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If you just dropped in, we're working on the results of fogging bee hives with oxalic acid. 
That began back in October. Just go back a few pages using the links above.
Many of the images on these pages are thumbnails and clicking on them brings up a larger image?

Thursday November 10th 2011
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Wow!  Today is expected to be warm and tomorrow, warmer.  The Chinook winds are blowing and the arch is overhead.

The Alberta Beekeepers convention is over and for the first time in a long time, I did not go.

Young Mites /Total Mites

Day

Hive Number

1 2 3 4 5 6

15

Oct 26

2/3 2/19 8/16 20/39 8/21 1/12

16

Oct 29

0/6 0/11 - 5/22 12/27 0/13

17

Oct 30

0/6 4/16 8/21 6/18 6/22 4/18

18

Oct 31

0/10 0/28 22/42 14/30 30/91 1/13

19

Nov 1

0/5 0/9 12/24 7/22 18/31 1/4

20

Nov 2

0/3 0/5 14/27 11/22 3/10 0/1

21

Nov 3

0/2 0/1 6/11 11/22 5/9 0/6

22

Nov 4

 0/2 0/9 4/15 20/37 8/23 0/9

23

Nov 5

0/2 0/6 3/16 12/25 0/1 0/2

24

Nov 6

0/3 0/1 1/5 8/19 0/2 0/5

25

Nov 7

0/0 0/1 0/5 21/40 0/2 0/2

26

Nov 8

0/3 1/3 0/3 5/16 0/2 0/2

27

Nov 9

0/5 2/11 11/25 6/49 0/3 0/10

28

Nov 10

0/4 0/4 9/27 6/22 0/1 0/4
Totals   2/59 9/124 98/237 155/376 90/245 7/103
    3.4% 3.8% 41% 41% 37% 6.8%

Looking at the chart and the tables, it is clear that there was a distinct peak on day 18.  On that day, the drop almost doubled on five of the six hives.  Both young and dark mites increased, so... what was that about?

Hives three and four still look pretty bad and obviously have brood emerging still.

If we only count the dark mites, though, as I am sure many do, things don't look as bad, but, regardless, these loads are approaching threshold by any definition.

Hive three has not dropped nearly as many mites and did not respond with a heavy drop after fogging last time.  Maybe we did not do a good job on it.  That is a good reason to do several foggings in a row, with a reasonable spacing in time.  Two to three weeks looks ideal.  That way with high probability, any misses are caught unless there is a problem with the hive configuration and not just operator error.

Looking at my tabulation at left, it is obvious that I need a better way to sort the mites into young and old, but that I have some trends.  What seems unbelievable is that  the numbers for hives three and four average out at around 40% and hive five comes close to that. Contrasted with the results for the other three, and it seems obvious to me that there is useful information in counting the young mites separately. 

Would it not be nice to have an artificial intelligence program to do the job from high-definition photos of drop boards?

*   *   *   *   *   *   *   *  

Joe and Oene showed up around 4:20 with a huge truck and trailer and the oxalic fogging equipment.  We off-loaded the equipment and fogged the bees, finishing just as it grew dark.  I shot some video and will post it here after editing.  They then loaded the Bobcat and came in.

I should mention that we were concerned last time that, because we did not close off the entrances, we might have failed to give all hives a full dose last time.  This time we took no chances and observed the fog coming out the top entrances and from under the lids.  I'm not sure how much oxalic we used per hive, but I am guessing it was two or three grams at minimum.  My hives are in three and four boxes, so we figured to boost the dose.

The fog does not seem to have much effect on the bees.  They came out a bit, but soon went back in and I don't see any signs of kill.  If there were much kill, there would be lots of bees on the floor this morning and there were not.  Last time, we observed bees wandering around covered with white dust and acting perfectly normal.

Ruth came over and we all had supper.  Just as Meijers and Ruth were leaving, Fen and Elijah and Lorilee dropped by.  They had been held up by a train at our crossing and figured to kill some time with a visit.  We had a good visit, and then they were on their way, too.

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Friday November 11th 2011
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Here is the oxalic fogging video from last night (the second treatment). 
Download size is 27 MB.  It does not stream.

For those who want to examine the above data in detail and have all the charts in one place for comparison, here is the working file as of today.  It is a 111 KB Excel file.

Young Mites /Total Mites

Day

Hive Number

1 2 3 4 5 6

15

Oct 26

2/3 2/19 8/16 20/39 8/21 1/12

16

Oct 29

0/6 0/11 - 5/22 12/27 0/13

17

Oct 30

0/6 4/16 8/21 6/18 6/22 4/18

18

Oct 31

0/10 0/28 22/42 14/30 30/91 1/13

19

Nov 1

0/5 0/9 12/24 7/22 18/31 1/4

20

Nov 2

0/3 0/5 14/27 11/22 3/10 0/1

21

Nov 3

0/2 0/1 6/11 11/22 5/9 0/6

22

Nov 4

 0/2 0/9 4/15 20/37 8/23 0/9

23

Nov 5

0/2 0/6 3/16 12/25 0/1 0/2

24

Nov 6

0/3 0/1 1/5 8/19 0/2 0/5

25

Nov 7

0/0 0/1 0/5 21/40 0/2 0/2

26

Nov 8

0/3 1/3 0/3 5/16 0/2 0/2

27

Nov 9

0/5 2/11 11/25 6/49 0/3 0/10

28

Nov 10

0/4 0/4 9/27 6/22 0/1 0/4

1

Nov 11

0/46 2/8 62/164 3/48 0/4 0/20

I didn't wait 24 hours after the fogging to count the drops.  I stuck to my schedule already underway and pulled the boards at 9:30 AM. 

Since the treatment was at about 5 PM yesterday, this count is for the first 16-1/2 hours after treatment, plus any natural drop that happened in the previous 7-1/2 hours. 

I suppose I could adjust the numbers to a 24-hour basis, but to do that I would have to assume that the drop is linear over time after the fog, and who really knows?  I think I'll just stick to an honest count and report the timing of the counts.

Once again, I noticed a high proportion of very dark mites in the drop right after the fogging.  I have seen this previously in the period immediately after various mite treatments and indicates that we are hitting the otherwise long-lived mother mites hard.

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Saturday November 12th 2011
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We did not get any snow, yet, and the temperature is above freezing.

I'm looking forward to counting mites today, in about an hour and a half, and then Jean and family are coming by for a visit.

I decided to revert to a larger font today to see how that looks.  What do you think? Write me

I was up early today and wrote to BEE-L in response to a very reasonable reply there.  I have enhanced the response a bit since it was posted to the list, but not materially.

> Unbelievable, the way you apply oxalic acid, without any protection for your health

I forgot to label the video thusly, as requested by my friends/accomplices:

For Your Entertainment Only.
Not a Recommendation.
Don't Try This at Home, Kids
 - Actions Performed by Professional Stuntmen -

My video is not a recommendation and neither is what follows. Oxalic acid under many conditions can be very nasty and dangerous.

The following is my opinion and based on my own experience. It is not in conformity with many official recommendations, which, again in my own opinion and those of other smart beekeepers I know, are alarmist and over-cautious and actually counter-productive because they emphasize minor risks and thereby conceal the major risks.

> http://www.youtube.com/watch?v=ae8VIFy8YOA&feature=related

Nobody is going to get injured following the instructions for the Varrox verdampfer,  unless, of course the battery blows up in someone's face when attaching and disconnecting it in the manner shown due to the accumulation of hydrogen inside the cells.

