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Offline caticind

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Varroa levels in tolerant colonies
« on: December 16, 2011, 12:05:08 pm »
Question for those of you who have achieved moderate varroa tolerance through whatever methods (small cell, comb replacement, splitting, SBB, organic acids, etc)

Do you still measure varroa levels?  If not, do you still take note of the incidence of varroa-carried disease, such as DWV, when inspecting?  What signs of varroa do you see in colonies that nonetheless survive year-to-year?

I am carrying out a no-treatment test on some hives.  Southern package bees, force-regressed on plastic small-cell, then waited 8 weeks and allow the following generations of bees to draw foundationless.  At least half of comb replaced each year.  Open screens at the bottom.  All hives split at least once with new queens open-mated.

The whole first year, no hive dropped more than 10 mites per 24 hours (to be expected).  The second year, results were the same.  I now have two third-year hives in this group.  Both dropped less than 5 mites/24 hrs in August. (All drops are natural fall, not accelerated).

However, as I was shutting hives down for winter, I did see a fair number of DWV bees in both third-year hives.  I have seen a couple occasionally in all hives, but this was definitely the largest number I've seen - at least a dozen.  I'll collect new info on mite-drops tomorrow, but as I am doing so I was wondering what you see in hives that you consider acceptably mite-tolerant without use of acaricides.

Is any appearacnce of DWV an indicator that the bees are losing out? Just a short-term event as brooding stops and the smaller cluster is hit by a lot of new phoretic mites, which while subside later? Or can I be reasonably confident, as long as I don't see a continuing increase in mite load, that the bees will handle it?
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Offline yockey5

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Re: Varroa levels in tolerant colonies
« Reply #1 on: December 16, 2011, 01:18:39 pm »
Interesting.

Offline caticind

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Re: Varroa levels in tolerant colonies
« Reply #2 on: December 17, 2011, 11:27:41 am »
Ok, so the first 24 hrs shows a definite increase in mite drop from August.  I counted about 50 mites (my board is not gridded, so there is uncertainty of perhaps 10%).  That is much higher than previously measured in this hive, but much lower than the "treatment" threshold for Fall in the South that my reference books suggest indicates a serious threat to survival.

My data is not so good for this time of year, though.  Previously I've seen low counts in October and said goodnight for the winter.  This is my first sampling in December, so these numbers need to be salted liberally.

I will count again tomorrow morning, as I think it generally requires 2 or 3 days of data to average out daily swings.

Any thoughts?
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Offline Michael Bush

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Re: Varroa levels in tolerant colonies
« Reply #3 on: December 17, 2011, 11:58:27 am »
>Do you still measure varroa levels?

I did while regressing.  I don't anymore.

>  If not, do you still take note of the incidence of varroa-carried disease, such as DWV, when inspecting?

I take note of everything...

>What signs of varroa do you see in colonies that nonetheless survive year-to-year?

An occasional deformed wing bee.  I uncap some drone now and then and look for mites.  I check the trays on the SBB now and then.

>The whole first year, no hive dropped more than 10 mites per 24 hours (to be expected).  The second year, results were the same.  I now have two third-year hives in this group.  Both dropped less than 5 mites/24 hrs in August. (All drops are natural fall, not accelerated).

Sounds good.

>However, as I was shutting hives down for winter, I did see a fair number of DWV bees in both third-year hives.  I have seen a couple occasionally in all hives, but this was definitely the largest number I've seen - at least a dozen.  I'll collect new info on mite-drops tomorrow, but as I am doing so I was wondering what you see in hives that you consider acceptably mite-tolerant without use of acaricides.

I see a few DWV bees.

>Is any appearacnce of DWV an indicator that the bees are losing out? Just a short-term event as brooding stops and the smaller cluster is hit by a lot of new phoretic mites, which while subside later? Or can I be reasonably confident, as long as I don't see a continuing increase in mite load, that the bees will handle it?

A lot of them might.  IMO a few doesn't.  DWV was around before Varroa, they just spread it faster.

"The biggest mistake of all is to continue viewing mites and other “pests” as enemies that must be destroyed, instead of allies and teachers that are trying to show us a path to a better future.  The more virulent a parasite is, the more powerful a tool it can be for improving stocks and practice in the future.  All the boring and soul-destroying work of counting mites on sticky boards, killing brood with liquid nitrogen, watching bees groom each other, and measuring brood hormone levels—all done in thousands of replications—will someday be seen as a colossal waste of time when we finally learn to let the Varroa mites do these things for us. "--Kirk Webster, "What's Missing From The Current Discussion And Work Related To Bees That's Preventing Us From Making Good Progress?"

