Was watching a video on youtube last night before bed that referenced this article. Thought I would share this with the forum.
John
Maggi, M. D., Damiani, N., Sergio, R. R., María, C. B., Szawarski, N., Mitton, G., … & Eguaras, M. J. (2017). The susceptibility of Varroa destructor against oxalic acid: a study case. Bulletin of Insectology, 70(1), 39-44.
The bottom line for me was that if you treat a hive with oxalic acid (OA) for 8 years, the oxalic seems to remain as effective against the Varroa as it is after the first treatment. In other words, there was no evidence of the development of resistance by Varroa to OA in their study.
My major criticism of the method is that the treatment and control hives were in the same apiary. That means that mites which had been in a treated hive could fairly easily transfer to an untreated hive. As the study was a “snapshot” population study, and not a vertical study (done over time), it may not truly reflect lack of resistance, just that all of the mites in that apiary had the same sensitivity to OA.
Resistance to oxalic is highly unlikely because applied as a vapour it burns the mites’ feet and mouthparts. It’s nigh on impossible to acquire immunity to this sort of physical assault. In addition it is tolerated really well. I have a couple of queens that have been exposed one, to 12 vapes and the other to 15 and both are still going strong.
So many points to like about your post Dee - Happiest to hear about your queens but it’s also quite gratifying to be reminded of the way oxalic acid actually works Studies are of course important, but sometimes I think people lump OA in with miticides.