OAV and ousted dead mites
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  1. #1
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    Default OAV and ousted dead mites

    I am in the middle of a OAV series where I am doing an OAV treatment every 5 days (planning on 3 treatments total). I did my second one this morning and as I was putting the mouse guard back on the hive I saw mites being flicked out of the hive. It was really cool to see, I never watched the entrance closely immediately after the other treatment so this was new to me and really fascinating. It was just a few moments after I removed the damp towel that sealed the entrance during the final 10 minute time period after removing the wand. I watched for a few minutes an saw at least 35-40 mites on the entrance landing area. I would assume this is normal, but I was surprised to see the dead mites being booted out so fast after the treatment. That really shows me that OAV does a great job of killing mites and doing it quickly.


    Now the bittersweet part of that....

    1) I am glad to be killing mites, but with that being my second OAV treatment in 5 days is it worrisome to have that many mites being flicked out the entrance right after Treatment? I did my last alcohol wash and it showed 1 mite but that was about six weeks ago. I wanted to use OAV to knock potential mite problems down as much as I can at this point. I know populations build quickly this time of year so I wondered how worried I should be.


    2) with treating every 5 days, should I do more than three treatments? I am leery of removing boxes to do another alcohol wash to see where my numbers are since I don't want to disturb the propolis seals and the winter prep the bees have done if I don't have to.


    3) Overall is this too little too late since I started in mid October? I should have down this earlier before the "winter bees" were being reared but did I completely miss the boat on this?


    Thanks!

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  3. #2
    Join Date
    Jul 2014
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    Chapel Hill NC
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    Default Re: OAV and ousted dead mites

    3 treatments at 5 days will not cover the full brood cycle for the winter bees, nor drones. Do at least 6 total treatments with OAV every 5 days. It's probably too late to use Formic Pro (2 strips 14 day treatment) 100% mite kill pretty much, which is what I usually use in August to really hammer the mites in the capped brood.

    OAV will work fine but do more than 3 total treatments. Try at least 5 treatments. If you are still getting heavy mite drop. Pull sticky boards out every 48 hours after treatment to see how many mites. Keep treating need v healthy going into winter.

  4. #3
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    Default Re: OAV and ousted dead mites

    Yes, do four if you're using 5 day intervals. That's a 16-day treatment period, which will span a pupal brood period. Three tx on 5 day intervals only takes 11 days to complete, and that doesn't cut it, since workers pupate for 12 days, more or less.

    Sorry to say mites don't die that fast after treatment, nor are they flicked out by the bees. You were seeing something else.

    Yes, treatment earlier would have protected your winter bees more effectively. But that wouldn't have been OAV, but some other chemical. In future years when you have protected the bees with a very well-timed broodless period OAV during the early winter of the previous year you may be able to wait until OAV is once again highly effective ( i.e. now when brood is winding down.) But if you take that route you will need to monitor constantly all season to catch the occasional late summer surge that needs suppressing earlier than when OAV is truly effective.

    Whether (or not) waiting all year until mid-fall to treat again with OAV is a feasible plan for you can only be discovered through careful, regular monitoring all next summer. All kinds of factors may upset that plan. If you want to go that route, though, monitoring will allow you to give it a try, safely. I can get away it with most years, perhaps only needing summer treatment one year out of four.

    Be sure to wear your personal protective gear, WITHOUT FAIL.

    Nancy

  5. #4
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    Apr 2017
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    Default Re: OAV and ousted dead mites

    To answer your question, its entirely normal to see that kind of mite drop after a second treatment. Remember, OAV doesn't kill any of the mites that are under sealed brood. You are essentially seeing a kill off of mites that have emerged with new nurse bees over the last 5 days. Really shows you how many mites are in there! It's said that 80%, or even more, of your total mite load are currently under capped brood - this is exactly why we do multiple treatments.

    On my solid bottom boards I will see the bees hauling off "things" but haven't really seen them hauling off mites...but haven't looked. Hygenic bees keep my solid bottom boards VERY clean.

    I do a 4 day, 4 treatment cycle to catch all the mites. It's said the OA crystals last about 3 days in a hive and I want to keep them on there for a capped brood cycle. This keeps any mites from entering cells and kills the emerging ones all the way to the last cycle. I also treat all my hives at the same time to prevent any drift of an infected hive reinfecting a newly treated hive.

    As for OAV treatments working quickly. I have to agree with you!! On my last round of treatments I cleaned my mite boards before each treatment and counted the drop after about 30 minutes and there were loads of mites! Many of them were squirming around or on their backs with their legs wiggling. I cleaned off the boards and checked again in 12 hours, not as many but still a few. Checked them again after 24 hours and even fewer. From my experience the mite drop is almost instantaneous to the crystallization of the OA. As the crystals physically damage the mites it only makes sense that they would fall down, even if they're trying to get away from what's causing the injury and dropping at free will in at attempt at escaping it. As the damage is already done they undoubtedly die, especially if you line your mite boards in any type of oil or other common products.

