Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CA 02295898 2001-04-12
EVAPORATOR FOR THE TREATMENT OF HONEY BEE DISEASES
AND UNDESIRABLE HIVE COINDITIONS
BACKGROUND OF THE INVENTION
Damage to bee colonies resulting from epidemic diseases caused by
mites has become a serious threat to bee stocks throughout the world. Aside
from
leading to decreases in honey production, the spread of these mites also pose
a
threat to any form of agriculture which relies on honey bee pollination.
US Patent 4,867,731 teaches a method for the detection of infestation of
bees with mites comprising placing a replaceable insert with an upwardly
facing
adhesive trapping surface with a spaced screen mounted thereover into a hive,
wherein the spaces in the screen are large enough for mites to pass through
(and
onto the adhesive surface) but too small for the bees to pass through. The
inventors
note that this method can also be used in combination with treatments for
evaluating
the effectiveness of various miticides or in combination with irritants, such
as
Fluvalinate strips or tobacco or dry grass smoke.
However, when treating honey bees with fluvalinate strips, up to 60
percent of the varroa mites, which fall onto the observation material placed
below the
colony, are alive. It has been observed that these still-viable mites can
survive without
food for up to 7 days. During this time period, mites Nnrhich fall from the
bees are able
to re-attach themselves to honey bees and re-infect the hive. Because not all
of the
mites are killed quickly when fluvalinate strips are used, but continue to
remain viable
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for up to 7 days, 20-30% of these mites become re-introduced into the honey
bee
colony, and may hasten the development of fluvalinate resistance. Furthermore,
fluvalinate is known to irreversibly contaminate all hive products including
wax and
honey. It has also been demonstrated that low residual levels of pesticides
can
contribute to mite resistance.
US Patent 4,876,265 teaches a process for controlling mites on honey
bees using 2-(2,4-dimethyl-phenylimino)-3-methylthiazoline or derivatives
thereof as
the active ingredient. The composition is applied to ifumigant strips or
prepared as a
concentrate. In use, the compositions are either fed to the bees or arranged
to drip
onto the bees.
US Patent 5,069,651 teaches a method and device for removing
parasites from bees which comprises forcing heated air into a hive such that
the
temperature within the hive is elevated to a temperature that is not tolerated
by the
mites but is tolerated by the bees. Specifically, the air within the hive is
heated to 120-
130 F for approximately 15 minutes. In some embodiments, vegetable oil is
sprayed
into the flow of heated air. The device is fitted on top of the bee hive and
includes a
thermostat for monitoring air temperature.
US Patent 5,162,014 teaches a method for treating honey bees infected
with mites comprising exposing the hive to a magnetic field which is greater
than two
orders of magnitude stronger than the magnetic field of the earth.
Formic acid has previously been used in liquid form to control mites in
honey bees (apis mellifera). Formic acid is known as; a desiccating material,
and has
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been widely used, by various methods, to control rriites within honey bee
colonies.
Scientific analysis confirms that a minute amount cif formic acid will occur
in pure
honey. Apis cerana is another strain of bee and the natural host for varroa
mites.
Varroa has always been exposed to low levels of formic acid in the honey of
apis
cerana making it unlikely that these mites will become resistant to this
material in the
future. In one instance, a cardboard-like material soaked with formic acid and
arranged to be inserted into a hive was developed. Others have used
cheesecloth
soaked with formic acid, containers with wicks, and formic acid in a gel. For
example,
US Patent 6,037,374 teaches gel compositions of forrnic acid and a gelling
agent. The
gel is used in various types of dispensers which allow emission of formic acid
vapor.
Alternatively, they note that the gel may be applied directly, for example,
with a
caulking gun. However, it is of note that while formic acid vapor is emitted
during the
warmer parts of the day, but levels of formic acid vapor dropped during coo@er
evening
hours using the gel compositions, meaning that the formic acid vapor is not
continuously applied in this method.
As will be appreciated by one knowledgeable in the art, application of
varying levels of formic acid vapors over a long period of time may be less
effective at
killing the mites while being detrimental to the honey bees' health. Clearly,
an
improved method for treating honey bees infected with mites is needed.
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SUMMARY OF THE INVENTION
According to a first aspect of the invention, there is provided a method
of treating honey bee diseases comprising:
providing a substantially air-tight reservoir containing a volatile material,
said reservoir having at least one metered opening therein;
placing the reservoir in contact with a bee hive; and
heating the volatile material in the reservoir such that a vapor is
produced from the volatile material, said vapor exiting the reservoir and
entering the
bee hive via said metered opening, said vapor having miticidal properties.
