questions and theories on how OA kills mites
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  1. #1
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    Mar 2013
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    Default questions and theories on how OA kills mites

    Things are quiet around here so I thought it was a good time for a new theory. From everything I have read, nobody is really sure of the way oxalic acid works to kill mites. It is assumed that it burns or damages the feet of the mites when the crystals pierce them. It has also been stated that the bees do not notice the mites because the mite give off an odor that masks their presence to the bees. I have my own theory and would like to hear your thoughts on it. The one thing I have really noticed when doing oxalic acid vaporization is that the bees in the hive are absolutely covered in the little crystals afterwards. When doing oxalic acid dribble, the bees again are covered with the liquid solution. The only way the crystals or the liquid can be removed from the bees is if the bees begin grooming each other. Is it possible that the presence of the oxalic acid starts a cycle of grooming in the hive and in the process the mites get groomed off the bees? Could the oxalic acid react with the scent on the mites so they now show up to the bees as an intruder?

    I have not seen any studies that show proof that OA damages the mites in any way. That in itself makes me wonder what is really happening. We have also seen that the act of putting powdered sugar in beehives will also cause mite drop. Perhaps OA and powdered sugar it work in the same manner.

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  3. #2
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    Apr 2017
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    Aylett, Virginia
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    Default Re: questions and theories on how OA kills mites

    I like that you are thinking outside of the (bee) box. The problem I see is that in grooming, most of the mites survive and are killed when they drop onto the oil coated sticky board. With OAV, the mites that drop are already dead. I doubt that the bees killed them. I do wonder if OAV and OAD work in the same way though. If they do, it has to be the acid itself, not the micro crystals, that does the damage. I have assumed the OA dissolves the feet and the mite bleeds out.
    Thankfully, the bees are smarter than I am. They are doing well, in spite of my efforts to help them.

  4. #3
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    Mar 2013
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    Default Re: questions and theories on how OA kills mites

    How do you know they are dead before they drop? When I do OAV, I often see a few of the mites still kicking but most are dead. But I have no idea when they died or how.

  5. #4
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    Feb 2006
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    Massillon, Ohio
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    Default Re: questions and theories on how OA kills mites

    If it is simply an action of grooming, why would OAV have such a greater efficacy than powdered sugar?

    I lean towards the theory that the acid itself impacts the mites in some way, causing a rapid or sometimes slow demise. With all the curious scientists out there I find it incredible that after all these years the answer remains an enigma.
    To everything there is a season....

  6. #5
    Join Date
    Dec 2011
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    Lottsburg, Virginia USA
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    Default Re: questions and theories on how OA kills mites

    One of the commercial beekeepers Charles Linder did a series of tests with live mites by putting OA crystals on their feet as this was the way most folks thought the Oa gained entry into the mites haemolymph. The mites that got the crystals on their feet soon died. He then decided to place some crystals on the hairy spikes on the mites back and these also soon died. As far as research into this is concerned, who will pick up the tab as nowdays the science goes where the money is.

  7. #6
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    Apr 2017
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    Default Re: questions and theories on how OA kills mites

    dudelt, I know they are dead when they drop because I do not bother oiling my boards. When an infected hive drops over 1000 dead mites in three days, one has to figure that they were dead when they dropped. Do not see anywhere near that without using the OAV.
    Thankfully, the bees are smarter than I am. They are doing well, in spite of my efforts to help them.

  8. #7
    Join Date
    Mar 2013
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    Seattle WA
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    Default Re: questions and theories on how OA kills mites

    I don't use sticky or oiled boards either but I have never noticed that mites have the ability to crawl back up into the hive. They may hitch a ride on a bee that passes by but I have not ever seen one crawling up the side wall of a hive. I believe many fall and die on the bottom of the hive. They may be dead when they fall but them being on the bottom of the hive is not proof they were dead before getting there.

    "If it is simply an action of grooming, why would OAV have such a greater efficacy than powdered sugar?" As I stated in the original post, "Could the oxalic acid react with the scent on the mites so they now show up to the bees as an intruder?" Sugar, in the form of honey, sugar water and nectar is a very common item in a beehive. If any of them had the ability to unmask the scent that keeps bees from finding them, there would probably be no mites in our hives. Therefore, I would doubt powdered sugar would unmask the scent on the mites but OA might react with it. That would make OA much more effective.

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