Follow the link to an interesting article on how neonictinoids affect honey bees. .
https://phys.org/news/2020-11-honey-bees-ingesting-pesticides-greater.html
Follow the link to an interesting article on how neonictinoids affect honey bees. .
https://phys.org/news/2020-11-honey-bees-ingesting-pesticides-greater.html
As part of my evaluation of my breeder queens I was also tracking the mite fall of two mixed breed hives. For the past week the two mixed breed hives have been having a daily mite fall of zero mites.
Previous readers know that my mite control plan is to treat my hives 3 times. One half dose of formic in mid-June, then a full dose of formic the last week of July and then a final fall cleanup treatment with oxalic acid vapor. On October 28th I performed the last oxalic treatment; a single treatment of 2 grams of oxalic. These hives were broodless at this time. Note: a single oxalic treatment of a hive, when broodless, should kill 95% of the mites in the hive.
In the three days following this treatment one hive has dropped 75 mites to the witness board and the second 29 mites. This shows that although the daily mite drop was low (actually zero) that there was still a large quantity of mites in the hive.
This end of season mite treatment will greatly improve the chances of these hives surviving winter.
Until recently mite resistance from grooming/chewing has
received little attention in the national bee magazines. I had previously used Purdue Mite Biter
stock with this trait. Last fall I
became aware of the availability of feral bee stock that also exhibited this
trait. I find it fascinating that
wild/feral bees had naturally developed a resistance to mites. NOTE: All honeybees exhibit chewing/grooming
to a limited extent. The PMB line and
this feral stock show enhanced chewing/grooming.
In 2020 I purchased two breeder queens from Dorothey Morgan
in Kentucky. One was of Purdue Miter
Biter (PMB) stock and the other of feral stock from mountainous areas in
Kentucky. Both stocks are known for
“chewing” on varroa mites. Dorothey has
not treated her bees for the past seven years since converting her entire
apiary to PMB stock. The feral stock
came from members of the Kentucky Queen Breeders Association. Testing by Dorothey and Dwight Wells had shown
this feral stock met or exceeded the level of “chewing” exhibited by the PMB
stock. Dwight is knowledgeable about the subject of
feral bees. NOTE: In 2020 Purdue
University did not produce PMB breeder queens for distribution due to the
COVID19 shutdown of their campus.
Dorothey also credits some of her overwintering success to not purchasing packaged bees and thus avoiding importation of any viruses floating around the general bee population (read that as from bees that were held in the California holding yards prior to almond pollination). Also, PMB and feral bee lines do not eliminate the mites, but reduce their numbers sufficiently so that hives can overwinter without need for mite treatments. Reaching an equilibrium between the parasite and host is how the Apis Cerana (the Asian honeybee) evolved to live with the varroa mite, although not through the same mechanism.
I wanted to assess how these two breeder queen hives were doing in
relation to mites. You could say I am
from Missouri, the “show me” state. I
wanted those two hives to show me that they had reduced mite counts. Utilizing witness boards was intended to
fulfill that need. Near the end of June,
I began daily inspection of the witness boards.
Initially I simply counted and recorded the number of mites on each
board. During the rapid growth stage of
the hives, I did not want to be removing 300 bees to perform alcohol-wash mite
checks. I was already opening the hives
on a weekly basis to take brood for queen rearing. Too much stress on a hive can result in queen
supercedure.
I also tracked mite counts in two overwintered mixed-breed
hives. One hive’s mite drop was rising
rapidly by the end of July (already greater than 20 mites/day), and
consequently I treated both mixed breed hives with FormicPro. Due to the treatments I did not include their
data here. The worst hive needed a second treatment at
the end of August when the mite drop again built up to 20 per day. (As a side note I requeened the hive after
the second treatment with a f1 PMB queen).
Here is the mite drop from the two breeder queen hives. I am presenting the data as 7-day moving
averages to smooth the curves. The
maximum daily mite drop for the feral queened hive was 10 mites and for the PMB
queened hive 23 mites. The maximum drop
for both hives occurred on the same day after the nighttime temperature got
down to the low 30s (lowest so far this fall).
