On Sat, 28 Mar 1998, Lloyd Spear wrote:
 
> Carlos Aparicio questioned why a colony would collapse from Varroa when it
> has been existing with populations of Varroa for some time.
> I think we have all experienced this.  I live in a temperate climate and,
> because I raise only comb honey, I keep good records on every colony.  Twice
> in past years I have had my highest producing colony collapse just after the
> supers were pulled.
> Dr. Nick Calderone from Cornell University thinks this is due to such an
> explosion of Varroa that both a high percentage of nurse bees are infected
> and a high percentage of worker larvae are infected.  The net effect is that
> very few worker larvae mature into bees, and the existing worker bees have a
> very short life.  In these conditions, a colony can collapse in just 3 weeks
> as there are no new worker bees to replace those that die.  Dr. Calderone
> thinks that tracheal mites do not cause a sudden collapse, but a longer-term
> degeneration.
> Carlos, this applies to hives in temperate climates where summer/early fall
> collapse is seen.  If bees are raising brood throughout your winter it might
> also apply in that case.
>
 Hi Lloyd and All,
 
 The compexity of the sudden collapse is beyond just a high level of
Varroa. Stress can do it, like moving the bees. That happened to me 3
years ago. 30 hives came down out of thee mountains and I placed them at
my place and the went up 30 days later to move the rest down and was goint
to treat all 90 at the same time. The first 30 were all dead. the ones
that I did not move were ok and took the treatmment with no losses.They
made it through the winter.We have another problem. Varroa is a vector for
3 virues. They have a play in the sudden collapse.When my bees went down,
it was too fast for just weak bees. There are different opinions on what
came first the chicken or the egg.My bet goes with another pathogen
working with Varroa to cause the sudden collapse. I have kept bees for
over 30 years and I had some very strong hives , with great flight for two
weeks after they came out of the mountains. Then nothing.
Thats my nickle.
Best Regards
 Roy