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during our summer dearth here in northeast alabama we can see a dearth induced brood break lasting for a couple of months. the reduction in population is helpful in terms of not so many mouths to feed and conservation of stores.
 

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Open discussion, all comments are welcome. I jumped in later than you did so if anyone is intruding, it is me.
 

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during our summer dearth here in northeast alabama we can see a dearth induced brood break lasting for a couple of months. the reduction in population is helpful in terms of not so many mouths to feed and conservation of stores.
In your area with the summer dearth it sounds like the forced brood break could be a plus. Not so in our short season with a gradual flow and no fall flow.

In conversation with WWW from central Ohio; he planned the break to reduce populations during the dearth then planned to requeen in time for fall rebuild of bees but found abysmal queen mating results. Cardinal birds, dragonflys and robbing. Local conditions might put the lie to what is a good idea somewhere else.
 

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In the equipment forum,we were having a similar discussion on brood interruption and grozzie brought up this study.

Evaluating the Efficacy of Oxalic Acid Vaporization and
Brood Interruption in Controlling the Honey Bee Pest
Varroa destructor (Acari: Varroidae)
Cameron*J. Jack,
1,3, Edzard van*Santen,
2
and James*D. Ellis1

I spoke with Jamie last Sat about getting a copy and he said to send him an email request.I did and had a pdf by noon Mon.

mailto:[email protected]

Mortality rates for brood interuption were very high.
A quote:
"Florida has
prolonged warm seasons and very mild winters; therefore, we hy-
pothesized that brood interruption would be a safe treatment even
during the early fall. However, based on the high level of colony
mortality, we recommend that brood interruption only be attempted
during the summer months or possibly not at*all."


In the accompanying graphs,all treatments,including controls showed a pretty good decline in the numbers of bees and brood during the roughly 2 mo period of the study.This suggests to me that even though Fla has warm temps in the fall,the decreasing forage results in decreased brood rearing as the bees prepare for the Fla version of winter.A brood break at this time turns out to be disastrous.
 

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In your area with the summer dearth it sounds like the forced brood break could be a plus.
my take is that the dearth conditions force the brood break so the beekeeper doesn't have to. i think this weather pattern tends to drive local selection toward favoring a strain that down modulates brood rearing during times of dearth, and one of the side benefits of this is putting a dent in mite breeding as well. should decreased mite breeding be combined with the trait of grooming and mauling it could be that the colonies are able to reduce the mite infestation during the dearth and prior to the late season brooding up of the wintering bees. i hope to have enough time some day to undertake some careful observations to rule in or out such a paradigm.
 

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my take is that the dearth conditions force the brood break so the beekeeper doesn't have to.
This is what I see here during the July/August dearth. I don't know the exact conditions that trigger the restart of egg laying, but I am guessing some sort of combination of day length and a rain event. Or the amount of stores or.......

Alex

Edit; I should say when I refer to a brood break, I am talking about an absence of sealed brood, not a total lack of eggs or larvae.
 

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In the equipment forum,we were having a similar discussion on brood interruption and grozzie brought up this study.
The part of that study that really stood out to me was the table of survival rates within each group. They used 10 colonies per group. Positive control got apivar. Negative control got nothing, just left alone. Oxalic acid two ways, first a single treatment, second 3 treatments at week spacing. Then brood interruption, and then brood interruption combined with each form of oxalic acid treatment. The numbers were not insignificant and all the combinations and permutations were run. Survival results

Code:
Treatment   Survival
=====================
Neg Control:  0.7
OA-1:         0.5
OA-3:         0.7
BI:           0.1
BI-OA-1:      0.4
BI-OA-3:      0.6
Amitraz:      0.999 *

* To calculate odds rations, survival cannot equal 1.  Thus, 100% survival is presented as 0.999.
I look at those numbers, Negative control and the two forms of OA have similar survival ratios, but the two that stand out completely from the rest, only 10 percent survival on the group that got just a brood interruption, and 100% on the group that got Apivar. The other thing that stands out to me, the 'Do Nothing' group fared as well or better than all the rest of the test cases, and FAR better than those that got just brood interruption.

If one reads the study, colonies were made equal before things started, but once started, there was no transfer of frames etc between colonies.