A few comments/observations.
1)
It must be remembered that these were not
overwintered hives which would have a longer time frame for the mite population
to build.
2)
Recommended sticky board mite drop limits are
all over the place. I have found some
recommendations that mite drops of more than 10 or 12 mites per day indicate
the hive is in trouble and needs treatment. Other sources indicate daily drops
of up to 40 or 60 per day in the fall are the treatment threshold. I put the 12 mites per day limit in my
graph.
-BetterBee recommended a 12/day limit in August
-Brushy Mountain recommended a 60/day limit in fall
-PerfectBee recommended a 60/day limit in fall
-Virginia Cooperative Extension recommended a 40/day limit
-Ontario Ministry of Ag recommends a 12/day limit in August
3)
I performed two alcohol-washes (Aug. 21st
and Sept 25th) which yielded either 0 or 1 mite. These values are good for that time of year. Limits of 3% or 9 mites per 300 bees are normally
deemed acceptable. These two alcohol
wash checks show these chewing/grooming bees were controlling varroa mites as
desired.
4)
I haven’t
found any literature stating how to compare alcohol-wash results versus mite
drop counts.
5
6)
This uncontrolled test was a small sample of
only two hives. I would not jump to the
conclusion that “feral” queens, in general, are better than “PMB” queens. It may be true, but the small size of my test
prevents me from stating this is so. I
can’t determine whether the feral hive or PMB hive is doing a better job of
removing mites. Is the lower daily drop
of the feral hive a sign of better grooming performance or is the higher spike
during the cold spells a sign the PMB hive is doing a better job. I can’t wheedle the answer out of my limited
data. The IMPORTANT thing is that
the varroa levels of both hives are staying below both the alcohol-wash and
sticky board limits.
7)
My initial thought was that the two spikes in
the mite drop at the end of the summer were attributable to the end of summer
decline in brood rearing and cooler nighttime temperatures resulting in the
bees clustering. But after looking at
the nighttime temperatures it seems that nighttime temperature was the primary
factor in both spikes. The first spike occurred when the temperature
dipped to the high 30s (Sept 19th, 39F). The second bigger spike occurred when
nighttime temperature dropped to the low 30s (Oct 2nd, 32F). Mite
drop rose following each cold spell, usually several days in length, and began
declining as the nighttime temperatures warmed again. The maximum height of the
bump up occurred a few days after the cold night due to the damping effect of
the 7-day moving average used to smooth the curve. I
assume the colder temperatures are causing the bees to cluster and results in
enhanced grooming/chewing. A third cold snap (Oct 19th, 25F)
did not result in a mite drop spike. Why
the difference?
At the end of July, I started gathering all mites from the
witness boards and examining their legs for evidence of chewing. I have had no formal training in this
process, but simply looked for severed legs or missing edges on their carapace
(shell). I was using a low cost/low magnification
digital microscope which may have hindered the accuracy of my
observations. In addition, I did not
think of looking for severed antenna that are located between the eight
legs. About 5% of the dropped mites were
alive and moving their legs, 45% were
dead, and 50% had chewed legs and dead.
Both the PMB and feral hive drops exhibited roughly the same 50% chewing
rate. If I assume all of the dead mites
were due to natural mortality (this assumption is highly questionable), then I
could surmise that the “chewing behavior” had roughly doubled the mite
mortality.
The onset of colder nights (~ <40F) also resulted in finding no live mites on the witness board the following morning. When nighttime temperatures warmed back up live mites again appeared on the witness board. My thought is that the live mites that are on the witness board die of exposure during the night without the warmth of the bee cluster. Are the live mites falling to the witness board simply because they lost their footing or due to grooming? I can’t answer that question. So if mites are dislodged by either “chewing” or grooming or simply losing their footing they will probably die during the winter if they drop to the floor of the hive.
Now playing with the data a little. The graph shows a daily mite drop of roughly
8 mites per day (average of the two hives).