"I consider counting mites as a way of evaluating Varroa resistance to be fraught with all sorts of shortcomings and difficulties.  It's very time consuming and hence the size of the apiary, the number of colonies tested, the gene pool, and the income available all start to shrink.  It's also very easy for the results to be skewed by mites migrating from other colonies or bee yards.  And it doesn't show which colonies are more resistant to secondary infections--a trait I consider very important."--Kirk Webster, "Commercial Beekeeping Without Treatments of any Kind—Putting the Pieces Together Part II"
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Offline caticind

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Re: Varroa levels in tolerant colonies
« Reply #4 on: December 19, 2011, 11:43:08 am »
Thanks for your reply, MB.  That's very helpful.

I'm definitely in agreement with you/your quote on the importance of looking at resistance to secondary infections.  I've got two goals with this trial:  To improve my ability to judge whether a hive will make it or not.  To further test the assumption that mite drops are a good diagnostic.

For instance, a two-day drop this weekend yielded 156 mites (I counted more accurately this time).  For a daily average of 78.  Higher still than my previous one-day drop.  But the number of mites in the hive cannot be increasing at this time as there is no brood.  Something else is going on that affects the number.  For instance, this time the bees were in cluster.  Perhaps they are grooming each other more.

On a bee list I read, there's an in-depth discussion of oxalic acid going on.  There is much more data backing it than my little experiment.  But the discussion has instead come to center on what mite drops actually indicate, if they vary from day to day, and subsequent colony sacrifices show that there is little correlation between daily drop and total mite population.  

The DWV is some cause for concern.  But this colony has been flamboyantly healthy in all other ways.  It produced a swarm and 3 splits, and absorbed a combine from a colony that was failing due to EFB, even cleaning out infected combs.

I will keep pulling counts on this hive for my own edification.  If the drops continue to vary, then I'll know that they are not very useful, as I'd have to spend days counting and averaging to get any kind of accuracy, when what I really need to know is what impact the mites are having on the health of the colony.
The bees would be no help; they would tumble over each other like golden babies and thrum wordlessly on the subjects of queens and sex and pollen-gluey feet. -Palimpsest

Offline Michael Bush

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Re: Varroa levels in tolerant colonies
« Reply #5 on: December 20, 2011, 06:12:19 am »
I'm definitely not against doing mite counts to see how things are going.  Kirks point, and mine in quoting him, is that it may not be the best measure of success.  Surviving, thriving and being productive are better as they are the result of many traits.
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Offline BjornBee

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Re: Varroa levels in tolerant colonies
« Reply #6 on: December 20, 2011, 11:34:03 pm »
I do random mite counts. And for special reasons such as testing breeder queens, etc.

I think mite counts are good for a couple resons. One, it allows you to deal with individual hives that have high mite counts. While many will do a mite count and either treat all or none, based upon the results, it would be better to do mite counts on those hives that have cause for a test (DWV, etc), then requeen any below par queen.

Mite counts have traditionally been done to do nothing more than justify chemical treatments. But any treatments needed for a hive, should also be reason for requeening and other IPM action.

If you did take mite counts every couple weeks on hives, you probably would find a couple things....

1)Hives within the same yard will have drastic different counts.

2) You probably will have hives exhibit two type counts throughout the year.

    a) Hive counts such as 1-5-3-8-4-6-7-5

    b)Hive counts such as 2-7-4-9-15-31-28-42

Hive "a" should be left alone. The bees are dealing with the mites. Raise queen from these hives.

hive "b" is a hive that will crash and probably die in winter. It is a hive that needs assistance. And that may include treatment. But also requeening. One should go hand in hand with the other. Why treat and do a temporary fix for a hive that will continue to fail.

So using mite counts to weed out your weakest genetics, to select your best queen to perpetuate, and also limit any needed treatments to only your hives needing it, are all reason to do some mite counts.
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Offline Solomon Parker

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Re: Varroa levels in tolerant colonies
« Reply #7 on: December 26, 2011, 01:29:51 pm »
Question for those of you who have achieved moderate varroa tolerance through whatever methods (small cell, comb replacement, splitting, SBB, organic acids, etc)
One can not achieve tolerance in my view while still using miticides.  Tolerance does not involve treatment.

