To find out more we went for a visit.
To find out more we went for a visit.
Perhaps I will visit some time too if he will receive me.
Yes I agree with you, 18 tf years is great. It depends on the situation whether you can do the hard bond.
Erik does not treat 50% every year since he treats only those over a threshold. Itīs not the same every year it depends on reinfestation from outside as I understood.
But I canīt see much difference to the results if the queens are shifted, except to loss numbers.
John talked about soft bond in his speaking in Austria as an approach if too high loss is the fear. And Iīm convinced the expression of resistance shifts all the time depending on many circumstances, thatīs why selection never stops.
Did not John has mating yards isolated just like you? Itīs easy to obtain good traits then.
But not we. As you said, we canīt control this so we have to select and manage in different ways.
We hobbyists are not able to afford high cost queens like yours or John`s so we are very happy to get queens from resitance breeding projects which support us by selling queens for a "normal" price.
The rest is up to us, propagating them and selecting as much as we can, making the resistant rising a local quest.
Last edited by 1102009; 10-29-2018 at 12:50 AM.
Since 1985 there had been breeding work done by Wolfgang Ritter in Tunisia with Intermissa black bees. This pre-selected stock was then sent to Kefuss in Toulouse France 1993. John explained that because beekeepers in Tunisia had too little money they were not able to buy stuff to treat their colonies. Ritter realized this opportunity and started selecting. Same story in Siberia, with Primorski and Rinderer…
In the end of ABJ article there is a reference to Apidologie 21:368-370, by Ritter W (1990), I cannot find it for some reason. * Name of the study is supposed to be “Development of the varroa mite populations in treated and untreated colonies in Tunisia.”
By 1996 most of the original queens had superseded. In 1999 they started new study with the offspring of the best queens.
Because both the Intermissa and Carniolan control were originally black, they could confirm the results of free mating. The superseded hives got more yellow colouring. They write: “After 1996 all the remaining colonies probably became genetically similar.”
Interesting for the IPM enthusiasts are their remarks in the discussion part of the study:
“…This suggests that, as infection persisted, colonies reacted more strongly to the presence of varroa. The positive slopes of the regression lines indicate a tendency for both races to eliminate a higher percent of varroa as the infestation level increased. This high elimination may be a simple population threshold reaction. Care must be taken when using high varroa fall as an indicator of susceptibility. Under certain conditions on the contrary, high varroa fall may simply represent lower receptivity… This means that by itself varroa fall is not a valid indicator of susceptibility.”
They gave a definition to receptivity in the introduction: Receptivity is the possibility of an animal to permit the presence of a parasite and the normal development of its life cycle.
In the late part of the study, from year 2000 to 2002, when the colonies had “become genetically similar” the infestation level (varroa on bees) medians varied between 1,72% (April 2002) and 5,39% (October 2001).
Talking to John it seems to me now, that what happened in his beekeeping was duplicate of this study. The only difference is that he managed to maintain viable colonies for a much longer period. In the study free mating did not affect results in the beginning. But then they write: “The accelerated drop in colony numbers after 1999 (after 6 years of tf) might be due in part to the dilution effects of earlier natural mating with susceptible drones.”
Last edited by Juhani Lunden; 10-29-2018 at 05:36 AM.
Thanks for posting about the Kefuss visit. I hope someone continues with his bees. I would really like to see more up to date data about his operation.
There must be a different philosophy between father and son. If he's breeding queens from the TF breeders, but all other hives are treated, basically that is a recipe to lose the TF bees they will get drowned out.
I see the bees look pretty yellow, but the foundation TF stock was black. Wonder if they could go back to their roots and import a new batch of foundation stock.
"Every viewpoint, is a view from a point." - Solomon Parker