# Treatment Free and 2/3 year survival



## DaisyNJ (Aug 3, 2015)

I have come across handful of posts where claims of TF has been questioned if the hive survival is less than 3 years. 
Is there any scientific basis for such questioning ? Is there a thought that Varroa (for example) will only show its ugly head after certain number of years ? 
Or deceases like DMV take certain years to mature and take hold ? 

If any of this is true, are there parameters that can be switched around to reset the clock? Requeen, move the hive into new box, get rid of all old comb and let them build new from scratch etc ?

PS: You can see I am bored while waiting to get started on my first hive


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## Michael Bush (Aug 2, 2002)

Varroa tend to build up over time. The first year a package is installed is not usually when they die from Varroa. It is more likely the second year. I think they throw in the third because they are skeptics, which is fine. I've always been a skeptic.

Yes, you can reset the clock, so to speak. A brood break, splits etc. will set back the Varroa. But I think the object is to get to where it doesn't matter that much and you split because you want to split.


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## fatshark (Jun 17, 2009)

You can model this sort of thing. Randy Oliver (ScientificBeekeeping) has done it and there's a package (software!) called BEEhave that allows you to do this very nicely. Here are three replicate model colonies, each primed with ~20 mites at the start, none treated. Bee numbers (blue) are on the left axis, mite numbers on the right (red).









I've run the model with all the default settings. In this, the colony dies overwinter if bee numbers drop below 4000 - one colony 'dies' in the 4th winter, the other two in the fifth. But look at the mite numbers in the third year (~20,000) and the impact they have on the bee numbers. Even in the second summer mite numbers are unacceptably high. This illustrates the situation that MB describes.

Remember that these colonies were 'primed' with 20 mites each. If you start with more, you lose the colonies faster. This is a model, but it explains what happens without intervention.


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## Fusion_power (Jan 14, 2005)

That model is predicated on certain factors such as bees that are susceptible to varroa. The model will not always fit reality.


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## biggraham610 (Jun 26, 2013)

Fusion_power said:


> That model is predicated on certain factors such as bees that are susceptible to varroa. The model will not always fit reality.


X2. G


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## fatshark (Jun 17, 2009)

Fusion_Power and biggraham610 ... I agree. As I said, it's run at the defaults. But it does illustrate the response that Michael Bush gave to the original poster ... mite levels in an untreated colony build up to high levels over a 2-3 year period. Hence the justification for the 3 year period when questioning TF beekeeping.

I should have made the last line " ... without intervention and with _Varroa_​ susceptible bees".


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## crofter (May 5, 2011)

It would be fairly safe to say, though, that susceptible bees are the representative majority, would it not? According to one retired apiary inspector who runs about a hundred hives in northern ontario, first year survival absolutely untreated is quite common, second year rare and third year very rare. This was for new beekeepers so inexperience could well be a contributor. 

There are several strains of varroa with different potentials for harm (Korean vs Japanese and harboring different strains of DWV), plus different bee breeds with different habits that can greatly affect mite breeding success. I can see different possible scenarios that would result in a variance with the model proposed, yet the three year disclaimer to define TF success may be a fairly reasonable _rule of thumb_ to at least be considered by someone setting out on that path.

Edit: I see Fatshark has posted while I was pecking away.


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## lharder (Mar 21, 2015)

Some people requeen every year. Does this 3rd year survival allow for new queens to be introduced?

I'm asking because I had one hive die of what looks like queen failure. If I requeened every year that hive might be alive. I don't because I want to raise queens that can make it through their second year without failing and beyond if possible. I could have joined it with a nuc this fall, but I'll just repopulated with an overwintered nuc. 

I'm interested in what this mite buildup does to new nucs that are started. Will the success of overwintered nucs derived from tf stock go down with the seasons? A more important question in terms of long term probable success.


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## JRG13 (May 11, 2012)

I don't see the 2-3 year build up here. It's pretty much a single year buildup to crash a hive. There's a few who advocate resetting the clock if you make it that far into year 2 or 3, either by requeening or making a split and simulate swarming the old queen into new equipment and foundation. I don't believe in requeening at this stage of the game yearly as I like to look at longevity, but it's not a bad idea to create a broodbreak late spring or early summer by requeening. I do have some swarm queens and bought queens going into their 4th year despite my neglect in treating early etc... so that is exciting sometimes but their mite resistance is leaving much to be desired.


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