Do you still measure varroa levels?  If not, do you still take note of the incidence of varroa-carried disease, such as DWV, when inspecting?  What signs of varroa do you see in colonies that nonetheless survive year-to-year?
I do not measure, never have.  I do note crawling bees and other signs of varroa.  I see the occasional mite, and find mites in drone brood between frames.

I was wondering what you see in hives that you consider acceptably mite-tolerant without use of acaricides.
Survival.

Is any appearacnce of DWV an indicator that the bees are losing out? Just a short-term event as brooding stops and the smaller cluster is hit by a lot of new phoretic mites, which while subside later? Or can I be reasonably confident, as long as I don't see a continuing increase in mite load, that the bees will handle it?
I usually see DWV crawlers in the spring.  After that, the problem seems to clear up. 

My philosophy is 100% treatment free, so no matter what happens, or what I see, it's up to the bees to make it on their own.  As the years march on, I see better and better winter survival rates.  This year looks on track to see better than 80% survive with no treatment or mite focused manipulation whatsoever.  Last year was 62% and the year before that was 30%.  I am especially interested to see the results of one hive that I have which appeared to have a very heavy mite load this fall with mites easily visible on bees and visible mites in worker brood.  But even if it does survive, all the other 10 hives didn't have such a load.  We shall see.
Solomon Parker
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Offline Poppi

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Re: Varroa levels in tolerant colonies
« Reply #8 on: December 26, 2011, 05:34:56 pm »
Solomon, are you saying two years ago you had a 70% loss (30% survival) and last year a 38% loss (62% survival) and this year you are looking at a 20% loss with an 80% survival rate???  WOW, if so, that's much worse than the 30 to 33% average annual loss nationally...   maybe I'm not reading you right, please explain if not...  thanks, John

Offline Solomon Parker

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Re: Varroa levels in tolerant colonies
« Reply #9 on: December 26, 2011, 10:20:49 pm »
That's all correct, depending on the significant figure.

Actually, if those hives nationally had been kept in the same way I keep mine (100% treatment-free) the loss would have been catastrophic.  So all things considered, I'm doing quite well.

I've actually been keeping bees a bit longer than that, though that encompasses the time since I restarted in my current location.  The year previous to those listed, survival was around 90%.  I had gone through the same sort of trend in the years from 2003 to 2008 and had achieved a stable population at that time.  Then I moved and the system had to re-acclimate.
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Offline caticind

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Re: Varroa levels in tolerant colonies
« Reply #10 on: January 03, 2012, 11:51:50 am »
Solomon, I'm curious about the managed colony density around your area.  Are your yards isolated?  Are there hobbyists keeping close to you?



I would like to stop treating, and to date have used only mechanical and cultural methods (no miticides whatsoever).  Although I have experienced many fewer losses than I was initially told I would by keepers in the area who are dependent on miticides, I do keep track of varroa related symptoms and I am beginning to see them in my older hives.  That said the hives with the most DWV bees are also the strongest in foraging, cluster and stores in spite of losing those infected foragers. Actually, since one of them had no detectable varroa in August and the other very little, I suspect that they got their current loads not from massive mite replication at home, but by robbing out outside hives with high loads (both are very energetic robbers, judging from the continuing increase in stores I saw after the fall flow had ended).

Perhaps I will see dwindling in the spring.

Here's my concern, though.  If I were relatively isolated, I would be willing to continue with no miticides and lose the hives I lose, in hopes of either selecting for tolerant bees OR finding that I can split quickly enough to keep up with losses (I don't aim to get any bigger than sideline status).

But I'm in a town with quite a few other beekeepers.  I know of at least 3 others within a mile of me.  Many are periodic hobbyists who keep 2-3 hives, regularly lose them, and replace often with packages.  I'm sure that is where many of the drones in my local DCAs come from.  I am not equipped to do nor much interested in instrumental insemination, so even if I selected hard for resistant bees, the odds are the open matings will dilute any successful genetics, making it impossible for colonies to retain resistance over multiple queen generations.  

If that's the case, I'm going to face a choice.  If I cannot sustain my colony numbers without miticides in this environment, do I pack it in?  Choose to knock mites down with an organic acid every other year?
The bees would be no help; they would tumble over each other like golden babies and thrum wordlessly on the subjects of queens and sex and pollen-gluey feet. -Palimpsest

Offline Solomon Parker

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Re: Varroa levels in tolerant colonies
« Reply #11 on: January 06, 2012, 10:01:31 pm »
There are few but not many.  There are also some bee trees around.  I know of two and I keep collecting very small swarms from what I'm assume are small tree hollow colonies.
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Offline specialkayme

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Re: Varroa levels in tolerant colonies
« Reply #12 on: January 06, 2012, 10:46:16 pm »
but much lower than the "treatment" threshold for Fall in the South that my reference books suggest indicates a serious threat to survival.