  6. #5
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    Default Re: OAV and ousted dead mites

    I have to agree with mtnmyke and the OP. The first time I did an OAV treatment I used new sticky boards so they were perfectly clean. 15 min after treating, one hive had dropped at least 50 mites, the others, far fewer. Since I use SBBs, I have never seen a bee dragging out the dead ones but it does not suprise me. When I drop a dead yellow jacket on the landing board, it take less than a minute for a bee to grab it and fly off, dropping it unceremoniously some distance from the hive.
    Thankfully, the bees are smarter than I am. They are doing well, in spite of my efforts to help them.

  7. #6
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    Default Re: OAV and ousted dead mites

    Treat your mites with OAV every 4 or 5 days. How many times! Once more after there ceases to be further mite drops would be just fine!

    In other words, I keep treating them as many times as it takes for any treatment series when brood rearing is active.
    Frank

  8. #7
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    Default Re: OAV and ousted dead mites

    I would guess that Indiana is a lot cooler than Virginia at this moment and most of my hives have cut back on brood rearing, not much open brood to be seen. so all those mites from emerging cells have no place to hide hence the so called surge in mites which were actually there all the time. Then we have the broodless observation hive where an OAV treatment will clear out all the mites so they were treated on Monday the 15th and by Wednesday morning around 37 mites had fallen. Thursday I treated them again and by this morning 10 more mites have fallen. I will give them a week and do them again and see what happens as it appears these mites are not that easy to wear out.
    Johno

  9. #8
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    Default Re: OAV and ousted dead mites

    The foundress(mother mite) can reenter a cell about to be capped soon after emerging with the new bee. The offspring are phoretic for a week or two, as they mature, prior to entering cells to reproduce.

    I'm not criticizing the 4 day treatment cycle as that is what I did back in late August /early Sept. However, one maybe missing killing some of the foundress mites. I was not too concerned as I was seeing less than a total of less than 20 dead mites over the three days following OAV.

    I did a one shot OAV this week to reduce population of mites that may have been missed with 4 day cycle earlier. Hives are broodless now, at my local.
    Zone 3b. If you always do what you always did, you'll always get what you always got!

  10. #9
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    Default Re: OAV and ousted dead mites

    Quote Originally Posted by BeeHoosier View Post

    3) ..... but did I completely miss the boat on this?
    Your hive has not crashed yet, so there is a good chance they might be alright. You may notice that the hive population over the winter months will drop at a higher rate than we would like to see. Stresses from mite pressure can take their toll on the bees, reducing their lifespan, which is a critical consideration for overwintering in our regions. I've treated late in the past and had hives survive the winter, but they never seem to be quite as robust in their spring build up.

    The best time for you to treat for maximum effectiveness probably would have been when you did your last alcohol wash. I find typically that peak mite infestations coincide with the start of Goldenrod bloom. I try to time my treatments to bridge that time period, just before and at the start of the GR bloom. If you still have supers on at that time, a formic treatment would be best. If supers are off, then a series of OAV treatments work great for me.

    Your experience is an example of why I rely mainly on the calendar to plan my mite treatments. The low mite count you had with your alcohol wash 6 weeks ago gave you a false sense of what was actually happening in the hive. Washes are a great tool to monitor mite levels, but if they are to be relied upon for treatment decisions then they need to be done more frequently. Hive conditions can change rapidly, especially in the fall months.
    To everything there is a season....

  11. #10
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    Default Re: OAV and ousted dead mites

    Quote Originally Posted by enjambres View Post
    Sorry to say mites don't die that fast after treatment, nor are they flicked out by the bees. You were seeing something else.


    Nancy

    As always I appreciate your detailed response and you are always so very helpful. I will perform a few more OAV treatments in my series as you suggested. However, seeing the mites being flicked (for lack of a better term) out of the hive was true. I was fascinated because I didn't think that would happen. It was really cool to see. I use a metal type mouse guard/reducer with the small round holes for the bees to come and go and as I watched the entrance board (I use solid bottom) there were tiny rust colored dots being expelled onto the landing. It was almost like they were being kicked/flicked (I know that description sounds funny but that is the best way I can describe it). There would be tiny rust colored dots expelled onto the entrance board. I took my gloved finger and pressed on them to get them to stick to my finger and looked at them with a magnifying glass to be absolutely sure they were mites.

  12. #11
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    Default Re: OAV and ousted dead mites

    I do have to disagree with Nancy on this one as well.

    Since I'm in the middle of a treatment, and out of curiosity, I checked my boards about ten minutes after treatment and there were definitely mites, not much anything else since they were just cleaned.