According to a second aspect of the invention, there is provided a
device comprising:
a substantially air-tight reservoir for storing a quantity of a volatile
material, said reservoir having at least one metered opening;
a heater for heating the volatile material; and
a control unit for regulating the heater.
According to a third aspect of the invention, there is provided a method
of treating honey bee diseases comprising:
providing a substantially air-tight reservoir containing a volatile material,
said reservoir having at least one opening therein;
placing the reservoir in contact with a bee hive; and
heating the reservoir directly such that a vapor is produced from the
volatile material, said vapor exiting the reservoir and entering the bee hive
via said
opening, said vapor having miticidal properties.
According to a fourth aspect of the invention, there is provided a device
comprising:
a bee hive;
a reservoir connected to the bee hive, said reservoir for storing a
quantity of a volatile material, said reservoir having at least one opening
for exit of
vapor from the volatile material into the bee hive;
a heater for heating the reservoir directly; and
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a control unit for regulating the heater.
One embodiment of the invention will now be described in conjunction
with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an exploded view of one embodiment of the evaporator.
Figure 2 is an exploded view of another embodiment of the evaporator.
tn the drawings like characters of reference indicate corresponding parts
in the different figures.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Described herein is an evaporator that is designed for effectively
applying volatile materials for treating honey bee diseases and/or abnormal
hive
conditions. Examples of these known in the in art include, but are by no means
limited to, for example, varroa mites, tracheal mites, nosema disease and
chalkbrood.
Specifically, the evaporator comprises a reservoir for storing the volatile
material, for
example, formic acid, which is heated so that vapor is released into the bee
hive. The
amount of vapor released is metered so that the formic acid levels introduced
into the
hive are not harmful to the bees but lethal to the mites.
Referring to the drawings, an evaporator 1 comprises an evaporation
chamber 10, a heat source 12 and a control unit 14.
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The evaporation chamber 10 is arranged to hold a quantity of a volatile
material, for example, formic acid, as described below. As will be appreciated
by one
knowledgeable in the art, the evaporation chambei- 10 may be composed of any
suitably resistant material such that the evaporation chamber 10 is not
corroded by
the volatile material. In some embodiments, the evaporation chamber 10 is
composed
of steel or a formic-acid-resistant plastic.
The evaporation chamber 10 includes a top 16 which is arranged to fit
securely and tightly onto the evaporation chamber 110. The top 16 includes at
least
one opening for exit of vapor into the hive. In one embodiment, the top 16 is
equipped
with adjustable metering holes 18 to allow escape of ithe liquid from the
container as it
vaporises. As will be appreciated by one knowledgeable in the art, other means
for
regulating the flow of vapor from the evaporation chamber 10 into the hive may
also
be utilized. In some embodiments, the evaporation chamber 10 further includes
an
absorbent material 20 onto which the volatile material is loaded, as described
below.
The heat source 12 provides controlledl heat directly to the evaporation
chamber 10. As a result of this arrangement, in use a small amount of heat
circulates
upward which increases the temperature within the bee hive. The heat source 12
may
comprise an electrical element or a small diameter tube, as described below.
As will
be appreciated by one knowledgeable in the art, iri this embodiment,
temperature
controlled liquid circulated continuously through the tubing provides heat for
the
evaporation chamber 10.
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The control unit 14 is used to regulate the temperature of the heat
source unit and, therefore, the temperature of the evaporation chamber 10. In
some
embodiments, the control unit 14 comprises a mechanical thermostat or
electronic
control circuit which is used to control the temperature of the heat source
12, as
described below. As will be appreciated by one knowledgeable in the art, a
fully
electronic system is more reliable and accurate than a mechanical thermostat,
although any suitable control unit known in the art may be used with the
evaporator 1.
The evaporator 1 shown in Fig. 1, in its operation, vaporises material, for
example, formic acid, placed inside the corrosion-resistant evaporation
chamber 10
which is covered with the top 16. As described aibove, the tight-fitting top
16 is
equipped with metering holes 18 with openings adjusted by a slide 21.
Specifically,
the slide 21 includes a plurality of holes 22 which are arranged to be aligned
with the
metering holes 18. The slide 21 is slidably mounted onto the top 16 such that
the
holes 22 can be aligned or mis-aligned with the meter=ing holes 18. In this
manner, the
amount of vapor released into the hive is controlled by the degree of
alignment
between the metering holes 18 and the holes 22. In the embodiment shown in
Figure
1, the evaporation chamber 10 has an inside volume of 500cc, adequate for
treating
several honey bee colonies for mites with formic acid without refilling. In
this
embodiment, the heat source 12 comprises 2 fifteen watt heating elements 26,
for a
total of 30 watts of available heating capacity, and the control unit 14 is an
electronic
thermostat 24 which regulates the temperature of the unit. As will be
appreciated by
one knowledgeable in the art, other suitable wattages and arrangements may
also be
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used. In this embodiment, the main body of the heat source 12 is constructed
of
heavy aluminium sheet metal to distribute heat from the heating elements 26
evenly
over the entire surface.
