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From:
Juanse Barros <[log in to unmask]>
Reply To:
Informed Discussion of Beekeeping Issues and Bee Biology <[log in to unmask]>
Date:
Thu, 19 Nov 2009 20:24:13 +0100
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"Randy wrote
me answer ..

"Hi All, and especially Juanse,

Thanks Randy for taking care of myself. Yes Nosema is a serial killer.
Probably with the help of some virus it is a deadly bastard. Probably the
virus is a paralysis virus.

"In the Pacific Northwest, N ceranae follows a seasonal occurrence, peaking
in spring and fall, similar to N apis.

Over here (lat -39) and at La Plata- Argentina Nosema follows a similar
trend. However each ecological area have its own sporulation curve, lower
peak in the plain, higher at the coastal range and very high at the Andes
foothills.

it is wise to describe this sporulation curve for each area to base
managment on this curve. Also based on the long range studies done at
argentina, this peaks shift ahead or forward depending on the
particularities of each season. This season it peaked ahead and with a very
high peak in october.

"However, spore counts mean little, since generally only a small percentage
of the bees in a colony are infected.

Agree, but would said better that what is important is the prevalence
(percentaje of bees infected) rather than the total number of spores on a
given sample.

"Some colonies that show extremely high spore counts from samples of 50 bees
..

We need to use the same metholodoly to have comparable numbers world wide.
 60 bees at the entrance taken at peak flying time. We should all use
Caldwell modified by Fries (1984) method.

"Feeding pollen supplement in fall may be better than fumagillin if spore
counts are low--under 2.7M FROM BEES FROM THE INSIDE OF THE LID.  That means
that the equivalent entrance spore count would be over 5M!

Agree, but, feeding when the counts are high is the worst thing we could do,
since we will be feeding the parasite and not the bees.

Fumagilin is effective at 90%, and spores multiply in 3 days, so it is wise
to give fumagilin when spores counts are under 0.5 M at the entrance (with
Caldwell/Fries method). If bigger than that one need to repeat the
treatment.
*As with varroa we should monitor before and after treatment.*

"Colony spore counts in Calif correlated positively with loss of colony
strength over winter, but the effect was not large.  Colonies with spore
counts of 60M (I will have to check to see if they were inside counts) lost
some strength, but did not crash!

Again, one need to differenciate between colonies with and without viruses.
Also if there is genetic resistance/tolerance. And finally how severe is the
sporulation curve/peak.  So take care with the numbers given.

"Dr Eischen is finding spores on the comb surface, but no one has yet tested
to see if they are the source for transmission of the parasite.  He will be
running that test soon.

I told you Randy. Nceranae is very similar to Napis, but more infective. I
think many of the paper stating that they deal with Napis probably are
dealing with Nceranae. Particularly those after 1980. I think the main and
only differences on the symptoms we can see without a microscope are :
1.- wet and many dropping for Napis in the entrance and roofs, dry and dark
dropping in the frames and top bars for Nceranae
2.- as Bob H says, bees not taking syrup and then drowning in the feeders
(for those who use frame feeders).
3.- some chalkbrood cause of bee depopulation and brood become un atended on
cold spells.


-- 
Juanse Barros J.
APIZUR S.A.
Carrera 695
Gorbea - CHILE
+56-45-271693
08-3613310
http://apiaraucania.blogspot.com/
[log in to unmask]

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