Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?
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  1. #1
    Join Date
    May 2015
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    Default Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    I did my third treatment to my two hives on Saturday and just this morning got around to removing the 1/4' plywood I've been placing under the hive for treatment. I see (what I consider) LOTS of dead mites on the board. The board is not marked but I'd estimate at least 1-2 mites in each square inch on the board. With those numbers after the 3rd treatment, what do y'all think - go for another round?

    Some background...
    I have not done any sugar or alcohol roll. Nor have I used the IPM board at any other time for checking mites. I had little doubt my hives had some mites so I proceeded with the Oxalic Acid vapor treatment - doing a treatment once every 7 days for 3 cycles. Saturday was my 3rd one. I also removed the plyboard after previous treatments - so no count for comparison. The hive looks very healthy overall... packing away syrup, lots of bees in a deep plus 3 mediums. No visible signs of DWV (this hive had that in the late winter and I used MAQS then).

    So I know I haven't been very analytical on this but I'm wondering if the general thought is "if you see that many dropped mites after the 3rd treatment, then go ahead with another treatment".

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  3. #2
    Join Date
    Mar 2016
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    St. Michael, MN
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    I did my third treatment Friday (5 day cycle). On Saturday I had 300 mites and on Sunday I had 367 on the bottom board in one hive. I'll be doing a fourth on Wed. Then I'll do a sugar roll the following Monday. So far, I've killed almost 2000 mites in one hive after 3 treatments.

  4. #3
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    May 2015
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    Thanks for the info, Gumpy. Is your plan to continue the treatments until you have a zero (or near zero) count on the bottom board? My understanding is that OAV is not bad on the bees but I'm wondering where the logical/practical stopping point is.

  5. #4
    Join Date
    Jan 2014
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    Louisville, Colorado, USA
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    I always do 4 treatments this time of year. If they need a 5th, I do it.

  6. #5
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    Sounds good. How do you determine "if they need it"? Based on a sugar roll after the 4th treatment or checking the mite drop on bottom board?

  7. #6
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    Mar 2016
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    I don't think a zero mite drop count is realistic, considering I don't know where my bees are going and whether they might be robbing out someone else's mite bomb and bringing mites back.

    I'll see where the sugar roll puts them after the fourth treatment. I had a sugar roll count of 7 on this particular hive at the end of August, prior to treatment. If I can get it to 2 or under, I think I'll be good. I'll probably do one final preventive treatment before winter sets in in late Nov or early Dec.

  8. #7
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    Jan 2016
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    Victoria, Texas
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    3 treatments only cover 14 days, not 21 if you are doing them weekly, and if that's your target.

    I did four treatments, and still had 91 mites, so I went for a 5th treatment. I'll check the bottom board to see if I finally got them all.
    Never argue with drunks or crazy people!
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  9. #8
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    Jan 2014
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    I gave up on sugar rolls as they are wildly inconsistent in my opinion.
    I look at the mite drop. If it has gone down to 20 or so after the 4th treatment I think the bees are good to go until the one-off treatment at the end of November.

  10. #9
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    May 2015
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    Quote Originally Posted by Wandering Man View Post
    3 treatments only cover 14 days, not 21 if you are doing them weekly, and if that's your target.
    So glad you pointed this out! I was thinking my 3 treatments covered the 21 days but not at all. It covers 14 only. The 4th treatment next Saturday will be the end of the 21 day cycle. So that'll be my plan for now and I'll watch the bottom boards after that 4th to assess.

    Thanks to all.

  11. #10
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    Even if you have no mites drop afterward, or a very low % on a sugar roll, don't omit that final one shot after Thanskgiving/before Christmas. I think it is the most valuable treatment of the whole year, and well worth the modest trouble of doing a one-shot on each hive.

    Enj.

  12. #11
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    Quote Originally Posted by enjambres View Post
    Even if you have no mites drop afterward, or a very low % on a sugar roll, don't omit that final one shot after Thanskgiving/before Christmas. I think it is the most valuable treatment of the whole year, and well worth the modest trouble of doing a one-shot on each hive.

    Enj.
    Yes - I definitely plan to do the one-shot winter treatment. My understanding is this one has a high impact as there's the least brood. The difficulty for us (in the South Carolina) is we can have mild winters and thus may have brood throughout the season. We'll see how this year's winter plays out.