Taking away the 50% of mites showing chewing that leaves 4 mites per day
which would be considered natural mite drop do to mortality. Natural mite mortality runs about 0.5%. Therefore, there is about 800 mites in each
hive (4/0.005=800). Based on Randy
Oliver’s mite program a hive with 800 mites in mid-October should NOT have a
varroa induced crash. That makes me very
hopeful about this potential solution and confirms in my limited way that these
bees can survive with no treatment.
Overall, I am happy with the performance of both hives/queens
and will be taking these two hives through winter untreated. Assuming they survive (and with these low
mites loads they should survive), I will track mite drop through another year
to see how they cope with the longer period for mite reproduction.
I would say both the PMB and feral queened hives have
controlled the mite build up as advertised.
My only reservation of my observations is that they were not of
overwintered hives. Given the fact that
Purdue’s and Dorothey’s apiaries have been untreated for years puts that issue to bed and these queens will continue to be my focus for mite control next year.
From these breeder queens I have put about 50 queens into winter nucs. Next year I will monitor a few of these f1 queens (first generation) to see if they control the mites to the same extent. I would expect them to be not as good because this year’s drone population in my apiary was not all of PMB/feral genetics and therefore there would probably be a dilution of the “chewing trait”. I expect it will take several years to improve my entire apiary to equivalent performance and for me to be able to stop mite treatments. This problem of dilution also occurs with all improved bee lines (VSH, Minnesota Hygenic, Russians, etc.). Once you make the decision to improve your apiary you need to stick with it for several years to counter the genetic dilution effect that occurs due to the honeybee queen’s mating behavior. Purchase of package bees/queens also adds to the dilution. Its everything or nothing.
This article was found on the US National Library of Medicine website. Written by a Chinese doctor this article provides anecdotal information that Chinese beekeepers near Wuhan, China have not contracted COVID-19. The implication is that bee venom somehow provides immunity to the virus.
Next Saturday, October 17th, will be the October ECWBA meeting. The meeting will be about winter preparation. The meeting will be at the Rushford Meadery near Omro starting at 9:30AM. Due to a spike in Covid19 masks are strongly recommended.
PS-the next 3 days appear to be the last opportunity for pre-winter feeding. After that temperatures will be too cool for syrup uptake.
Dan Ziehli, the state apiary Inspector, for our area has been replaced by Charlie Koenen. Charlie's contact information is:
Charlie Koenen 608-444-3209 Email: charlie.koenen@wisconsin.gov
The following link may also be useful:
https://datcp.wi.gov/Pages/Programs_Services/ApiaryBeekeepingInspections.aspx
Note: It costs $50 for a visit by the state inspector.
Many beekeepers perform a one time varroa mite treatment using oxalic acid in addition to a late summer treatments. The idea is to perform this last of the season's (also called a cleanup treatment) treatment AFTER the queen has stopped laying and all brood has emerged. When this occurs no mites are hidden inside brood cells and are therefore exposed and susceptible to the oxalic acid vapors. Up to a 95% mite kill is possible at this time. The bees will go through winter as mite free as possible.
I had occasion to be inside several hives and nuc yesterday, October 6th. All still had capped brood. So it is still not time perform the cleanup treatment. It is better to wait to the last week of October or first week of November.
Here is a link to a short check list of things to do or check in preparation for winter.
Honey extraction is completed so I was able to get back to working on the bear fence. Today I completed the fencing for the mating yard. To make the size of the fenced in area manageable I had to move forty 5/5 winter nucs. Next was erecting the fence, which is composed of fiberglass posts and a electrical conducting tape. Finally was to wire in the solar energized power unit. It delivers a 3000 volt DC pulse about every 3 seconds. See below. This fencing protects my future; 40 Purdue Mite Biter or feral bee queens each in its own 5/5 winter nuc. Now on to the grafting yard where the PMB and feral breeder queens are located along with another 24 winter nucs.
View of entire fenced in area. This little pocket is in a little valley between two hills. It gets sun in the winter, but is protected from winter winds. Ideal for wintering bees.
He’s back! I had
reported in June that a black bear went through my area and knocked over two
hives. Luckily the hives and queens survived. The bear seemed to be more
interested in honey than the brood boxes.
