http://www.mamamoer.nl/ddb/blz/rapportprimoengels2002.pdf
Here is 23 pages explanation from primorsky/Russian bee during years 2001 -2002.
They compared Russian with Carniolan hives ( 11 both)
There they say that the biggest explanation to mite resistant with Russian is that bees pull varroa contaminated pupae out. It leads in dramatic diminishing of colony.
Carniolans gathered 28% more honey.
I couldn't get the post to display on my laptop. But the idea sounds interesting. I've been toying with the idea of getting some russian bees because they are suppose to be more winter hardy. Maybe I'll try Carniolians as well and compare.
Unlike you honey production is a extra side beneift--I'm more interested in developing good hive management practices. How to get the most out of the bees by giving the type of environment they need.
I've never had more than 10 hives at any one time so my experiments have been on small time formats.
Interesting. I have carnolians next to Russians. The carnolians are well into the supers - the Russians are not. The winter in our state was catastrophic to Italian hives. Many pros lost up to 60% of their yards. My Carnolians wintered well as did many who use them. The state inspector is recommending Russians. :?
Quote from: fcderosaThe winter in our state was catastrophic to Italian hives.
It depends what is origin of Italian stock. Stock must have instinct to notice that winter is coming. If that features is selected out, they surely will die.