The procedure shown, using clips on the terminals, is is not in conformance with battery safety guidelines as I know them! Having the top blow off a battery and right in one's face is not a pleasant event. This, I can testify from personal experience having had a battery in a 1964 Cadillac blow up in my face, showering me with hydrochloric acid. Somehow, it all worked out OK.  I can't even recall damage to my clothes, but that was decades ago.

Seriously, what was shown in the video I offered was an ad-hoc performance and was a one-time application, performed by knowledgeable and careful individuals with first aid experience and resources at hand -- and not done by an uninformed and unsupervised employee, alone and far from assistance.

FWIW, he sort of application demonstrated, albeit in a more organized and less haphazard form has a history of about a decade on many thousands of hives in sequence, with no reports (AFAIK) of harm to the applicators.

In this case, bare hands were safer than gloves because the acid can be seen and felt. There was no rain or snow to wet the acid powder. As for fumes, we had a breeze and were able to stand clear, although maybe it does not look like it.

Masks hinder communication and present a hazard in themselves and offer little real protection. The best protection is to stand upwind, and confine the fog to the hives. (More on this below).

If this treatment were being done on more than 25 hives or by employees, I am quite certain that measures would be employed to reduce exposure and risks. Whether the employees would use all the equipment supplied once out of sight is another question.

From my experience with oxalic acid, going back to before it was used in beekeeping, and what I can learn, the risks from oxalic acid in occasional and light exposure are mostly related to the caustic effects on skin, eyes, and lungs. Toxicity is not a real issue in casual exposure to the product.

Skin contact is no issue as long as it is time-limited and there is minimal moisture involved. Rain, for example or even dew would alter the situation, as would snow.

However, in the presence of water and in the case of prolonged contact skin injury is likely. With bare hands, there is a warning by a stinging sensation, especially at any slight cut or cuticles and the solution is to simply wash it off.

> and leaving all the holes open (effectiveness)!

As this application was experimental ,we wanted to observe and verify the distribution of the fog through the hives. On the previous application, a month ago, we did not do so and have since wondered. The acid is cheap, so we used a bit extra to compensate for the open entrances and the open holes. For what I can see, there is no need to close the hives, but it could reduce the amount of the fog in the yard and could be desirable for that purpose.

Confining the fog to the hives is an obvious protection for the operators. We would be more inclined to do that in a less ad-hoc application.

Again, the video was provided for entertainment, and my comments are my opinions and mine alone. The only advice I offer is to consult your local authorities and follow your local codes.

And, no matter where you live, don't connect and disconnect current-carrying  wires at battery terminals, especially when the batteries have been recently charged or discharged. Make and break connections remotely from the battery to prevent explosions and acid showers.

*   *   *   *   *   *   *   *  

As an addendum to the previous message which I wrote at 3:30 AM:

I should add that I am not particularly impressed with many aspects of the the units we used. They do work and work well, but it seems to me that the ergonomics are poor. These units are are heavy and awkward to maneuver and it is necessary for the operator to lean over repeatedly to load the acid and again to activate the fog.

A lot of work and expense has gone into the electronics of heat control and the fan setup, but the measurement and injection system is primitive.

It seems to me that it would not be that hard to design a dispenser which would push a measured amount of the powder into the heat chamber from a standing position and activate the fog.

The use of a 110 volt generator with a step-down to lower voltage adds bulk and noise. It seems to me that batteries charged from the vehicle alternator would be better in many ways. We used such a system for our hive loaders and it worked. There are some technical details to keep from running batteries too low and blowing alternators by trying to charge too many batteries too fast but these problems can be managed, especially for those who drive diesels and idle them constantly (one of my pet peeves).

The low-pressure blowers IMO could be replaced by compressed air pulses from a central compressor or tank and reduce weight and moment of inertia of the applicator units to allow easier handling and positioning. An entrance blocker sponge could be attached to the nozzle and fit into place each time the nozzle is pushed into an entrance.

The ideal air volume desirable for each hive to ensure distribution in large hives is probably about 2 cubic feet, since a triple has an interior volume of only about 4 cubic feet before the frames and bees are considered, so the actual empty airspace could be as little as 1 cubic foot. These units apply far more air than that, resulting in considerable fog escaping the hives. Perhaps if the hives are closed up, there is less air delivered, though.

When air is injected, using this system, as opposed to the verdampfer method, it should be obvious that the extra air has to go somewhere or no new air can be pushed in. Thus the need for either some open entrance or open top holes or a lifted lid when forced air is used.

The Varrox unit does not introduce outside air and relies on the natural convection in the hive, plus bee activity to distribute the fog, and from the literature that seems to be very adequate, at least in small hives.

IMO, where air is used to drive the fog through the hive, a short strong pulse of limited volume is more likely to be useful than huge volumes of low pressure air which send huge clouds outside the hives indicating waste and presenting an adverse working environment. The waste is not costly but anything that reduces the fog outside the hives cannot be anything but good.

Additionally, if an air delivery system could deliver smoke in advance of the fogging pulse to drive the bees up and loosen the cluster, that could be a good thing, too. A central air source could conceivably send smoke to the applicator units.

All in all, although a number of people have refined and re-designed the system demonstrated, it has not come a long way from the early European designs and the mobile multi-hive unit that Cor Dewitt first built in Canada and presented to our 2002 convention. The construction is more sophisticated, but the basic design is unchanged.
http://www.honeybeeworld.com/diary/articles/cor.htm
http://www.honeybeeworld.com/diary/articles/cor2004.htm 

*   *   *   *   *   *   *   *  

Here are the daily drops.

Young Mites /Total Mites

Day

Hive Number

1 2 3 4 5 6

15

Oct 26

2/3 2/19 8/16 20/39 8/21 1/12

16

Oct 29

0/6 0/11 - 5/22 12/27 0/13

17

Oct 30

0/6 4/16 8/21 6/18 6/22 4/18

18

Oct 31

0/10 0/28 22/42 14/30 30/91 1/13

19

Nov 1

0/5 0/9 12/24 7/22 18/31 1/4

20

Nov 2

0/3 0/5 14/27 11/22 3/10 0/1

21

Nov 3

0/2 0/1 6/11 11/22 5/9 0/6

22

Nov 4

 0/2 0/9 4/15 20/37 8/23 0/9

23

Nov 5

0/2 0/6 3/16 12/25 0/1 0/2

24

Nov 6

0/3 0/1 1/5 8/19 0/2 0/5

25

Nov 7

0/0 0/1 0/5 21/40 0/2 0/2

26

Nov 8

0/3 1/3 0/3 5/16 0/2 0/2

27

Nov 9

0/5 2/11 11/25 6/49 0/3 0/10

0

Nov 10

0/4 0/4 9/27 6/22 0/1 0/4

1

Nov 11

0/46 2/8 62/164 3/48 0/4 0/20

2

Nov 12

2/131 0/28 34/404 4/190 0/7 2/85

In examining the boards, I again noted the preponderance of dark, well formed mites over the paler and less distinct ones.  This phenomenon has not been distinct in the natural drops I have been counting before the treatment and after the first one wore off.

I should again emphasize that I am still learning and my ability to distinguish is limited and approximate at best.

It is interesting to note that both mature and immature mites tended to be found in groups, often separated by several inches, suggesting that they are not at all evenly distributed through the cluster.  Randomness would predict some clumping, but what I am observing seems more coherent than patterns resulting from randomness.

Here's a short YouTube varroa video.

