A way to combat CBPV?

[jenkinsbrynmair]

OK, some have asked me to set out the theory of the no floor method of dealing with CBPV.
Can I just state that this is not 'my' idea, just something that came up in discussion between a few RBI's and bee farmers when we were being put through the hoops for our DASH accreditation a few weeks ago.
I'm not going to go into great detail about the disease (Cos I'm not that erudite nor am I a scientist) but basically Chronic bee paralysis virus is an unclassified bipartite RNA virus transmitted through two main mechanisms. The first mechanism is viral transmission through bee faeces, which remains on the hive floor and can be picked up on the furry legs of other bees and ingested orally. The second mechanism is through close contact between bees in the hive. Worker bees are the most susceptible to infection, since they travel the hive most frequently. The infection may spread between hives as a result of indirect contact or direct contact between honey bee.
No 'cure' has been found for CBPV yet, no magic elixir or super drug.
One thing you should not do is what some bee farmers tried in desperation and ignorance of all the factors when it first flared up was to do what was labelled a 'vertical shook swarm' which was done by caging the queen, taking the colony away from the hive stand then shaking the workers off by throwing them in the air in the belief that all the infected bees would just fall to the floor and the healthy bees would return to the stand and a new clean hive with fresh frames and the queen.
This does not work as one of the symptoms of the virus is disorientation and loss of homing instinct, so all you got was a load of confused bees begging their way into any old hive and spreading the virus to other colonies.
OK. back to what you can do.
The virus seems to flare up when bees are overcrowded or under stress, so the first thing to do is try and give them more room so they are not so closely packed, thus reducing contact (Hmm, that sounds familiar) between individual bees.
Now this next method is something that it being unofficially trialled and monitored at the moment and it has given successful results in almost all cases.
CBPV is spread by contact from bees walking through infected bee faeces on the hive floor, and especially mandibular contact - the higher risk of this is when the mortuary bees have to carry virus infected dead bees out of the hive (and at its height there are a lot of corpses)
So let's remove the floor - this way there is no contact with infected faeces and no piles of corpses waiting to be carried out.
When all this was being explained to us the first thing we were told is 'forget your 'pallet hive stands folks' so

• You need a 'proper' open railed hive stand about 12 to 18" high so any corpses fall well outside what the bees consider their 'indoors'
• get/make an eke, doesn't really matter how deep, you could even use an empty shallow
• you don't really need a proper entrance at the front of the hive, the hole in the floor will suffice, do away with any landing board [My contribution]
• Put the eke on the stand instead of a hive floor
• Take the brood box off its floor and put it on the eke - job done

Obviously there are other considerations, like the risk of robbing etc. with a strong(ish) colony, this shouldn't be an issue so it's up to the beekeeper to monitor and to consider the time of the year when it is done. Feedback so far was that even when there were wasps around, the bees coped.
Same goes for the timeframe, suck it and see - monitor and watch for improvement
as for other secure considerations, I'm sure peole are imaginative enough to work something out, just remember - you need a decent height below the brood frames so that the corpses fall well without what the bees consider the hive, I don't think enclosing the whole thing off down to the floor level is a particularly good idea as the bees may just consider tidying it up.
Collecting the dead bees and disposing them away from the colony is a good idea. the simplest and best dea I think would just be a sheet of polythene or an old fertilizer bag weighed down under the hive whick you can then just gather up and take away to shake the dead bees out onto your compost heap or whatever.

 

[Erichalfbee]

"Same goes for the timeframe, suck it and see - monitor and watch for improvement"

Bryan's colony took six weeks before they were up and running with a filling super

 

[LeaBees]

“I don't think enclosing the whole thing off down to the floor level is a particularly good idea as the bees may just consider tidying it up”

I was going to ask on this as I have enclosed all the way down and found bees boiling out the bottom when tried to check deadfall. Could have been not enough space below Bbox so I have added an empty BBox to elevate further. With that height (stand. bbox and small eke) hopefully enough. Will be removing surrounds (except front to avoid use as entrance) tomorrow morning unless think otherwise.
Thanks.

 

[Newbeeneil]

I can see the advantages in this method to combat cbpv but would the bees not drawn the combs down? Would a slotted rack floor be a neater solution?

 

[Erichalfbee]

I can see the advantages in this method to combat cbpv but would the bees not drawn the combs down? Would a slotted rack floor be a neater solution?

The bees are sick. Would they draw any comb? Especially down to the cold ground?

 

[jenkinsbrynmair]

you are still giving them a floor - nurse bees will then still try and remove the corpses - the whole point is to give them a gaping void so they see that as the exit, that's why I am a bit dubious about creating an entrance in the front of the eke - a bit like landing boards on healthy hives - they're there to satisfy the beekeeper not the bees

 

[LeaBees]

you are still giving them a floor - nurse bees will then still try and remove the corpses - the whole point is to give them a gaping void so they see that as the exit, that's why I am a bit dubious about creating an entrance in the front of the eke - a bit like landing boards on healthy hives - they're there to satisfy the beekeeper not the bees

Would that not lead them to want to clear deadfall beneath the hive as they are constantly passing it by? Or is the 12-18" sufficient that they may ignore?
I'm undergoing this method at the moment and have a 2cm hole in the eke as well as an empty brood beneath the nest. Activity from both the eke entrance and beneath. Still early days at the moment but still seeing bees trying to clear.

 

[jenkinsbrynmair]

Would that not lead them to want to clear deadfall beneath the hive as they are constantly passing it by? Or is the 12-18" sufficient that they may ignore?
I'm undergoing this method at the moment and have a 2cm hole in the eke as well as an empty brood beneath the nest. Activity from both the eke entrance and beneath. Still early days at the moment but still seeing bees trying to clear.