What reference book?

Offline specialkayme

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Re: Varroa levels in tolerant colonies
« Reply #13 on: January 06, 2012, 10:49:22 pm »
Many are periodic hobbyists who keep 2-3 hives, regularly lose them, and replace often with packages.  I'm sure that is where many of the drones in my local DCAs come from.

You could always select your best hives and breed from half of those. The other half turn into "drone factories," giving them two frames of drone brood per box. Eventually, your drones will change the genetics of your neighbors hives, which would in turn make your DCAs better off for you.

That's not to say the DCAs would have drones from treatment free hives, but when you arn't a huge operation or working on an island, there is only so much you can do.

Offline Solomon Parker

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Re: Varroa levels in tolerant colonies
« Reply #14 on: January 06, 2012, 11:28:04 pm »
I'm trying to expand to new yards, focusing on placing colonies a few miles away in any direction to saturate my area.  Then I do my breeding at home.  Still many colonies needed to achieve saturation.  Even then, there will still be feral hives around, as well as some hobbyists I'm sure.
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Offline caticind

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Re: Varroa levels in tolerant colonies
« Reply #15 on: January 09, 2012, 01:09:11 pm »
but much lower than the "treatment" threshold for Fall in the South that my reference books suggest indicates a serious threat to survival.

What reference book?

The two or three "intro" books I got when I took my first bee school indicated that in the South, a fall count of greater than 150 mites per day required treatment for survival, and drops in excess of 50/day should receive close attention.  I have always been very cautious, and intended to rethink this issue if I saw more than 20/day.  I'm aware that some newer sources, particularly in Europe, consider it a threat of drop exceeds 2/day in the winter, although that number is post-treatment and may not be easily applicable to this situation.

Of course MB above and others have pointed out that there is a lot of doubt that mite fall is a good general indicator of mite load as the fall rate varies with temperature and brood state.

As the thread continues, I'm less interested in mite drops per se and more on the question of how to promote genetic resistance in adverse breeding circumstance, and, if it can't be done, what comes next.
The bees would be no help; they would tumble over each other like golden babies and thrum wordlessly on the subjects of queens and sex and pollen-gluey feet. -Palimpsest

Offline Poppi

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Re: Varroa levels in tolerant colonies
« Reply #16 on: January 09, 2012, 06:34:59 pm »
Seems like this discussion goes on in one form or another all the time.  Just saying...  that varroa is a concern.  Even for those that seem to have a handle on the "no-treatment" avenue and varroa is not a problem for them whether it be small cell or whatever...

I admit to being new but I will say this, after what I have seen with my varroa troubled hive, all the info I have read, the various ways to treat...  there is no guarantee that either method will save a hive...  my experience so far shows me that powdered sugar is useless...   that thymol will knock them back, maybe...   and Oxalic Acid trickle is not effective if you have any brood...   This hive still has a mite count of 75 to 100 a day...  if you only do a mite count once in a great while...  I see where it is of little value.  I have been monitoring the count on this hive at least everyday for 5 of the 7 days a week for the last 3 months.  Before and after treatments...  I have a log of what I have seen and you know what...  the thing I know is this hive has continued to get worse.  Now DFW has shown it's ugly face...  I see 30 to 40 on the ground about every 3 days...  this hive will probably not make it...  so with that in mind I am vaporizing with OA every 7 days for 3 weeks and record that...  might as well do all the learning I can...  can't do Formic because of the temperature restrictions...

When I look in the hive, they seem OK...  but the mite count tells a different story.  So my conclusion thus far is that I should have monitored more often and maybe some of these treatments would have been more effective.  It's obvious that had I not monitored the hive and treated in some fashion, it would be dead or on it's way...   just MHO.



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Offline caticind

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Re: Varroa levels in tolerant colonies
« Reply #17 on: January 09, 2012, 07:21:13 pm »
Many are periodic hobbyists who keep 2-3 hives, regularly lose them, and replace often with packages.  I'm sure that is where many of the drones in my local DCAs come from.

You could always select your best hives and breed from half of those. The other half turn into "drone factories," giving them two frames of drone brood per box. Eventually, your drones will change the genetics of your neighbors hives, which would in turn make your DCAs better off for you.