There is one thing I do take issue with on the way the study came to these numbers, but it's not the fault of the investigators. Label for Oxalic Acid in the USA apparently says 1g per brood box. Label here in Canada says 2g per colony. I cant help but wonder if the poor showing for OA is due to under dosage. But no matter how you twist the data, the groups that had a brood interruption fared worse than those who did not get a brood interruption, but all else the same.

My ultimate takeaway from this study tho is irrelavent of the OA methods or applications. The 'do nothing' group had 70% survival, the group getting just a brood interruption had 10% survival.

I stand by my statements earlier. A forced brood break in September is a great way to kill colonies. The study by Dr Ellis at al confirms this.

People can wish and hope and postulate about things in ways that sound great forever, but in the engineering world there is a quote I am fond of. 'One measured test result is worth a thousand expert opinions'. This study provides a measured test result in a controlled environment, and the results are quite definitive. Brood interruption does not control mites, and it does kill colonies.
 

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In my area, a 24 day, forced brood break in September would mean the delay to the start of long lived Winter bee production. If the Queen was laying a mere 500 eggs per day that would be the loss of 12K Winter bees.
I can see how that could spell doom for a colony.

Alex
 

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A brood break itself is not what makes the Varroa population decline (they can survive longer than 2 months as phoretic mites), it usually the treatment following it to kill the mites that are then mostly phoretic.
In a treatment free approach, a different method is called "brood trapping" that DOES greatly reduce mite population (method explained in details by R. Büchler in his presentation at the 2019 UK Honey Convention available online), where you isolate the queen on a comb where she can still lay (but she cannot move to another comb) when the comb is full of eggs you take it away (replacing it with another empty comb for the queen to keep laying) and you place it in the brood nest for nurse bees to take care of it. 9 days later (fully capped) you take it away and freeze it. You repeat that comb trapping for 3 cycles (27-28 days) and up to 95% of mites can be destroyed. It can also be combined with a treatment at the end for the remaining phoretic mites. This method has to be used about a month before the usual honey collecting time, so that you don't affect the winter bee population.
 

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A brood break itself is not what makes the Varroa population decline (they can survive longer than 2 months as phoretic mites), it usually the treatment following it to kill the mites that are then mostly phoretic.
that's not what the science shows as Dr Büchler notes the Italians have done a LOT of work on it. many many studys, and they show a dramatic effect, far more impact then even a few brood on OAVs
here is a 26 day caging cageing.jpg
https://www.apimondia.com/en/compon...UWhxjxLrLtrL6mtB02YHpYuh7vlBa2WE0lxTg9w8DtoAy

but just going by your example.... if a mite lives 60 days every day of a brood break means a 1/60th reduction in the mite population as mites are dieing and not being replaced so at a spit ball 30 days of a brood break leting a hive re queen its self, all the mites 30 days and older when it started will be dead and didn't get to reproduce

the main issue is on a commercial scale its a PITA and a lot of labor, Elizabeth Walsh with Texas AM has been working on a Refrigerated storage project to test its viability to create a forced brood break on a large scale as part of an IPM program
 

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I don't understand your statement (and I think we totally agree on the results), because the graph you show is exactly telling that Queen caging + Oxalic treatment kills double the amount of mites compared to queen caging alone... (what I have said in previous post).
 

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"A brood break itself is not what makes the Varroa population decline (they can survive longer than 2 months as phoretic mites), it usually the treatment following it to kill the mites that are then mostly phoretic."

In his presentations, Büchler clearly states that during the brood interruption 1% to 2% of the mites die per day which is around 40% to 50% of the total mites before a comb trapping or oxalic treatment.
 

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Discussion Starter #34
Keep in mind that I am in zone 9a. Bees are flying throughout the winter.
 

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My bees fly year round also. My opinion is that it is would be ****ed hard to find all the queens to cage.

Easier would be to have a drone comb at the edge of the brood box which could be periodically removed and destroyed (fed to the chickens?) This would work really well if you, unlike myself, used plastic foundation so the bees can't raise drones everywhere. To get the drones just insert a frame with no foundation at side of the brood nest--position 2 out of 10 frames.
Guaranteed that they will build drone comb in that frame. I know MB, if he's around, will object.
 

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Discussion Starter #36
My bees fly year round also. My opinion is that it is would be ****ed hard to find all the queens to cage.

