Hi All

Bob wrote about Diana Cox-Foster, reminding us that comb can be virus-contaminated.

Steve asked: 

> 1. How many years can you safely use brood comb?  It seems 
> like you could have virus infected comb after one season 

and Chris asked: 

> How do they persist on comb? For how long?

Here (http://www.bbka.org.uk/articles/bee_diseases.php) it is stated that Sac Brood Virus becomes non-infective within a few weeks.  Longer than many viruses away from their hosts, but not long enough to for re-infection from equipment vacated in the winter and re-occupied in the subsequent summer.  Of the other picorna viruses more strongly associated with Parastic Mite Syndrome, I know nothing. Does anyone?

Bob mentioned that Diana Cox-Foster's research, suggesting that comb renewal could be important to reduce virus load.  Reading her papers (this one in particular):
http://vir.sgmjournals.org/cgi/content/full/86/8/2281

.. it would seem that Varroa and its saliva does carry some picorna-like viruses and could be a vector, but also the queen lays virus-contaminated eggs and that worker to larva transmission takes place.  Simply renewing comb is unlikely to break the cycle of infection with this and related viruses, and so I doubt that comb renewal could be justified on this issue alone.

One of our regulars wrote this back in 1999:

"Destroying older combs that are still in good shape is another of those
things small-time beekeepers do to make sure that they stay small-time."

Yet comb renewal has become a popular call - does anyone have concrete evidence of a benefit from comb renewal, beyond the possibility of relief from Foulbrood, Nosema and perhaps Chalkbrood?

all the best

Gavin

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