A further embodiment of the evaporator 1 is shown in Figure 2 wherein
parts of the evaporator 1 have been separated for identification. In this
embodiment,
the heat source 12 comprises a"U" shaped heating element 28 which has two
electrical connections 30. In this embodiment, the control unit 14 for
controlling
current to the heating element 28 is a mechanical thermostat 32. A thin pad of
insulating material 34 is placed below the heating element 28 to prevent heat
loss
from the bottom of the unit. Formic acid is introduced into the absorbent
material 20
which takes up approximately half the volume of the evaporation chamber 10. As
the
evaporation chamber 10 is heated, formic acid vapor is expelled through
adjustable
metering holes 18, as discussed above. Specifically, the size of the metering
holes 18
is adjusted by moving the slide 21 to open or close the holes 18. The top 16
further
includes a groove 38 which fits on the edge of tlhe evaporation chamber 10 for
providing a tight seal, as shown in Figure 2.
In use, formic acid is placed in the evaporation chamber 10 of the
evaporator 1 and the top 16 is fitted onto the evaporation chamber 10. The
evaporator
1 is then placed in the hive and the slide 21 is positioned such that the
desired
amount of vapor will exit from the metering holes 18 when the evaporator 1 is
in use.
The control unit 14 is then used to set the temperature for the heat source
12. As the
heat source 12 heats the formic acid, vapor forrns which exits the evaporation
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chamber 10 via the metering holes 18 and is released into the hive. During the
first 24
hours of treatment with formic acid, with this inventior.i, extensive tests
show that 90 %
of the varroa mites, which fall onto the observation rnaterial placed below
the colony,
are dead, and the remaining 10% die within the next 24 hours. On subsequent
days of
treatment, 99% of the varroa mites falling onto the observation material are
dead. Any
varroa mites (in all stages of development), which are hidden underneath the
cappings with developing honey bee larvae, are ailso destroyed. These mites
are
subsequently removed by the worker bees after the fully developed bee emerges
from
its' cell. Extensive tests have demonstrated that any tracheal mites living
within the
trachea of the bees which are treated using the evaporator 1 die within the
first 24
hours of treatment with formic acid.
As can be seen, because of the heat source 12, the amount of
vaporised material produced by this invention is riot significantly affected
by the
normal atmospheric temperature variations which cain adversely affect other
systems
and applicators which depend primarily upon ambient conditions for their
operation.
Because of the added heat given off by the evaporator 1, formic acid vapor can
be
applied at temperatures as low as -10 C. This in turn improves effectiveness
of
treatment at low temperatures as honey bees cluster when the temperature falls
below + 5 C but treatment with formic acid, for mite control, is most
effective only
when the bees are not clustered but freely moving about on the surfaces of the
comb.
Thus, the additional heating of the hive by the heat source 12 provides fully
controlled
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CA 02295898 2001-04-12
evaporation for treatment administered even wheri the bees would normally be
clustered.
Thus, the evaporator I allows the operator to regulate the amount of
vaporised material introduced into a bee hive by incrementally controlling the
5 evaporator temperature and metering aperture size. As discussed herein,
continuous,
optimum, flow of formic acid vapour kills parasitic rriites much more
effectively than
other methods and systems, now in use, which administer peak amounts primarily
during daylight hours when there is adequate solar heating and only minimal
amounts
when there is little or no solar heating. During treatment for varroa and
tracheal
10 mites, the consistent rate of evaporation achieved with the evaporator 1
can safely
introduce a larger, more effective, volume of formic acid vapour into a bee
hive in a 24
hour period, without damaging the bees. By providing a continuous, optimum,
flow of
formic acid vapour for 2 to 4 days, it has been demonstrated during extensive
tests
that virtually no mites are left alive within the treateci colony. Thus, the
evaporator 1
makes more efficient use of materials than other prE;viously developed methods
and
systems by significantly decreasing the amount of formic acid required to
destroy
varroa mites and tracheal mites. With this inventiori, varroa and tracheal
mites are
destroyed with a shorter application time of formic acid. Furthermore,
significantly less
bee mortality occurs because treatment time is much reduced.
While the preferred embodiments of the invention have been described
above, it will be recognized and understood that various modifications may be
made
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therein, and the appended claims are intended to cover all such modifications
which
may fall within the spirit and scope of the invention.
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