, doesn't the resistance not still persist and build with each years use?
Phillip
Resistance will only be maintained if the same miticide is constantly used that it has become resistant to. Resistance is quickly lost if the "resistant" agent is not present as it's energetically and genetically expensive for any organism to maintain resistance to something that is not present in it's environment and ergo there is no requirement to do so. Which is why changes are important. Three years is the mantra, but it could easily be 4 or 5. But changing every three years seems to work okay.
Still not had anyone clarify what the threshhold level for mites is before treatment is needed?
Threshold: it's changed over the years. And by "it" I mean the consensus among American academic voices (because that's what I have access too). When I took bee school, consensus was 10/300. A few years later it went down to 6/300. Now, when I hear this conversation, folks are saying 2 or 3/300 is time to medicate.
It was explained to me as "economic threshold" : when the mite load on the bees is significant enough to be deleterious to honey production equivalent (economically) to the expense (supplies and labor) of treatment. This was back before "we" understood the second order effects of mite infestation, namely vectored disease.
So that explains why the threshold (which is a consensus figure among practitioners/ academics) has gone down, because "we" account the second order effects of disease to mite infestation, and so economic threshold is lower because infestation is accounted more expensive. Also because OA specifically is cheap, and so lower costs of treatment also bring the threshold down.
Man I hope that made sense to you, it makes sense to me but I have ... issues. ;)
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