That's not to say the DCAs would have drones from treatment free hives, but when you arn't a huge operation or working on an island, there is only so much you can do.

Do you mind elaborating on creating "drone factories"?  

I have been thinking about ways to increase saturation in the area, but it's difficult because an urban location means that I have access to fewer places to site hives, and that each site must have fewer hives.  It would be interesting if I could take some early splits (with old queen included) and encourage them to produce larger proportions of drones, increasing saturation at the DCAs when the other halves and later splits send new queens out to mate.  It seems that even a moderate increase in saturation would improve the rate at which daughter colonies retain resistance.

Thoughts?  What method would you use?

I should note that I already use foundationless frames, so I won't see the spike in drone rearing that many folks do by replacing worker foundation with foundationless.

Seems like this discussion goes on in one form or another all the time.  Just saying...  that varroa is a concern.  Even for those that seem to have a handle on the "no-treatment" avenue and varroa is not a problem for them whether it be small cell or whatever...

I don't think that natural-size comb and no miticides is sufficient to solve the problem mechanically, although judging from these hives I do think it helped.  They had lower counts for longer than most in my local club saw with routine treatment.  It's obvious that those who don't treat and start with enough colonies to sustain losses and breed from survivors are selectively breeding for resistance, regardless of what else they do in terms of methods.  The tough part for those of us coping with a constant influx of genes from treated package stock is keeping the resistance even if we can breed it.  

And robbing brings another issue:  bees which succeed in suppressing mite resistance for years may still suffer ill effects if robbers going to mite-crashed hives bring back large numbers of phoretic mites.  Even if the imported mites do not reproduce well, there will still be damage to a generation of pupae due to the increase in disease vectoring.

John, you're presenting some interesting perspective for me, in that I thought my colony was pretty bad, but the symptoms you are describing are worse and count is higher, even though you have been treating and I have not.  

I was worried to see 15-20 newly emerged DWV bees inside the hive on inspection, but the number of DWV dead on the ground each week is no different from last winter, before this colony boomed, absorbed EFB frames from a sick hive like it was nothing, produced 3 splits, and outperformed every other colony in my yards in terms of quick response to dearth conditions.  I can't say that they're good surplus honey producers, but I'm more interested in overall health right now.

It simply will not get cold enough for oxalic here, and though I do not trust sugar dusting for long-term control I may use it repeatedly on these hives to see if I can knock some of the load off while brooding is greatly reduced.

The really interesting thing will be when I can quit my winter speculating and see how these hives far in early spring, whether they crash or are sickly or shake it off.
The bees would be no help; they would tumble over each other like golden babies and thrum wordlessly on the subjects of queens and sex and pollen-gluey feet. -Palimpsest

Offline Poppi

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Re: Varroa levels in tolerant colonies
« Reply #18 on: January 09, 2012, 08:41:27 pm »
caticind,  I'm with you...  I'm doing nothing now but "heroics"...   however, I will be very interested to see if this hive makes it and how well they shake it off...

Like you, I am in a warm climate and OA and the no brood time would be hard to catch even if it did occur.  That's why I'm trying OA vaporization...  So if varroa doesn't kill 'em...  and I don't kill 'em...  I will certainly take a more cautious approach next year to monitoring mite count sooner...    It's very easy for me and only takes a couple of minutes per hive.  I cannot believe that mite counts don't have some bearing on mite populations as long as the counts are performed routinely trends can be seen and not just when someone feels like it...   

The "wrench in the works" for me is when I hear beeks say, "Oh, I never do a mite count."  Or they tell me they never count or treat and their hives have made it 5 years without any issues.  But someone else will tell you with "great authority", take with a grain of salt...  that if you don't treat, the hive will be dead in 2 years...   all this tells me is no one really knows for sure and no one way is best...  so I'm going to do what works for me and I am still learning for sure...  :)

Offline caticind

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Re: Varroa levels in tolerant colonies
« Reply #19 on: January 10, 2012, 11:42:58 am »
Randy Oliver published some interested research on mite drops done in his yards, and had enough colonies to compare the loads to the drops by doing some whole-hive sacrifices and washes.  He also did a literature review.

The consensus was weak, but suggested that drops related well to population during the spring and early summer, but NOT well at all during peak mite (usually September) or during cold weather or broodless periods.
The bees would be no help; they would tumble over each other like golden babies and thrum wordlessly on the subjects of queens and sex and pollen-gluey feet. -Palimpsest

 

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