    I checked again after an hour and a fairly large mite fall! Again, not much anything else as far as wax cappings, etc. (I treat at night)

    I also have my reducers on the large setting and noticed a large amount of dead mites on the landing board in front of their entrance. They are DEFINITELY moving mites out of the hive after they drop - at least on these hives with the solid bottoms. I also noticed a LARGE amount of dead mites wedged under the entrance reducers - since I have to remove them to fit my OAV in there.

    I can safely deduct that you do get a good kill almost immediately. I imagine as mites emerge from capped cells and are exposed to the OA crystals they may crawl off and try to escape their death by wedging themselves into random areas of the hive, only to die there.

    This was my 3rd treatment of 4. Still sad to see how many mites are "missed" because they are hidden under cappings.

  13. #12
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    Default Re: OAV and ousted dead mites

    Randy Oliver OAV Efficacy.jpg

    Here's some of what Randy Oliver's research documented. How soon on day one was not specifically mentioned but it might be fair to assume the "disturbance" of the third treatment could also be dislodging results/remnants from the two previous treatments.
    “The single biggest problem with communication is the illusion that it has taken place.” -George Bernard Shaw

  14. #13
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    Default Re: OAV and ousted dead mites

    True. Since the bees fan the OA around the hive and seem to get a little more active it could definitely bee weaker mites from previous treatments.

    I checked the mite board this morning and there really weren't many more mites on it. It was actually quite clean. I definitely noticed the most amount of drop after the first hour.

    Maybe in the spring, when I treat again, I"ll have to keep better track - even count the mites after each treatment with different times between counting. Could show some interesting data.

    Glad I'm knocking the mites down though. This 3rd treatment showed the least amount of mite fall yet.

  15. #14
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    Default Re: OAV and ousted dead mites

    Just done a 3rd round of OAV on my observation hive and had 3 mites on a white cardboard placed under the hive within 5 minutes. The mites come out of a vent under the hive with about an inch circular opening so I am also of the opinion that OAV works fast in some instances when the mite gets a good covering and that the bees also chuck them out.
    Johno

  16. #15
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    Default Re: OAV and ousted dead mites

    Hard to see, but as I was discussing earlier there were mites stuffed into the cracks around my entrance reducer. I didn't notice this on my second round, but the 3rd - this is what I saw.

    Because I treat at night, it was hard to get a good photo, but this one gets the point across.

    2018-10-22 19.52.49.jpg

  17. #16
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    Default Re: OAV and ousted dead mites

    My IPM boards fit rather loosely under the hives. Enough so that the bees can access the board easily. Prior to each treatment I scrape the boards clean to get a good count after application. On the hive that had the highest count, there were no mites remaining in the center of the board. However the edges where it sits tighter to the hive was packed with mites. My guess is that the bees consider the IPM board as part of the hive and were doing a little housecleaning. The mites that did not get hauled out got swept under the proverbial rug.
    Thankfully, the bees are smarter than I am. They are doing well, in spite of my efforts to help them.

  18. #17
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    Default Re: OAV and ousted dead mites

    well what happens is U treat for 4-7 weeks in a roll almost 0 mites -- then like today 64 degrees bees flying good --the bee keeper down road 1/2 mile is treatment free -of course they buy bees every year ---guess what their bees are working the same flowers that your bees are working and the drones come up for visit --that,s why U really got to do the alcohol wash quite often

  19. #18
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    Default Re: OAV and ousted dead mites

    For the first time ever this year I also saw dead mites in the entrance of a dbl nuc and maybe two other hives that was OAVap with a wand. I had lots of mites this year, even on hives that I sugar rolled with a count under 4. Late season infestation I believe from robbing. There is an interesting discussion on Bee-l on this subject. It is lengthy but informative, by Richard Cryberg:
    "My concern in that area
    is that there is a wide variation in treatments from 3 times 5 days apart
    to up to nearly 30 days at varying intervals. That also biases the outcome."

    I think we know the following about OVA:
    1. It is only effective against phoretic mites, but is very highly lethal to phoretics
    2. After application it takes about four days to kill all the phoretic mites.
    3. After application it is only effective for about four days and it is not clear at all that an application kills any mites that emerge more than a day or two after application.
    4. The % of total mites that are phoretic can range from as low as 15% to as high as 100% depending on a complex variety of factors I do not understand at all well other than it is very influenced by amount of brood.
    5. Brood tolerates multiple OAV treatments with no harm at all.

    So, I spent quite a bit of time playing "what if" with Randy's mite model spread sheet. I played with application intervals, numbers of applications and time of year. One of my major interests is how to control mite population growth during spring to fall when brood is present. A lot of my interest was driven by the various suggestions on timing and number of treatments. Now, Randy's model does not automatically accommodate any treatment interval less than twice a month. So, in some cases I had to do some manual calculations and enter a total % kill for more than one treatment. This is easy enough to do. I looked at things ranging from several treatments at five day intervals, to several treatments at twice a month or even less often intervals.