I wouldn't know - I'm just passing on information on a system that has worked for many others.
I think again we are seeing the usual habit of overthinking everything
Put the brood box on an eke, with no floor and on a tall stand, end of. Any other embelishments or fiddling around may skew the whole thing, then again someone may find the perfect revision.
Whatever it is, the insistence of having some kind of floor is defeating the whole object. IMHO adding an entrance when the whole bottom is open to the elements is just a bit daft.

 

[cwinte]

So how does OMF floor work out? I have the open mesh floor on a stand with rails about 20" over a large tile placed on the soil...
I do not see many bees dead inside on the OMF, 99% + are outside the front.

 

[Ian123]

So how does OMF floor work out? I have the open mesh floor on a stand with rails about 20" over a large tile placed on the soil...
I do not see many bees dead inside on the OMF, 99% + are outside the front.

There’s no mesh the floor is completely open.

 

[jenkinsbrynmair]

So how does OMF floor work out?

There isn't one - or any floor at all, the dead bees fall straight out, and because of the distance between the bottom of the frames and the floor, they consider them to be 'outside' and therefore don't need to carry them anywhere, the whole point of this is to stop bees having any mandibularar contact with dead, infected bees and picking up the virus themselves.

I do not see many bees dead inside on the OMF, 99% + are outside the front.

Exactly - the undertaker bees have had to pick up the dead and dump them outside the hive, and in doing so, get iunfected themselves.

 

[Apiarist]

...basically Chronic bee paralysis virus is an unclassified bipartite RNA virus transmitted through two main mechanisms. The first mechanism is viral transmission through bee faeces, which remains on the hive floor and can be picked up on the furry legs of other bees and ingested orally. The second mechanism is through close contact between bees in the hive....

hi Jenkins

do you have the reference(s) from where this information came from.

(I'm paraphrasing from memory here) When I read Bailey's assessment of CBPV, etc. I found it sufficient to not do that much further research into the subject (maybe now with hindsight this may have been a bit lazy). Is it therefore my understanding that you (the person that relayed this info. to you) is dismissing / refuting Baileys research findings? In that, ONLY bees WITH Acarapis woodi mite infestation of the T2 Trachea, exhibit symptoms of CBPV... the implication being that; get rid of the mite (most varroa treatments left in the hive will work) and you effectively get rid of CBPV, bees infected with the virus only live a short while.

 

[Erichalfbee]

hi Jenkins

do you have the reference(s) from where this information came from.

Her's one
https://www.nature.com/articles/s41467-020-15919-0

 

[jenkinsbrynmair]

(I'm paraphrasing from memory here) When I read Bailey's assessment of CBPV, etc. I found it sufficient to not do that much further research into the subject (maybe now with hindsight this may have been a bit lazy).

I think so - things have moved in quite a bit since he wrote on the subject

 

[Erichalfbee]

I think so - things have moved in quite a bit since he wrote on the subject

I looked for that and could find only something dated 1963?
I have asked David Evans

 

[jenkinsbrynmair]

I looked for that and could find only something dated 1963?

yep

 

[Jules59]

I wish I had tried the remove floor approach.
In April I had a WBC colony on double brood (16 frames of brood)+ 2 supers. They went from looking great to piles of dead bees in a couple of weeks. I tried a variety of solutions as advised by club and BI; re-hiving into a clean hive , regularly clearing the hive floor, shake out - all failed. By June there were still plenty of bees (Q had kept up with the huge losses) but there was little in the way of stores compared to my other hives. Clearly the foragers were dying off early. Eventually they went queenless (? why) and I decided to exterminate them as they seemed doomed (unable to build up stores) and were a risk to my other hives in my garden- I dont have an "isolation" apiary only the far side of the garden.
Maybe an open floor would have helped - without trying I dont know. But next time I will.

 

[Erichalfbee]

I wish I had tried the remove floor approach.
In April I had a WBC colony on double brood (16 frames of brood)+ 2 supers. They went from looking great to piles of dead bees in a couple of weeks. I tried a variety of solutions as advised by club and BI; re-hiving into a clean hive , regularly clearing the hive floor, shake out - all failed. By June there were still plenty of bees (Q had kept up with the huge losses) but there was little in the way of stores compared to my other hives. Clearly the foragers were dying off early. Eventually they went queenless (? why) and I decided to exterminate them as they seemed doomed (unable to build up stores) and were a risk to my other hives in my garden- I dont have an "isolation" apiary only the far side of the garden.
Maybe an open floor would have helped - without trying I dont know. But next time I will.

I too have killed bees knowing no better. It’s a heartbreaking thing to do. At least this gives them a chance

 

[cwinte]

I'm still unsure if my colonies have/had CBPV, BSI said yes but David Evans had his doubts given the details of the 1 year of apiary history. Whatever it is I suspect the remedies will be similar: shook swarm (with its risks) and/or the long drop floor.
I'm surprised there seems to be little research on if/how much these viruses transmit from kit/frames etc. lack of evidence... but makes sense to me that kit to bee is less important than b-b.
I will try the long drop asap and report back on findings re front area, drop zone overall death rate changes.
I'll probably also harvest supers (they have added 15kg in the last month) and maybe create more space too to reduce contact density - although that would detract from direct evidence of the long drop/floorless effectivity... it's my last colony!
I'll hold off on any form of emptying out, though I have in mind an arrangement that should minimise loss of bees to outside the apiary by using a bait hive near the drop zone based around the brood shallow from the same hive. I imagine I could quite easily repeat this 4 or 5 days later if it seemed to help. Since I only have one hive left I have no worries of local spread.

 

[Erichalfbee]

I looked for that and could find only something dated 1963?
I have asked David Evans

David Evans says there is no link between tracheal mite and CBPV