 

Evaluation of Fall 2011 Oxalic Fogging to Date
and Discussion

It is clear that there are problems with relying on one fall treatment with oxalic, whether drizzled or fogged, since hives vary widely in the amount of brood they may have and whether they go broodless or not.

This fact may account for success in some regions and in specific operations where management, climate and choice of bee may result in distinct and reasonably long broodless periods.  So far, I am not seeing broodlessness across the board -- yet at least.

My conclusion, thus far, for October oxalic fog treatments is that they are not a reliable across-the-board measure, but are remarkably effective on some hives and simple to do.

What jumps out of the results, though, is that the average is not representative of all hives.

Is it worth doing a treatment before all hives are broodless?  I think so, to reduce damage and to clear the broodless hives of mites.

I also think that for small operations the Varrox device is probably as good a way as any for doing the job.  Small, inexpensive home-made pipe devices may be just fine, too.

Here are some links to info on simple, inexpensive vaporizer units:

Any exception to fall broodlessness at time of fogging allows a reservoir of varroa infestation to remain and grow in a yard during and after oxalic treatment, accelerating the reintroduction into the other hives, even in the unlikely case that they have been totally cleared of the pests. Hive three is a perfect example of the one hive that can compromise an otherwise successful yard treatment.

That is why a method of monitoring hives individually is desirable for any situation where "soft' methods are used in order to spot the exceptions.  Jean-Pierre Chapleau ran a drop board with a drawer under every hive and that is ideal IMO so that hives can be monitored individually.  Few people have followed his lead.  For commercial operators, the complication and expense is off-putting and there are cheaper chemical solutions available -- for now.  I don't know why hobbyists and side-liners don't adopt it, though.

Some strains of bees tend never to go broodless in fall and winter, while others may tend to have fairly long periods with no brood.  This period may also vary with location and season or climate, hive management practices, and also the strength  and timing of previous flows and state of hive provisions.  Hives which were requeened or superseded during late summer will often have brood later into fall than other hives in a yard.

This problem with lack of uniformity of results is the big issue with using "soft" controls and genetic solutions in large scale commercial situations.  Whereas chemical treatments like strips typically provide predictable and uniform control across the board -- barring mite resistance to the treatment or operator error -- "soft" controls and genetic solutions are always variable, and the degree of control may range from low numbers to almost 100% in the same yard at the same time, and also vary widely from one treatment event or location to the next.

Controls that achieve less than 90% efficacy and are not consistent can be helpful, but require closer monitoring and will need follow-up control measures far sooner than those with higher and more consistent efficacy.

Even with lower and less reliable efficacy, applying a control like oxalic -- or formic acid -- in rotation with other methods can delay the emergence if resistance to chemicals like fluvalinate, coumaphos and amitraz and enhance and prolong their usefulness.

How does fogging with oxalic in late October in my part of Alberta with my management measure up?  So far, it falls far below the observed efficacy and consistency of strips like Apistan, Checkmite+ or Apivar used in operations where the mites are not resistant to them.

With a second treatment, our oxalic fogging efficacy may prove to be better, but so far, it appears that exceptions like hives three and four will downgrade the otherwise excellent results in hives like hives one, two, four and five.

I'm thinking a third treatment may be required to approach the efficacy of strips, and even then, if the hives do not go broodless by that time, we will still fall short.

Strips have the advantage of being in place over two complete worker brood cycles (42 days) or 3 full mite invasion cycles (~13 days).  At the end of each 12-day period of being protected under cappings, emerging mites are exposed to the chemical.

I'm figuring the 12 days under cappings plus the day before (roughly) when the mother mite is invading the cell.  That adds up to ~13 days per mite reproduction cycle.

The effect of oxalic fogging seems to last only about two weeks per round.  Moreover, the concentration decreases over that time whereas the strips maintain relatively  consistent dosage over time.

FWIW, like any mite control, strips also work best when there is little or no brood in the hive, because fewer mites are protected by cappings.

Jean and Chris brought lunch around noon.  After lunch, I soldered in new capacitors into the defunct monitor, but that did not revive it.  I gave the old ones to Mckenzie for show and tell.

Ruth and Dave came over with Ruth's non-working Internet hub and laptop.  After several hours of repairs and updates, they left with a working system.

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Sunday November 13th 2011
Click to visit November pages from previous years: 2010, 2009, 2008, 2005, 2004, 2003, 2002, 2001, 2000, 1999

Young Mites /Total Mites

Day

Hive Number

1 2 3 4 5 6

15

Oct 26

2/3 2/19 8/16 20/39 8/21 1/12

16

Oct 29

0/6 0/11 - 5/22 12/27 0/13

17

Oct 30

0/6 4/16 8/21 6/18 6/22 4/18

18

Oct 31

0/10 0/28 22/42 14/30 30/91 1/13

19

Nov 1

0/5 0/9 12/24 7/22 18/31 1/4

20

Nov 2

0/3 0/5 14/27 11/22 3/10 0/1

21

Nov 3

0/2 0/1 6/11 11/22 5/9 0/6

22

Nov 4

 0/2 0/9 4/15 20/37 8/23 0/9

23

Nov 5

0/2 0/6 3/16 12/25 0/1 0/2

24

Nov 6

0/3 0/1 1/5 8/19 0/2 0/5

25

Nov 7

0/0 0/1 0/5 21/40 0/2 0/2

26

Nov 8

0/3 1/3 0/3 5/16 0/2 0/2

27

Nov 9

0/5 2/11 11/25 6/49 0/3 0/10

0

Nov 10

0/4 0/4 9/27 6/22 0/1 0/4

1

Nov 11

0/46 2/8 62/164 3/48 0/4 0/20

2

Nov 12

2/131 0/28 34/404 4/190 0/7 2/85

3

Nov 13

0/114 0/47 10/293 0/94 0/9 0/78

Today is the second full day after the second oxalic fog treatment.  The boards are covered with dark mites and I only saw a few paler ones.  The drops are sufficiently high that I have had to adjust the maximums on the vertical axes of the charts up to 2,000, so they will look a little different now and are not directly comparable visually to previous charts shown on earlier pages, although the historical data is still the same.

I only saw several very immature mites on the board under hive three, so maybe it is about done with brood rearing. I hope so.    There were mostly tan-coloured mites in the 'young' count (left).  

Of course, an alternate explanation for no callow mites dropping in some hives, in the presence of continuing brood rearing would be that mites are virtually eliminated in those hives and therefore there is very little callow mite drop from emerging brood.  This would be the case in a mite-free hive with plenty of brood.  We have to compare the mite drop to callow drop to deduce whether this could be the case.  For hives two, five and six, this scenario is conceivable, but then, if they have brood how did we rid them of mites?  They obviously had quite a few and responded to treatment.  So that is not likely, unless, they have just resumed brood rearing now, and I doubt it.

I'm tempted to take several of the hives apart to see why they are so different.  Is any of them queenless?  I think it is too late in the season to do an invasive inspection.

At right is a shot of as drop board these days.  There is very little debris, some oxalic acid crystal, and many dark mites.

I have left the auger holes and the entrances open in hopes of discouraging further brooding.  I'll have to close the entrances again, though since in large hives, the bees are too high up to drive mice out and they tend to come in for the winter.  I could use mouse screens instead, though, I suppose.  These hives are sufficiently warm and air-tight that some ventilation is necessary for good bee health.

Below are some tables from an interesting study about queen mating, acceptance and pre-oviposition period in varroa infested colonies.  I wonder if this was a factor in my bad queen experience this year.  I did not measure the mite levels, and assumed that they were quite low.  I suspect that I was correct.  Otherwise, they would be much higher now, but I really don't know.

