Here are the winter survival statistics of a few ECWBA members that responded.
Back in an early 2019 ECWBA meeting the club distributed
four different varroa mite control methods that had been used by club members
and had successfully (in relative terms) controlled mites and limited winter
losses.
Another year has passed so we
surveyed a number of club members who had implemented these recommendations and
have tallied up the results.
Beekeepers A, B, and C used the mix of formic and oxalic
acid treatments (Method 2 below) and roughly followed the recommended
process.
Beekeeper A had 88% hive and
winter nuc survival.
Beekeeper B had 88%
hive and nuc survival.
Beekeeper C had 85%
hive and winter nuc survival.
Beekeepers D and E used the oxalic only treatments (Method 1
below) and roughly followed the recommended process.
Beekeeper D had 100% survival of hives.
Beekeeper E did not fare as well and had only
about 20% survival.
Critical to the use
of oxalic acid is that it must be applied 3 times one week apart in order to be
effective.
Beekeeper E had reduced the 3
applications to only 2 and paid the price.
Beekeeper F used the formic acid and Apiguard treatment mix
(Method 4 below).
Beekeeper F had 64%
winter hive survival.
Digging in a
little it turned out the Apiguard treatment is a 2 part treatment and must be
done in warm weather.
Due to cold
weather the 2
nd treatment did not get applied and Beekeeper F apparently
paid the price.
No one apparently used Method 3 below.
It must be remembered that in pre-varroa/virus days normal
winter survival ranged from 85 to 90%, so some losses can always be
expected.
Every beekeeper marches to his own drummer.
But it appears the 2019 ECWBA recommendations
if followed will yield good winter survival.
Shown below is a reprint of those recommendations.
VARROA TREATMENT RECOMMENDATIONS
At ECWBA meetings we frequently are asked “Tell me how to
treat for mites”.
Here are four
recommended courses of action.
We have
run these four methods through Randy Oliver’s Varroa model and all four should
control the mites sufficiently to get your hives through the year. This will
prevent winter collapse.
While the
spring (April) treatments are not absolutely necessary they will lower the mite
and virus levels during the spring buildup.
Using any of these four methods will prevent a mite level buildup from
year to year.
Method 1—Vaporized
Oxalic Acid only
This should be the lowest cost method (ignoring the cost of
the vaporizer) but is also the most labor intensive.
Oxalic acid treatments are also known to be
kinder to the queen.
NOTE: Applying oxalic acid vapor while
honey supers are on is not EPA approved.
-3
oxalic treatments a week apart beginning April 1
st
-Repeat
beginning June 1
st
-Repeat
beginning August 1
st
-Repeat
beginning October 1
st
Method 2-Oxalic
acid/formic acid mix
Rotating the oxalic and formic treatments hopefully avoids a
buildup of tolerance in the mites.
Formic acid is hard on queens, especially during extremely hot
weather.
Try to apply formic acid when
the initial four days of the treatment period are cooler.
Formic acid treatments are allowed while
the honey supers are present.
NOTE:
Applying oxalic acid while honey supers are on is not approved by the EPA.
-2
oxalic treatments a week apart beginning April 1
st
-A ½ strength Formic acid treatment
about June 1st. A full dose could be
used, but increases chances of losing a queen for not a big benefit.
-A full
strength formic acid treatment about August 1
st to 15
th
-A
single oxalic treatment about October 15
th
Method 3-Oxalic
acid/Apiguard mix
Rotating the oxalic and Apiguard treatments hopefully avoids
a buildup of tolerance in the mites.
Apiguard is not to be applied while your honey super are on.
The thymol in Apiguard will be absorbed by
the honey; making it inedible.
NOTE: Applying oxalic acid while honey
supers are on is not approved by the EPA.
-2
oxalic treatments a week apart beginning April 1
st
-3
oxalic treatments a week apart beginning June 1
st
-3
oxalic treatments a week apart beginning August 1
st
-An
Apiguard treatment beginning September 15
th
Method 4-Formic acid/Apiguard
mix
NOTE: Apiguard can not be applied while honey supers are in
place.
The thymol in Apiguard will
contaminate the honey; making it inedible.
-1/2
formic acid about June 15
th
-Full
dose formic acid about August 15
th