    What I learned from this was final mite counts in late fall when going into winter depended very little on treatment intervals. You could treat at five day intervals for five treatments or you could treat twice a month for five treatments and the October mite numbers were very close to the same. What was really important was the total number of independent treatments during periods where brood is present. An independent treatment is simply a treatment far enough time wise from other treatments that the two have no over lap in kill. Thus, based on the results from Randy's model I think getting hung up on treating every five days or every seven days or even every fourteen days is a mistake. In any of these cases what really matters is the total number of treatments. In my climate it looks to me like you need five independent treatments. It also makes very little difference when you do those five treatments. One in June, two in July and two in August are just as good at holding the Oct 1 mite counts down as two in August and three in Sept. One caution thou. I live in an area of low hive density and nearly zero ferals. So, the mite immigration numbers I used were at the low end of Randy's model. A high immigration rate would likely need another treatment or two in Oct along with the earlier five treatments althou I did not run such cases in the model.

    There is one factor that may say spaced out treatments are even better. While no one has reported data that says multiple OVA treatments of adult bees harms them it is hard to believe there are zero negative effects. By spacing treatments out at least two weeks apart each adult bee experiences only a couple of treatments during its life on average. As long as you do an equal job of controlling mites less treatments during any given bees life seems to be a move in the right direction.

    Of course if you have any concern at all about how good a job you have done you can always do a broodless OAV in Nov or Dec and take the counts down to effectively zero. But, as it is viruses that actually kill the hive my thinking is you want is to get the counts low in Aug so you are set up to raise healthy winter bees. If you simply kill mites on bees that are loaded with viruses you are too late and are going to get a dead hive even if the mite count is zero after the broodless treatment.

    I strongly encourage everyone to spend several hours with Randy's model and learn the population dynamics of mites in your area. There is a huge amount of information crammed in that model. I must have spent fifteen hours playing with it so far and am sure I am not done learning.

    One caution. I live in NE Ohio and put in brood patterns for my local area. If you live 200 miles south of me you need to enter different data than I entered and you should expect to see different mite build ups versus month of the year. That could easy demand one or two extra OVA treatments versus what I think is adequate for me. I should also add at my location and with the bees I run I am more and more coming to the conclusion that anything above a 1% by an alcohol wash on August 1 is time for me to start to get concerned, particularly on big production hives. If you are convinced your bees are ok with a 3% August 1 wash you will get by with fewer treatments than I think optimum for me. Randy's model allows you to pick your % targets as you see fit. It does seem clear based on largely anecdotal stories that if you live where your bees brood much of the winter you can tolerate higher mite %s than I can tolerate with my long cold winter. If your bees are brooding you have a constant supply of new bees coming along where the bees in my hives today are pretty much the same bees that will be in my hives next March 1. Those younger bees can compensate for older bees dying early in a warmer climate. Where I live older bees dying early ends up with a hive too weak to make it by March due to a small cluster that can not make enough heat to recover.

    I sure welcome arguments about why I am wrong and what I have missed. Mites are a real pain. I wish every one of them was dead. I do not like suggesting such a large number of treatments even if it is dirt easy to do with a Provap. I can do a hive a minute easy enough. But, I still hate doing so many treatments.

    Dick
    Proverbs 16:24

  20. #19
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    Default Re: OAV and ousted dead mites

    Quote Originally Posted by Cloverdale View Post
    It also makes very little difference when you do those five treatments. One in June, two in July and two in August are just as good at holding the Oct 1 mite counts down as two in August and three in Sept.
    Dick
    You've sparked my interest in working with Randy's mite model. Like Dick, I live in NE Ohio so his results will probably be similar to mine. I've always treated 3 or 4 times in the fall with pretty good results. Maybe I should be considering 5 rounds.

    In this part of the state there is still a pretty good nectar flow that continues through June and July, so the August - September treatment time period works better for not having supers on the hive with open nectar. June - July would not work for me.
    To everything there is a season....

  21. #20
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    Default Re: OAV and ousted dead mites

    Someone somewhere said that beekeeping was local, so bearing that in mind every bodies treatment has to work in his locality. If you cannot treat with honey supers on, in my locality I can treat in almost 10 months of the year as I have only one nectar flow of rarely more than 8 weeks. Some of you lucky guys in other areas have flows spring and fall so you have to treat in between the flows. However at any time during the year OAV should get up to 20% of you mite load per treatment and they should receive the treatments before the brood period maxes out so one needs as many treatments as is necessary to get mite numbers down. At present my colonies including an observation hive will get up to 12 treatments per year and I will rarely see a deformed wing bee. I also find that the experts who have claimed that OAV is not suitable for treatment of colonies with brood have had a change of mind after many who have been using it for years have been ignored.
    Johno

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