Here is a treasure. This paper discusses oxalic acid and its effects on bees, varroa and mammalians intelligently.  There are a lot of scary claims made about oxalic acid, but it seems to me that this product is quite safe when used with a tiny bit of common sense, and that the risks of making a huge error of judgment are vanishingly small for most of us.

Here is an article on the same topic which is a bit more fun.  Enjoy.  Don't worry.  Be happy.

I did get some feedback.  People like the larger font.  I may go back and change the formatting of some past pages.  We'll see.

One thing, though: my rule is not to delete or change what I wrote after it has been up for a week or more.  I fiddle constantly with content from the past few days to better express and clarify my thoughts, but part of my goal in writing this is to expose my own thinking even if I was really, really, wrong.

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Monday November 14th 2011
Click to visit November pages from previous years: 2010, 2009, 2008, 2005, 2004, 2003, 2002, 2001, 2000, 1999

We are still evaluating the risk to beekeepers from evaporating oxalic acid.  Here an clip from the European perspective, from "Evaporation of oxalic acid – a safe method for the user?"  which is a link on this page.  The paper is discussing both evaporation (also called fogging or sublimation) and spraying in sugar solution.  I suggest that anyone using OA should read the whole paper.   The picture is courtesy this page

"20 participating beekeepers, 244 oxalic acid treatments In October 2001 in the context of the presented study, 20 beekeepers were accompanied along their oxalic acid treatments. 10 beekeepers used the Varrox® evaporator ... 10 beekeepers applied the spraying procedure with a 3%-solution of oxalic acid ... During this entire work time the sampling device was filtering oxalic acid particles from the air surrounding the working place...

"...Which risk remains? By an evaluation of the endangerment by oxalic acid we have to differentiate between a systemic effect and a local-irritation.

"'Systemic' means that oxalic acid is taken into the blood circulation, where it can reach the kidneys and conceivably cause damage by the formation of calcium-oxalate stones. This indirect, not immediately perceptible effect, distinguishes oxalic acid from other organic acids, e.g. formic or lactic acid, and justified past skepticism regarding user security.

But: The adherence to the exposure-limit protects the beekeeper against such systemic effects. The available results show that a systemic effect of oxalic acid to the beekeeper is not to be expected regarding both procedures. This is true without special preventive measures, e.g. carrying of a protective mask. (Emphasis added).

To my mind, spraying a solution is more likely to expose the beekeeper to oxalic in solution and in droplets in the air than a careful evaporation.  In addition, spraying is far more invasive.  Interestingly, OA is in many cleaning products that do not advise special protection measures on their labels. 

I can see that if a beekeeper is doing many applications, especially if inexperienced and in a challenging or unfamiliar environment, that protective measures are advisable to control and reduce exposure.

However, given that OA is normally present in the human body and metabolized daily in measurable amounts from normal healthy foods, and that these applications, done properly over short periods of time should not significantly increase normal everyday levels in the body, I am personally comfortable with using minimal protection.

This is not advice.  Do your own research and obey any local regulations.

Here are today's results.  I am only seeing young mites in hive three and I saw several males there, so I think that is the clincher that brood is still emerging.

Young Mites /Total Mites

Day

Hive Number

1 2 3 4 5 6

15

Oct 26

2/3 2/19 8/16 20/39 8/21 1/12

16

Oct 29

0/6 0/11 - 5/22 12/27 0/13

17

Oct 30

0/6 4/16 8/21 6/18 6/22 4/18

18

Oct 31

0/10 0/28 22/42 14/30 30/91 1/13

19

Nov 1

0/5 0/9 12/24 7/22 18/31 1/4

20

Nov 2

0/3 0/5 14/27 11/22 3/10 0/1

21

Nov 3

0/2 0/1 6/11 11/22 5/9 0/6

22

Nov 4

 0/2 0/9 4/15 20/37 8/23 0/9

23

Nov 5

0/2 0/6 3/16 12/25 0/1 0/2

24

Nov 6

0/3 0/1 1/5 8/19 0/2 0/5

25

Nov 7

0/0 0/1 0/5 21/40 0/2 0/2

26

Nov 8

0/3 1/3 0/3 5/16 0/2 0/2

27

Nov 9

0/5 2/11 11/25 6/49 0/3 0/10

0

Nov 10

0/4 0/4 9/27 6/22 0/1 0/4

1

Nov 11

0/46 2/8 62/164 3/48 0/4 0/20

2

Nov 12

2/131 0/28 34/404 4/190 0/7 2/85

3

Nov 13

0/114 0/47 10/293 0/94 0/9 0/78

4

Nov 14

0/56 1/51 23/365 0/150 0/8 0/65

My counting of young mites is somewhat unscientific and that call includes any that look pale and soft, even if they are fully formed and have some colour.

The immatures and males invariably fall right below the brood patch.  Pale coloured mites can be found further away.  The dark ones can be found anywhere on the drop board.

I looked into my entrances today to evaluate the potential for using the Varrox or the various similar devices discussed above. 

On reflection, it seems to me that the only justification for having air blown in is that the evaporation can take place outside the hives for beekeepers with insufficient clearance under the frames or for combustible hives. 

BEE-L again.  I'm losing patience with overly cautious comments.

>> "The available results show that a systemic effect of oxalic acid to the beekeeper is not to be expected regarding both procedures. This is true without special preventive measures, e.g. carrying of a protective mask.

>Please read this sentence in its context

Actually I did, and that statement stands on its own. The paper discussed, as far as I could tell, two treatments, one where the beekeeper is spraying OA solution into the air and all over the place and one where the OA was being vapourized in a closed hive.

In neither case was there reason to fear an exposure sufficient to cause concern.

> and keep account of the subsequent section: Recommended preventive
> measures!

That is the usual ass-covering BS that civil servants have to append to everything so they don't lose their chance at a pension.

>See also Peter Borst' recommendation.

See above comments about civil servants :)

Seriously, that is all good info and IF you plan to break the rules, it is best to know what they are and why they were written.

Around noon, Ellen and I drove to Calgary for two consultations regarding tests she has undergone lately.  We were done and back home by five-thirty.

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Tuesday November 15th 2011
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I am seeing continuing high mite counts from the recent oxalic evaporation treatment.  Hive three continues to drop some pale-looking mites, but no males and no immature mites, so maybe it is finally broodless.  I have left the auger holes and entrances open to cool the hives a bit on the thinking that the humidity and confined warmth may be stimulating continued brooding.

Young Mites /Total Mites

Day

Hive Number

1 2 3 4 5 6

15

Oct 26

2/3 2/19 8/16 20/39 8/21 1/12

16

Oct 29

0/6 0/11 - 5/22 12/27 0/13

17

Oct 30

0/6 4/16 8/21 6/18 6/22 4/18

18

Oct 31

0/10 0/28 22/42 14/30 30/91 1/13

19

Nov 1

0/5 0/9 12/24 7/22 18/31 1/4

20

Nov 2

0/3 0/5 14/27 11/22 3/10 0/1

21

Nov 3

0/2 0/1 6/11 11/22 5/9 0/6

22

Nov 4

 0/2 0/9 4/15 20/37 8/23 0/9

23

Nov 5

0/2 0/6 3/16 12/25 0/1 0/2

24

Nov 6

0/3 0/1 1/5 8/19 0/2 0/5

25

Nov 7

0/0 0/1 0/5 21/40 0/2 0/2

26

Nov 8

0/3 1/3 0/3 5/16 0/2 0/2

27

Nov 9

0/5 2/11 11/25 6/49 0/3 0/10

0

Nov 10

0/4 0/4 9/27 6/22 0/1 0/4

1

Nov 11

0/46 2/8 62/164 3/48 0/4 0/20

2

Nov 12

2/131 0/28 34/404 4/190 0/7 2/85

3

Nov 13

0/114 0/47 10/293 0/94 0/9 0/78

4

Nov 14

0/56 1/51 23/365 0/150 0/8 0/65

5

Nov 15

0/49 0/90 6/270 0/128 0/13 0/63

The simple 12-volt evaporators which draw about 150 watts (12.5 Amps) from car batteries do the job very well and I am beginning to think that there is no need to spend a fortune and lug around heavy, noisy equipment.