Easier would be to have a drone comb at the edge of the brood box which could be periodically removed and destroyed (fed to the chickens?) This would work really well if you, unlike myself, used plastic foundation so the bees can't raise drones everywhere. To get the drones just insert a frame with no foundation at side of the brood nest--position 2 out of 10 frames.
Guaranteed that they will build drone comb in that frame. I know MB, if he's around, will object.
Looks like we have similar situations. I stopped buying foundation a couple of years ago, but it isn't too hard to cut out drone comb. I may give that a try this year. Yes, finding all the queens is an issue. I'm sure the chickens would love drone comb. Although, I have wondered what it does to them to be eating wax. I have one smartie that tried to follow us around so she could get the bees falling off the lids. She loved it when hubby put a lid down, bees facing toward her. Had to reposition that quickly. What do you use for mite control?
 

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"A brood break itself is not what makes the Varroa population decline (they can survive longer than 2 months as phoretic mites), it usually the treatment following it to kill the mites that are then mostly phoretic."

In his presentations, Büchler clearly states that during the brood interruption 1% to 2% of the mites die per day which is around 40% to 50% of the total mites before a comb trapping or oxalic treatment.
But how many bees are dying each day? The brood break obviously ceases reproduction of not only the mite but also the bee. Have you reduced the mite-to-bee ratio?

And when your queen starts back laying, your mites are going to out-breed her 2 to 1.

The UF study (Ellis, Jack, Santen) is troubling. I have a lot of nits to pick with it (24d break, Season, etc.), but you cannot escape the fact that the control group (no brood break) out-performed all groups with brood breaks, even those that received OAV during the brood breaks. You can't ignore that.

How healthy is it to force all of your mites and all of those viruses, en masse, onto your adult bees within a 2 week period? I think we may have been overlooking the negative impacts of forcing these events on our bees.

As always, we will wait on the research to tell us more. Proceed with caution.
 

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well, I find that study a bit convoluted and I draw a different conculdstion then you do
https://academic.oup.com/jee/advance-article/doi/10.1093/jee/toz358/5697464
"In general, colonies with caged queens had statistically lower mite fall levels than colonies with uncaged queens starting from day 24 (P = 0.032) and continuing throughout the rest of the experiment (days 31, 35, and 62—P < 0.001). However, we did not observe any significant differences in mite fall during the OA treatment periods (days 8, 16, and 24) between colonies with caged and uncaged queens that were treated one"

they did not see a difference in mite drops between broodless and brood on hives... this suggests there is a huge problem with the OA's effectiveness in this experiment
a conculstion they also reached
" colonies receiving three applications of OA still had high mortality rates and colony strengths similar to those of untreated colonies. Our inability to control Varroa effectively regardless of OA treatment suggests that the current labeled dose of 1 g per brood chamber was ineffective, at least under the conditions we maintained in our study."
 

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Take the OA out of the equation.

The control colonies with no brood break and no OA had a .7 survival rate.

The colonies with a brood break and no OA had a .1 survival rate.

I do not think this part is convoluted at all. The only variable is that 10 colonies had a brood break and 10 did not.

My only question is whether you would get the same result in the spring vs. fall.

My takeaways from the Ellis study:

1. If you are going to make them broodless, you **** well better kill the mites while they are broodless. Otherwise, you probably just stressed your bees for no net benefit.

2. OA treatments using 1g per brood box will not give you a sufficient mite kill -- even when broodless.
 

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You can't ignore that.

Many will because they dont want to look at the facts, they just want to cherry pick out any pieces that may re-inforce a belief system, and trash anything that doesn't do that. they will be quite happy to ignore the 10 percent survival of the bees managed with just brood breaks, and find lots of fault with the improved 70% survival of the negative control 'do nothing' colonies in comparison. And they will give absolutely no credence to the little detail of the positive control colony set, 100% survival given apivar strips.

The data doesn't fit a pre-concieved belief system, so, they will just twist it and re-intepret until they can make it fit.

Personally, I've read, and re-read that study. I've been using Oxalic and Formic for years, and my overall results have been similar to results from this study. We expect 70% survival from our treated colonies, it's about the average year over year. 10% survival for untreated, seen that. What catches my eye more than anything else from that study, 100% survival of the colonies that got apivar.....
 
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