, horsetail, or herbaceous knotweed. These bioactive sub-
stances may develop a local or a systemic action in the plant, de-
pending on the site of injection.
Systemic growth regulators include, for example, ethephon and (3-
indolylacetic acid (IAA).
w In this connection, a preferred application of the needle-free injec-
tons is the administration of growth-inhibiting substances which is
an alternative to manual corrective and cutting measures in public
gardens. During the last few years,. injection systems have gained
increasing importance in this field (in particular in the USA).
Further substances which can be processed by using injection de-
vices without needles are wood preservatives and wood impreg-
nation agents.
For centuries, lumber has been impregnated with oil and wax
mixtures or other chemicals (e.g. against xylophagous insects) or
provided with film-forming covers as a protection against aging
and weather factors.
However, these treatments have the disadvantage that they must
be renewed from time to time.
The use of needle-free high-pressure injectors offers a favorable
alternative to the conventional impregnation method.
Owing to the fact that relatively high-viscous media can be in-
jected by means of this device, it is also possible to inject poly-
mer-containing liquids into a piece of wood to be treated by using
said devices.
This is of particular importance since the injection medium maybe
a formulation having a~controlled active.substance release. Since it
is possible with this type of active substance preparations to de-
termine the release profile (duration and rate of release), the nee-
dle-free injection process offers the advantage of providing a long-
term protection of the objects.
For that reason injection methods without a needle are preferably
=suitable in the treatment of wooden articles requiring a long-term
and persistent:protection,~e.g.~the wooden elements of plant sup-
ports (corrective frames, posts) in professional horticulture.
Another important advantage achieved by using needle-free injec-
tion devices is the saving in working time. These devices allow
rapid working, they are robust and relatively: long-lived. Since they
are sterilizable by autoclaving they can also be used in such active
substance administrations where freedom of viruses or risk of viral
infections is important, for example, in the cultivation of virus-free
species or in meristem multiplication.
The present invention will be illustrated in greater detail by the
following examples:
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Example 1
2.5 parts by weight _ : of powdery polyacrylic acid (Carbopol ETD
2050) was dispersed in 97 parts by weight. ~ of water. 0.5
-. parts . by weight of the active substance AI-fosetyl was added to
the suspension thus produced. The added active substance was
homogeneously distributed in the mass under constant stirring.
The active substance-containing aqueous acrylic acid dispersion
having a relative.viscosity.of 0.86 Pas (at 25°.C-according to
. -:.Brookfield LVF/measuring body)v.was thewfilled into a pressure- ..
- _v actuated needle-free' injection device (type Dermo-Jet) and injected
. ~:~ into' plant tissue at the base of a one-year-old raspberry sprout
(Fiubus idaeus) at a pressure of 8.1 bar.
Example 2
0.9 g of salicylic acid (resistance inducer for plants) was dissolved
in 500 ml of distd. water under heating to 30°C. 100 ml of .the
solution thus obtained was filled into a pressure-actuated needle-
free injection device (type Dermo-Jet) and injected into plant tis-
sue at the shoot axis base of a tobacco plant (Nicotiana tabakum).