In my case, the only question is whether the unit fits in the entrance and IMO, that is the only justification for using the external evaporators with blowers.  I checked and I don't have clearance enough on most hives.  Now, I ask, what is easier?

1. increasing that entrance and bottom clearance,

2. getting an expensive, awkward external vaporizer, or
3. designing a way to use the Varrox or similar unit at the entrance.

For me?  Probably number one.


 

Eight of the evaporator units ( Varrox Vaporizer [left] [instructions] and Heilyser [right]) cost around $1,000 at list price and the batteries and cables for power distribution and charging from a nearby vehicle could add another $400 (max) if one were to improve the cables over what is provided and add proper switches or timers and arrange to charge from a vehicle while fogging.

Loading and deploying eight units at a time could be quite simple, especially with a little redesign of the units, the power cords and adding some switching.  Load and place four, activate them using a timer, and install the next four while the first four are working, then pull the first four out and repeat.  There should be very little waiting around and I'm thinking that a yard of 24 should take only a half-hour to three quarters for one person. Heilyser has a crude diagram on his site.

As for battery capacity, for the Varrox, 12.5 Amps times 2.5 minutes adds up to a little over 0.5 Ampere-Hours per hive, so 100 hives would use 50 Ampere-Hours or half the capacity of one normal, new, fully charged car battery.  Batteries lose voltage as the charge is used up, though, so the could be a tapering off around that point.

If the battery is on charge during the process, say by jumper cables from a car, then there should be no problem and the charging circuit would keep the voltage at 12 volts and up to 14.5 when not under load.

The Heilyser electric unit is claimed to require about a minute to evaporate and the Varrox, 2.5 minutes, so I'm guessing that the Heilyser draws about twice the amps and needs heavier wiring.  It appears to built around a diesel glow plug.

I notice that there is sufficient voltage drop using the Varrox that, according to instructions, the time has to be increased from 2.5 to 3.5 minutes if the seven-metre extension sold for it is used.  Heavier wire would avoid that. Welding cable is flexible, tough, and not expensive and there are good connectors sold to fit it, but for single units, common power cord sold everywhere should be fine.  Let's do the math:

Proper voltages -- 11.5 to 14.5 -- ensure rapid heating and normal performance.  If the voltage drops, the heater warms more slowly and might not even get up to temperature if the battery is weak, excessive lengths of small wire is used or there is a bad connection.

A small change in voltage will have a noticeable effect on performance.  P=E2/R, where P is power, E is voltage and R is resistance.

Since the resistance of the circuit is roughly constant, then the power output varies with the square of voltage. 

R is nominally R=E/I or 12/12.5 or 0.96 ohms for most of these units.

Rounding that off to 1 ohm, then
For 12 volts, P=144/1 or about 150 watts
For 10 volts (low battery), P=100/1 or 100 Watts
For 14.5 volts (Charging battery) P=210/1 or 210 watts

So, we can see that a battery connected to a charging circuit will deliver double the heat output that a slightly discharged battery will.  Long power extension leads will drop voltage in the same manner that a low battery will unless a larger wire than that supplied as extensions is employed.

If the voltage at the evaporator is less than some minimum voltage, then the unit may never get up to temperature, and low voltages will cause delays at best, so the ideal is to try to maintain voltages of 11.5 or more by using charged batteries and adequate wiring.  Attempting to run too many units simultaneously off the same battery will also result in reduced voltages delivered to the heaters.

Assuming that we wish to run the evaporator at rated voltage of 12 volts, and wish to run 15 feet of wire extension from a battery providing 12.5 Volts, what minimum size of wire must we use? 

We can spare 1/2 volt (12.5-12=0.5), so we use the table (right) which I adapted from Wikipedia

Since we want to use 15 feet of double wire, (one hot and one return), and the voltage drop (loss) in the table is for ten-foot runs of a two-wire extension cord, we need to have 10/15*0.5=0.33 volts drop per 10 feet to have a half-volt drop in fifteen.

Looking at the chart, we see that of the common sizes available, either 10 or 12 gauge come close.  #12 AWG gives us 0.6 volts drop over 15 feet of extension and is smaller and cheaper, so that would be my choice.  12 AWG happens to be available in flexible power cord form at almost any hardware store, although, these days, the three-wire format is easier to find.  We only need two.

What if we wanted to run two heaters simultaneously at the end of that 15-foot extension?Then we would have to choose a wire with half the voltage drop from the chart which is based on one heater, so #8 would be our choice (0.157*2=0.314), seeing as #9 is hard to find and #8 is available everywhere close enough to ideal.

(Smaller AWG numbers mean larger wires and less voltage drop).

Warning: Batteries which have been recently charged or discharged may give off explosive hydrogen gas.  Never connect or disconnect wire with flowing current at the battery (causing sparks).  Instead do so, or use a switch in a well-ventilated space at a safe distance (several feet) from the battery.

Disclaimer: These discussions are not a recommendation to use oxalic acid or to use any of the evaporators.  They are merely a recounting of my thinking and my own activities.

*   *   *   *   *   *

Here is a link to the source of the real, bulletproof 5-frame nuc boxes (not the weak ones sold by Betterbee).  Click on the picture.

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Wednesday November 16th 2011
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From the forum:

Saw your link about EPS nucs. I have 50 of the BetterBee nucs. They are EPS, not the flimsy stuff they sell for their regular hives. They are holding up quite well. I've dropped a couple and hit one with the truck. Only got dents, no cracks or breakage. I'm not a fan of BetterBee but their nucs are good.

Thanks for the report.  I stand corrected.  I'll have to post a picture here of a BeeMax box I noticed the other day.  It has split open and I assure you that I have handled it with kid gloves, picking them up and setting them down as if they were full of eggs.  The problem is that the box is full of honey and the joints on these boxes are not strong enough to handle that much weight.  I share some blame for choosing the wrong glue, but frankly, I expect better.

Speaking of EPS boxes, I have received some queries about six-frame EPS boxes and wonder if it is worth investing in a mold.  The investment would not be paid back at the usual rate of amortization until 15,000 boxes were made. 

Six-frame boxes are ideal for summer splits that are to be wintered, usually indoors and used for production the following year.  Some use the five-frame boxes, but they are a td small for the north and also plug easily in summer.  The Tegart design was intended for wintering in the Lower mainland, a warm area in the southwestern tip of the country where smaller hives with fewer stores are successful. 

That design is also not stackable, whereas a six-frame box made like a ten-frame box would be and doubles could be made up.  I would not make floors of EPS, since wood is so much better, but lids might be a good idea.

Here are today's drops.  As we can see, the number of mites dropping is tapering off again as the treatment wears off, and (hopefully) the number of mites becomes depleted.  Again, we are seeing some callow mites, but no males or immatures in hive three. 