  13. #12
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    Quote Originally Posted by Matt_inSC View Post
    So glad you pointed this out! I was thinking my 3 treatments covered the 21 days but not at all. It covers 14 only.
    I don't want to discourage anyone from doing a 4th or greater OAV treatment if the colony needs it, I usually just do 3 but I did 4 this year too. The weather allowed for extended brood rearing and the mite populations climbed pretty high in Aug-Sept.

    I believe the 3 treatments, 7 days apart schedule covers a 21 day brood cycle period based on the "capped brood" after the initial 1st treatment. All of the capped brood at the time of the first treatment will have emerged 14 days later, and on the 3rd treatment all bees will have been exposed to OAV. I know there is not 100% efficacy, and the residual effect of the crystals may not last the entire 7 days until the next treatment, but under normal circumstances "most" of the mites will have been impacted after the 3rd treatment.

    There are always some mites that escape the OA and end up under capped cells, so you can't get them all. But after the 3rd treatment one should expect to see the fall drop off rapidly with each successive additional treatment.
    To everything there is a season....

  14. #13
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    I checked the sticky board on one of the backyard hives this AM after the 4th treatment. About 150 mites. That's down from over 300 mites last week (3rd OAV).

    Those 150 mites the first three treatments missed are unacceptable. But that's just me.

  15. #14
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    Quote Originally Posted by Arnie View Post
    I checked the sticky board on one of the backyard hives this AM after the 4th treatment. About 150 mites. That's down from over 300 mites last week (3rd OAV).

    Those 150 mites the first three treatments missed are unacceptable. But that's just me.

    Do you know what your total mite drop count is on that hive for the entire regiment?

  16. #15
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    No, I didn't keep track of the totals. But if I recall correctly probably around a thousand give or take.

    I think over a thousand is a lot of mites, but I really don't know what others get. I treated that hive three rounds in spring since I didn't split that one.

    I despise those dang mites.

  17. #16
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    Quote Originally Posted by Arnie View Post
    No, I didn't keep track of the totals. But if I recall correctly probably around a thousand give or take.

    I think over a thousand is a lot of mites, but I really don't know what others get. I treated that hive three rounds in spring since I didn't split that one.
    Just curious. I started another thread asking this same question but had only a few responses.

    I finished my third 5-day cycle treatment on Friday. As of today I have killed 2100 mites on one 3-deep hive that was started as a 5 frame nuc of CA bees in May, has had no other treatments, and has thrived through the summer. It had a sugar roll count of 7 at the end of August. Just trying to figure out what average is.

  18. #17
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    I am the wrong person to ask.
    I do the OAV on a schedule. 4 treatments once a week after the supers come off.
    The single treatment around the first week of December.
    And in spring, if I don't split a colony it gets 3 treatments once a week.

    I keep track of mite kills to see the numbers and reassure myself the hives have fairly low mite populations.

    Some beeks recommend to treat only if you have high numbers in a test.
    I feel I don't want to wait until numbers get high, I would prefer to keep them low.
    Preventive maintenance.

  19. #18
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    Algoma District Northern Ontario, Canada
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    Default Re: Visible mite drop after 3rd round of Oxalic Acid vapor - go for 4th round?

    Quote Originally Posted by Arnie View Post
    I am the wrong person to ask.
    I do the OAV on a schedule. 4 treatments once a week after the supers come off.
    The single treatment around the first week of December.
    And in spring, if I don't split a colony it gets 3 treatments once a week.

    I keep track of mite kills to see the numbers and reassure myself the hives have fairly low mite populations.

    Some beeks recommend to treat only if you have high numbers in a test.
    I feel I don't want to wait until numbers get high, I would prefer to keep them low.
    Preventive maintenance.
    That is the way I roll too! Four rounds 6 days apart and now only getting one or two mites a week on the one hive I have a screen and sticky board on . The other 12 colonies got the same medicine. I might do another single vaporization later as there is still a bit of capped brood.

    If I was seeing mite drop after the 4th treatment I would continue more treatments. I have seen no mortality (other than a few who fall into the vaporizor) and have no winter losses over 3 complete winters with 5 to 7 hives.
    Frank

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