Hi Bob and Everyone,
Bob asked  "Explain what you mean when you say *clean it up*. Do we know what happens to
these lifetime viable spores? Are they placed outside the hive entrance?
stored in honey during the honey flow?"

When given comb with scales a resistant colony may show a few cells of AFB usually starting about 3 weeks after the scale is placed in the broodnest.  The colony over a period of weeks will clean out the AFB cells without any treatment.  After a period of about 2 to 6 weeks you will not find any more active AFB.  If the colony is closely monitored the rest of the season, you will not find any more AFB.  The colony has cleaned it up.  Hygenic bees remove diseased pupa usually before they show any visable symptoms and before they become infectious ( before the spores are formed ) so they actually over time remove the disease spores from the colony.  Most also chew comb with scale down to the midrib before rebuilding or sometimes even just chew it all down and start fresh.  These observations are in colonies where a limited amount of AFB scales in comb have been added to challenge the bees with AFB.  If you add whole frames of AFB it is very likely that the colony will show some active AFB for considerably longer and may be overwhelmed by the great volume of inoculum and succumb to the disease.  This points out the need to continue to inspect the brood combs and remove any visable scale even if you are using highly disease resistant stock.

In summary the bees actually can and do remove the disease spores from the hive over time.

hope this helps

blane



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Blane White
MN Dept of Agriculture
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