Young Mites /Total Mites

Day

Hive Number

1 2 3 4 5 6

15

Oct 26

2/3 2/19 8/16 20/39 8/21 1/12

16

Oct 29

0/6 0/11 - 5/22 12/27 0/13

17

Oct 30

0/6 4/16 8/21 6/18 6/22 4/18

18

Oct 31

0/10 0/28 22/42 14/30 30/91 1/13

19

Nov 1

0/5 0/9 12/24 7/22 18/31 1/4

20

Nov 2

0/3 0/5 14/27 11/22 3/10 0/1

21

Nov 3

0/2 0/1 6/11 11/22 5/9 0/6

22

Nov 4

 0/2 0/9 4/15 20/37 8/23 0/9

23

Nov 5

0/2 0/6 3/16 12/25 0/1 0/2

24

Nov 6

0/3 0/1 1/5 8/19 0/2 0/5

25

Nov 7

0/0 0/1 0/5 21/40 0/2 0/2

26

Nov 8

0/3 1/3 0/3 5/16 0/2 0/2

27

Nov 9

0/5 2/11 11/25 6/49 0/3 0/10

0

Nov 10

0/4 0/4 9/27 6/22 0/1 0/4

1

Nov 11

0/46 2/8 62/164 3/48 0/4 0/20

2

Nov 12

2/131 0/28 34/404 4/190 0/7 2/85

3

Nov 13

0/114 0/47 10/293 0/94 0/9 0/78

4

Nov 14

0/56 1/51 23/365 0/150 0/8 0/65

5

Nov 15

0/49 0/90 6/270 0/128 0/13 0/63

6

Nov 16

0/16 0/42 6/185 0/71 0/5 0/46

Nonetheless hive three continues to have merging brood and will present a problem unless given another treatment.

It is in this scenario, that having drop boards under every hive and small, easy to deploy evaporators would prove idea.  Of course, for commercial situation, this idea is a non-starter.  Commercials much prefer strips and to treat entire yards, not deal with a few stragglers like hive three.

On the other hand, it appears that hive five was pretty well cleaned up by the first treatment as there are hardly mites dropping.  It got down to one mite a day before the second treatment.

So, how many mites are/were there in these hives:

  1. on the day off the first treatment and

  2. on the day of the second treatment and

  3. now

Anyone care/dare to hazard a guess?   That is a really interesting question.  Can we deduce the answers, using all the information posted here in the past month?

Write your thoughts in the forum, please.  There are no prizes.

Let me go first and I'll pick hive five. 

From the table, we see it stopped hatching brood on Nov 5.  Did it start again sometime along the way?  We won't know until 12 days after it is sealed.  We now have 12 days without any callow mites, though, so we can deduce that at the time of the second treatment, the hive was without sealed brood and all mites were phoretic. 

Then a simple multiplier of 60 times the average natural daily drop (2 mites) over those six days leading up to Day 0 and the treatment, and I'd initially guess 120 mites total in the hive. (+/- 60).  i.e. 60 to 180 mites.

Why +/- 60?  Because that number depends on the estimated average lifespan of those mites and the range is 30 to 90 days, with some certainty, so I am choosing a multiplier of 60 to start.

If the lifespan multiplier should have been 90, not 60, then make that initial guess to be 140 and 100 mites respectively.  (I always used to use '100' as a multiplier for broodless fall hives).

However, going at this another way, since Day 0, we have dropped 46 mites in hive five.  Going back to our reference curves we should expect to have dropped somewhere around 55 to 70% of the phoretic mites by day 6 in a broodless hive, and we are pretty sure the hive has had no brood during that time.

If 55% have dropped after treatment, then the total load on Day 0 works out to have been 93 mites. (46/55*100)

If 70% are down, then the total load on Day 0 would have been 66 mites.  (46/70*100)

These numbers are within our other estimated range of 60 to 180 and suggest the multiplier should be ((93+66)/2)/2=40 days, not 60 in this case.  Nevertheless, all theses guesses are in the same ballpark.

I'll go with (93+66)/2=80 mites initial load on Day 0 of treatment number two for hive five.

And, if, for some reason our treatment does not match the reference treatments due to method or brood that we have not detected, then who really knows?

What have we proven? Nothing conclusively, but I think we have made a good guess that  the mite load at time of second treatment was about 80 mites, all phoretic.

Now what about the day of the first treatment?

It dropped 60 mites over two days going in, and normally, with no brood, I would have guessed 3000 mites (60/2)*100=3000, or using our new number from above, (60/2)*40=1200 mites.   So far, we have dropped 990 and think there are only fewer than 100 to go.  Not too bad for a wild guess.

It isn't that simple, though, due the the brood rearing that went on in the meantime, but, looking back, I'd guess 1,000 at time of first treatment.  Knowing about the reproduction rate and the drops and the time span, that is my educated guess.

Next...

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Thursday November 17th 2011
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The forecast is for some really cold weather over the next few days, plus snow.  Jean has planned to come down for a visit today, but I am thinking this might not be the best day for it.

*   *   *   *   *   *

At left is a rather poor shot of a varroa on a drop board, taken with my hand-held Fuji without proper lighting.  It serves to illustrate the point I want to make, though.

On a dry board, the mites fall flat and are easy to spot, but on a sticky board, they often fall on edge, making them almost invisible from above.  We often see pictures of mites from an angle that makes them look substantial, but they are actually very thin and a bit concave on the bottom. like an upside down saucer.  For a long time I could not see how they could wedge themselves up under the segments of a bee and become invisible there, but this picture illustrates how thin and flat they are.

*   *   *   *   *   *

Here are today's drops and charts.  The effects of the last treatment continue to bring down mites.  Hive three still has some emerging brood.

Young Mites /Total Mites

Day

Hive Number

1 2 3 4 5 6

15

Oct 26

2/3 2/19 8/16 20/39 8/21 1/12

16

Oct 29

0/6 0/11 - 5/22 12/27 0/13

17

Oct 30

0/6 4/16 8/21 6/18 6/22 4/18

18

Oct 31

0/10 0/28 22/42 14/30 30/91 1/13

19

Nov 1

0/5 0/9 12/24 7/22 18/31 1/4

20

Nov 2

0/3 0/5 14/27 11/22 3/10 0/1

21

Nov 3

0/2 0/1 6/11 11/22 5/9 0/6

22

Nov 4

 0/2 0/9 4/15 20/37 8/23 0/9

23

Nov 5

0/2 0/6 3/16 12/25 0/1 0/2

24

Nov 6

0/3 0/1 1/5 8/19 0/2 0/5

25

Nov 7

0/0 0/1 0/5 21/40 0/2 0/2

26

Nov 8

0/3 1/3 0/3 5/16 0/2 0/2

27

Nov 9

0/5 2/11 11/25 6/49 0/3 0/10

0

Nov 10

0/4 0/4 9/27 6/22 0/1 0/4

1

Nov 11

0/46 2/8 62/164 3/48 0/4 0/20

2

Nov 12

2/131 0/28 34/404 4/190 0/7 2/85

3

Nov 13

0/114 0/47 10/293 0/94 0/9 0/78

4

Nov 14

0/56 1/51 23/365 0/150 0/8 0/65

5

Nov 15

0/49 0/90 6/270 0/128 0/13 0/63

6

Nov 16

0/16 0/42 6/185 0/71 0/5 0/46

7

Nov 17 0/9 0/45 8/168 0/70 0/6 0/26

The strong effects of a treatment seem to last about a week, and taper down until, after four weeks, there is not much noticeable effect on the mites. 