I even got 2 supers of honey off
one of the hives. That was June.
Now he’s back in September.
So far, he’s knocked over 7 hives, some twice, and destroyed 6 supers
full of honey in a period of about 4 days. A neighbor about 1 mile away had pictures of him on a trail camera. I had started to remove my honey
supers the day before, but in the case of those 6 supers I was a day late and a
dollar short. Here is a picture. The 3 supers on this hive were spread over a 100 foot radius! None of the frames were broken but the foundation will need to be replaced. Needless to say I
removed all remaining honey supers pronto!
But he is also knocking over hives that I had previously removed the
honey supers. So every morning I need to check every hive for damage. This puts a little excitement into my retirement.
Wildlife is the property of the State of Wisconsin; so I
headed in that direction for relief.
After working through the DNR bureaucracy I ended up with the USDA
Wildlife Service (a federal agency).
They are contracted by the DNR to administer the state program for
restitution for damage done by wildlife.
This is done on a county by county basis.
Surprisingly, they provided me with four sets of solar powered electric
fencing. It will remain in my possession
as long as I remain in the program.
Also, they (the DNR) will be reimbursing me for my honey losses next
June (payments are made only once per year.) I suspect it won’t be as much as I could have
sold the honey for, but it’s better than nothing. Of
course, there is always a catch. I had
to agree to allow one licensed bear hunter access to my property if asked. But since the bear density is so low in Green
Lake county the field agent doubted I will ever be asked. The second downside is that I must relocate my
hives so that they will all be inside the fenced in area. When the hives are protected the bear will most probably leave the area.
The agent was knowledgeable on the damage bears can do. But when I showed him photos and a bear foot print on a honey frame he instantly concurred the damage was caused by a bear.
So if you are having bear problems this is a potential solution. My agent was Steve Krueger out of the USDA Wildlife Services office in Waupun. He covers three counties. A different agent may cover your county, but Steve would be a good starting point. The office phone number is 920-324-4514. One catch is that you must have damage prior to making the request.
At the past few meetings Gerard discussed removal of the honey supers. Follow this link to videos of two methods.
As promised in the previous article, beekeepers Fred and Jon performed alcohol wash mite checks on the 4 hives on August 21st. These were 300 bee samples from the brood nest; frames with both capped and uncapped larvae. The samples were shaken vigorously for 2 minutes while the bees were submerged in alcohol.
Here are the results.
Hive A-0 mites! Feral
breeder queen hive, hive is 3 months old, no mite treatments
Hive B-1 mite! Purdue
Mite Biter breeder queen hive, hive is 3 months old, no mite treatments
Hive C-0 mites!
Overwintered 3 or 4th generation PMB queen; treated w FormicPro
3 weeks ago
Hive D-5 mites! Overwintered 3 or 4th generation
PMB queen; treated w FormicPro 3 weeks ago
Mite infestation percentages are:
Hive A-0
Hive B-0.3%
Hive C-0 POST FORMICPRO TREATMENT
Hive D-1.66% POST FORMICPRO TREATMENT
Conclusions:
1)
The FormicPro treatment of hives C and D reduced
the mite levels to well below the recommended treatment level of 3% (9 mites
per 300 bees).
2)
The hives with the feral and PMB breeder queens
are well below the 3% (9 mite) treatment threshold and therefore do NOT need
mite treatments!
The only caveat is that the two breeder queen hives are only
3 months old and not overwintered, and therefore have had less time to build
their mite levels. Although these
results are very positive I feel several consecutive years are required to prove
the mites are licked! Humm, maybe I am
from the show me state. On the positive
side my source for these queens has been treatment free for 7 years!
I have been watching the natural varroa mite fall from four
hives using screened bottom boards with witness boards. The main reason for doing this was to track
the mite fall of two types of mite biter breeder queens I had purchased. One a
standard Purdue Mite Biter (PMB) and the second a feral queen crossed with PMB
drones. Every day for the past two
months I have pulled the witness boards on all four hives and recorded the
number of live and dead mites dropped by each hive. I wasn’t actually comparing apples to
apples. The two breeder queen hives were
started in early June from nucs. The
other two hives were overwintered hives. The overwintered hives had 3rd generation PMB queens. Due to the difference in the hive populations and longer time period for
the mite population to grow, one would expect the overwintered hives to drop
more mites; which they did. Mite drops
have been recorded every day since June 27th.
