Re: How long does EFB survive?
1. Freezing has no effect on the spores of American Foul Brood.
2. European Foul Brood is non-spore forming, but the bacteria can last for some time in larvae that died from the disease. How long I don't know, but EFB is usually easy for a colony to clean up, so I would not think the bacteria last more than a week or two. The usual method of making a colony queenless for 10 days works well as it gives the bees time to clean up the dead larvae, if the bacteria persisted very long the method would fail because of reinfection. I don't know if the cold would have an additional effect on the bacteria.
37 years - 25 colonies - IPM disciple - naturally skeptic