This fact is easily demonstrated by doing another treatment and observing the spike in mite mortality. From the charts, it looks to me as if three weeks would be a good time to repeat the treatment, and maybe just a bit sooner. 

An argument could be made for treating at fourteen days, since that is around where the cumulative drop curve flattens, on average.  If the goal is to get maximum effect from the minimum number of treatments and if brood is ongoing in some hives, waiting until three or even four weeks might make sense.  If maximum  mite suppression without regard for the effort and the possible harm to bees is the goal, then  three or even four rounds every 14 days looks to me to be the answer.

It seems obvious that a lot of mites came out of the brood in the period since the first dose, as the hives ended brood rearing in that period and the mites could no longer find refuge under cappings, judging by the second spike, which is larger than the first. 

During the first treatment, all the hives had brood.  At the second treatment, only hive three appears to have had a significant amount of capped brood, protecting the mites.

A third application, hopefully in a week or two from now, should tell an interesting tale.  What we are hoping for is a response like the one we saw from hive five on the second application.  That hive dropped very few mites the second time, because the first application has already killed most of them.  If only all the hives had responded so well.

The problem is that we treated too early for some hives and some still had brood.  Nonetheless, there was a big benefit, and waiting longer would have been a mistake.  It is clear to me that several treatments are required for maximum effect.  It is looking like three to get adequate and uniform control.

I ordered a Heilyser electric evaporator yesterday.  I would have ordered more, probably eight, but there is no price advantage and I would like to see one before spending $700.

As soon as I mentioned the order, I got an email from a friend saying he has some for sale.  I'm thinking I should cancel?  He said that he had a lot of trouble making the setup work consistently and that by the time he did, his bees had suffered a depressing amount of damage.

(I am amazed at how many people are following this little experiment.)

Fogging with oxalic vapour is NOT a quick fix, like strips, and as we are seeing here, the results are far from uniform.  From the charts, I have to wonder if we botched the treatment on hives three and five.  I don't think so, but they did not get the expected sharp, immediate initial drop pattern.

We have not done a third shot yet, but can see that there are still a lot of mites in one of the six hives I am monitoring and these six are surrogates for the other 19 in the yard.  Odds are that at least one other hive must be worse.

OA vapour may not be workable as an only treatment for most commercial operators due to the many variables, but is definitely a good treatment to use in rotation to help forestall mite resistance to the various strips on the market.

*   *   *   *   *   *

The latest forecast for tomorrow night is minus twenty-eight.  That is minus 18 degrees Fahrenheit.

It turns out that they are talking wind-chill. and the real real temperature forecast is only minus twenty-four, still.  I hate the media preoccupation with wind-chill.  I like to know the real temperature, since that will tell me whether I need to plug in the van.  Either way, though, it looks like a good idea since both numbers are below minus fifteen.  The AMA says their call volume goes up as soon as the temperature drops to minus fifteen

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Friday November 18th 2011
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It's minus 17 this morning and there are several inches of new snow.  We have an appointment in Calgary at noon, so we have to make the trek, snowy roads or no snowy roads.  Before then, I expect to have the mite boards pulled and counted.  I wonder how this cold snap will affect the counts.

I have a bit of an index on this site, but maintaining it could be a full-time job, given the amount of ground I cover.  Fortunately, the custom search I have set up works so well, that there is little need for the index.  If there is anything you are wondering about, just dream up some words that are likely to be in a paragraph on that topic and try the search.  It is amazing.  There is also a bee-filtered web search available.

I went without a cellphone for a few months some time back after Bell screwed up my account and lied to me, then would not set it right, but last March, I saw a deal for a smartphone at Wal-Mart and went for it.

I got the bottom-end Koodo Pay-As-You-Go LG Optimus One for $150, on the 'tab", meaning I don't pay anything up front and 10% of my monthly bill reduces that total.  Moreover, they gave me a $100 gift card on the spot, and I was in business, with a $17/month fee for 50 minutes and no contract, except to pay the balance of the tab if I decide to quit Koodo. 

Right now, I am down to $96 on the tab.  I've upped my plan to unlimited time and free long distance for $45/month and added 2 GB data for $25 and added a call display and voicemail. 

This little thing reduces my need for carrying my Galaxy Tab around.  They are both Android and share the same apps and data, so I can use the phone when the larger unit is unhandy and the larger unit when I am doing a lot of reading.  I use my netbook so little now, I am about to give it away.  I bought a larger notebook for sit-down work since I don't need a small carry-around Windows computer anymore.

I have heard that the Optimus One is not as advanced as many smartphones since it has a slower processer and less memory, but it has been a rock-solid performer for me.  Jon has a EDO 4G I've used and I have used the iPhone, too.  Maybe they are a bit flashier and faster, but they are bigger and clunkier.  This little thing has a grippy non-slip case and is tough.  It is small and rounded and goes into my pockets easily.

I wonder about those $600 phones that have  a reputation for exploding when dropped and wonder what I would do if I signed up for one for $29 with a three-year contract attached and it got lost or damaged.  I've seldom had a phone for three years without something happening to it.  If I drop this one in the toilet, then I am out $50 and have to find another.  Optimus Ones are offered on Kijiji for $100, so there you go.

Here are today's results. There was snow on the boards and I had to wait for it to melt.  The snow presented no problems other than that.

I decided to do counts using just strong (3.0) reading glasses and the light from the magnifier, and compare those counts to what I see with the magnifier and the glasses in addition to the light.  I was surprised to see that there was a 10-20% improvement in accuracy with the additional equipment, even on very clean boards (Hive three had a relatively dirty drop board). 

I also could not distinguish the young mites without the magnifier.  I find the results hard to believe, but I know they are correct.

This indicates to me that two people counting mites are very likely to see materially different results and that most people are going to err by quite a bit on the low side and underestimate the mite loads. 

Hive Number 1 2 3 4 5 6
Reading Glasses & Light Only 3 19 60 61 3 10
Glasses & Light & Magnifier 3 22 73 66 3 12

Hive three still dropped two soft, pale mites, but appears to be pretty much finished with raising brood. 

The drop counts are reverting to natural drop levels, so it looks like time to treat one more time soon.

*   *   *   *   *   *

Ellen, Zippy and I ran into Calgary, leaving around 11 and returning by 3:30.  The roads were not too bad. 

I love my 2002 Dodge van.  I've been shopping Kijiji for an upgrade even though I don't need one.  A Chrysler Town & Country Touring model, all loaded, would be wonderful, I think, but getting out and buying one is a hassle.  Then I'd have to sell this one, and that could be a pain.  This one has 245,000 km on it and people are afraid of mileage.  I always buy high-milers.  They are a giveaway and these days a good vehicle should do 300,000 km with only a few oil changes and maybe a tune-up, a windshield or two and some tires and brakes. 

Of course, something serious could go wrong, but that can happen as easily at 20,000 km as at 200,000 km.  People don't believe that, but it is true.  The difference is that the dealer will fix (hopefully for free or close to free) the problem at 20,000 or even 99,000 km, and at 200,000 km, you are on the hook for the whole thing.  The advantage to that, though, is you get to choose who does the work, and when. 

What I ask is how much is a major repair?  $3,000?  I paid $3,500 for this van and it owes me nothing.  A new van can cost $3,500 a year in depreciation alone, and this old van is like new inside, very decent outside -- and a great ride besides.

