Onward. Been researching any new info online re OA and mite resistance.
It seems that the jury is still out on using OA solely for mite control through the extent of our beekeeping years, saying that we should be alternating treatments in spring and fall each year. However, it is leaning more to the positive side of the mites Not getting resistant to OA.
Randy Oliver, Scientific Beekeeping ~
https://scientificbeekeeping.com/varroa-management/varroa-ipm-strategies/Development Of Resistant Mites
I’m often asked the question; won’t varroa develop some degree of resistance to oxalic acid? The biological answer is that one would certainly expect so if oxalic acid were applied over many generations without rotation of treatments. But that does not appear to be the case. In a recent study, Dr. Matías Maggi [[15]] compared the susceptibility to oxalic acid between two Argentinian mite populations:
1. One that had been exposed to 64 consecutive treatments of oxalic acid dribble (8 times a year for 8 years) as the sole mite treatment, vs.
2. A control population that had never been exposed to beekeeper-applied organic acids (the beekeeper had used coumaphos, flumethrin, or amitraz in a rotation scheme).
He found that the oxalic-exposed mite population didn’t exhibit any sign of resistance—in fact, it surprisingly appeared to actually be more susceptible to oxalic than the oxalic-naïve population. This is good news, since it suggests that whatever the mode of action of oxalic acid is against mites, that it’s not easy for them to develop resistance.