Witness board partially withdrawn. It is fully withdrawn to allow easy counting of the mite drop.
Just prior to applying mite treatments to the two
overwintered hives I calculated the daily mite fall of each hive (based on a 7
day moving average).
Hive A-1.8 mites per day Feral breeder queen hive
Hive B-0.7 mites per day PMB breeder queen hive
Hive C-2.4 mites per day
One of the two overwintered hives with 3rd gen PMB queen
Hive D- 11.3 mites per day
Strongest of the two overwintered hives with 3rd gen PMB queen
The mite fall has been slowly increasing for all hives as the
summer has progressed. This would be
expected because the mites are continuously increasing in number as they
reproduce. I have previously read that
mite drops of more than 10 to 12 per day indicate a hive in danger of a varroa
caused crash.
Formic acid treatments are known to be hard on queens. Not wanting to risk my breeder queens at this
time I skipped treating Hive A and B for now. Hive
C and D were treated with a full dose (2 pads=1 packet) of FormicPro on July 29th. Here
were the results
In the first 24 hours after treatment Hive C dropped 59 mites and Hive D dropped greater than 200 mites. Mite drop was its maximum on the first day after treatment and declined afterwards. The mites dropping after treatment were all dead. Prior to treatment it was a mix of live and dead mites. Total drop for the 2 week FormicPro treatment period were 259 mites for Hive C and 443+ mites for Hive D.
Here is a table showing the mite drop.
Days after treatment |
Hive A |
Hive B |
Hive C |
Hive D |
1 |
1 |
0 |
59 |
200+ |
2 |
1 |
3 |
27 |
174 |
3 |
2 |
2 |
16 |
30 |
4 |
1 |
0 |
17 |
17 |
5 |
0 |
3 |
17 |
2 |
6 |
1 |
0 |
20 |
0 |
7 |
0 |
1 |
15 |
6 |
8 |
0 |
1 |
16 |
2 |
9 |
0 |
2 |
10 |
1 |
10 |
0 |
1 |
25 |
3 |
11 |
4 |
3 |
19 |
4 |
12 |
1 |
1 |
13 |
2 |
13 |
2 |
5 |
3 |
1 |
14 |
1 |
1 |
2 |
1 |
TOTAL |
14 |
23 |
259 |
443+ |
One thing that is puzzling me is the relatively low mite drop from the overwintered hives with the 3rd generation PMB queens. Are the genetics in the 3rd generation queened hives still having a negative effect on mite populations? Based on the Scientific Beekeeping Varroa model I would have expected the mite drop to be in the thousands. Just maybe these 3rd generation queens are contributing to my good winter survival.
Hive D exhibited less mite resistant behavior than Hive C. I plan on replacing Hive D’s queen with a
queen from one of my breeder queens after removal of the honey supers.
I also plan to do alcohol wash mite checks on all four hives for several reasons:
1) as a cross check on the sticky board
results, 2) to verify the mite treatments effectively did their job of killing
off the mites, 3) to verify the mite levels of the two breeder queen hives are really as low as indicated by the
witness board counts. I will report on these new test results when
completed.
What was especially encouraging from this little exercise
was that the two hives with Mite Biting breeder queens are not, to date, showing the sharp rise
in mite counts that normally occur in August.
Their mite counts are remaining low; 1-2 mites/day on average; well
below the 10 mite per day drop where treatment with miticides is
recommended. I will continue to track
the mite drops of all four hives through October. Normally mite levels shown by mite drop to
sticky boards or by alcohol washes sharply rise in August through October as
the hive’s bee population downsizes in preparation for winter. The
rise in mite counts isn’t because there are more mites; rather there are less bees and less brood cells for the mites to hide in. Therefore, the probability of a bee or larvae
getting damaged by a mite sharply rises.