It is minus seventeen right now, and minus thirty Celsius is predicted for Sunday.  That is getting really cold.  (-22⁰F).  Juanse says we're having an el Niño again.  That means a really cold winter around here.

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Saturday November 19th 2011
Click to visit November pages from previous years: 2010, 2009, 2008, 2005, 2004, 2003, 2002, 2001, 2000, 1999

I looked back on these pages with fresh eyes yesterday and can see that I am not really writing for casual visitors, so I put some clues at the top of this page.  People dropping by may well wonder what is going on, being faced with endless charts and babble about my life and occasional insights.  Regulars know enough, I hope, to skim down to the current entry.  Lately these pages have grown huge.  I'm here at home and it looks like I will be for a while.  I had thought I'd spend much of the winter in Florida and the south, but plans change.

Oh, well.  I am actually writing this for myself, and sharing with those with the tenacity to keep reading.  Maybe I should put more effort, though, into making things easier to find?  Nah.  If I did that, I would not have time for the real interesting stuff. 

Besides, did I mention there is a very effective and accurate custom site search?

I have thought, though, of writing for the bee magazines again, and adapting some of this material.  It already written and illustrated and I would just have to select, edit, and submit.  I always give permission to bee club newsletters when they ask if they may reprint excerpts.

Over the years, I have written many published articles, but I can only write what I feel inspired to write.  It's not that I haven't tried otherwise.  At one point, I was writing quite a few articles and even thought that I could make an income writing.  Writing does pay, and not too badly, and magazines are always looking for good material.  I have never been turned down. 

Well there was one magazine cover I submitted that the editor did not like as much as I did.  A hint of it is at right.  I thought that just a simple high-res shot of bees in an auger hole on an otherwise white [or wood grain] magazine cover would be cool.  Apparently not.

Click to go to The Sept 2000 article about this swarmI did sell a Bee Culture cover back in 2001, though.  A thumbnail is at left. The original picture which was used is much better.  Back then we did not have broadband, so uploaded pictures to my site were pretty skimpy.  At any rate, that magazine cover was shot with a 1.3 megapixel camera and it looked AOK!

I wrote a few articles on topics that interested me and all were welcomed, but it turned out after a while, that the magazine later wanted me to write articles on specified topics, or at least suggested it.  I agreed, but immediately got a bad case of writer's block.  I was asked to write about queens.  What do I know about queens?  I've raised many, bought many various strains and read the right books, but I still don't know anything about queens.  I was stuck, and I knew it would only get worse.

I only really know a few things, so I'm a whole lot better writing about my ignorance and trying to discover what I don't know -- like this varroa thing.  I think it might make a good article.

I went looking for that cover at Bee Culture's website and instead came across this snip at Science of Bee Culture - Vol. 1, No. 1.  It addresses the effect of high varroa levels on queen acceptance, a topic we recently discussed here.

"Initial levels of mite infestation estimated from samples of adult bees were classified as high or low. Five of the colonies with high infestations died within the first three weeks of the study indicating that the queen introduction failed without a successful supersedure queen being produced. A comparison of the death rate between highly infested and less infested colonies was statistically significant (Fisher’s Exact Test P = 0.05) (Fig. 1a). After three weeks, nine of the more infested colonies had lost the introduced queen and were in the process of producing a supersedure queen. One of the less infested colonies was superseding its queen. This difference in supersedure rate is statistically significant (Fisher’s Exact Test P = 0.007.) (Fig. 1b) After six weeks, of the 29 colonies in the highly infested group, 15 produced supersedure queens or were in the process of superseding (Fig. 1b), and of the 27 colonies in the low infestation group, 10 produced supersedure queens or were in the process of superseding. The difference after six weeks between the supersedure rates in the highly infested colonies compared to the less infested colonies approaches significance (Fisher’s Exact Test P =0.11) (Fig. 2a). We also compared requeening failures between the highly infested and less infested colonies. Both colony death after queen installation and supersedures were considered requeening failures. Of the 34 colonies in the highly infested group, 20 experienced queen loss and of the 27 colonies in the low infestation group, 10 experienced queen loss. The difference in the queen failure rate between highly infested and less infested colonies is significant (Fisher’s Exact Test P =0.04 (Fig. 2b).

Obviously varroa is bad for bees in more ways than one.  I wonder how high my levels were this summer.  I did not see mites, but apparently I was not doing a good job of monitoring.  I did look, but apparently I was not seeing the mites that had to have been there, judging by the current levels.  I should have done alcohol washes, possibly while the hives were open for splitting, but I hate doing that, and at that point every bee counts and 300 nurse bees is a big sacrifice.

All this goes to show that beekeepers should do drops on several hives in a yard from time to time and be sure that the boards are carefully inspected.  That is what we did while operating commercially a decade ago and we always had varroa well controlled in those days.  Failing that, an alcohol wash or sugar shake will give a hint.  (Note: Natural drops are hard top interpret early in the season when there is a lot of brood being reared and may understate the infestation).

Looking at drone brood does not give a warning early enough to be of any use at all.  It merely tells you that your bees are already in deep trouble, and perhaps past the point of no return.

Looking for mites on bees is a poor indicator, too.  By the time we see more than the (very) occasional mite riding on bees, the colony is already past the point of severe damage and, very possibly, a lost cause.

It is easy to skip monitoring, since preparing the boards, getting them into the hive, collecting them and then appraising them takes time and several trips, but the cost of not doing so is high.  Alcohol washes are inconvenient, too, but quite simple to do with the shaker jar, available at Beemaid.

i

We're at Day 9 today and I am thinking that the next treatment should happen on Day 14 or as soon after as we get some weather a bit above freezing.  By the forecast, there should be some suitable days mid-week.  I may be pretty busy, though, since Jonathan is coming up from LA for a visit about then and we may have to make some daily runs into Calgary, too.

Also, I am trying to get some of the Heilyser units from a friend, but the way it is going, I doubt I'll have them in time.  Meijers are happy to help out, but I think that I should get my own kit at some point.  I'd also like to evaluate the simpler devices.

Something that I must remember that I forgot last time is to smoke the bees up before fogging.  The smoking should be far enough ahead that the bees have time to warm up and loosen the cluster.

I think that with the air-driven foggers, that this step is less critical, but for the heated devices which just sit under the frames and give off vapour, it could be important.

Smoking in advance loosens the cluster so that the fog can reach more bees than if there is a tight cluster and makes sure they are not in contact or too close to the evaporator.

Here are today's results.  Hive two dropped a pale mite today and hive three dropped two.  Drops are slowly diminishing towards the natural drop level, but the effects of the last treatment are still apparent.

Hi Allen:

I have tried modifying bases to make it easier to insert the vaporisers. Unless you put a screen just under the bottoms of the frames, the bees build drone comb on them. This defeats the purpose of making a deeper space and the drones raised in them don't help either.

I did find that the cluster is roughly spherical at the bottom and this lets you put the vaporiser in at the side. If you put it in the middle the bees in the cluster contact it and a lot of the acid precipitates out on them. I just used a 1x2 the width of the base with a slot in it for the vaporiser handle to seal the base - no foam needed.

The vaporisers I made this year are meant for use with auger holes. They seem to work well enough. I use much less air than the ones you are using. I believe that the excess air drives a lot of the acid out of the hive and that can't be helpful.

Best regards

Donald

Hi,

Thanks for the insights.  Are the ones for auger holes like the ones that Dennis Murrel has on his site, or something different?  Do you have pictures?

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