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  1. #1
    Join Date
    Apr 2008
    Location
    Madison County, Alabama
    Posts
    487

    Default Varroa Mite Count on Sticky Boards

    What daily number is enough to prompt you to treat?

    20 per day?
    50 per day?
    10 per day?
    5 per day?
    Other answer?

  2. #2
    Join Date
    May 2005
    Location
    Knoxville, TN
    Posts
    1,933

    Default

    depends on the method of 'sticky board', location, and time of year.
    The stickier the trap, the more mites you will get. We use shelf liner
    under a metal screen with wooden frame to keep bees from entering.
    I've trapped 'less' using a board with Crisco, and 'more' using that yellow
    insect trap paper (forgot what its called). There's at least one study that
    says your stickiness has an effect.

  3. #3
    Join Date
    Jul 2005
    Location
    Signal Mountain, Tennessee
    Posts
    30

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    A state apiarist once told us in a class that a 50 mite drop in a 24-hour time period is the threshold to treat so that's what I've gone with. Below that threshold, I continue to periodically monitor.
    JustBob
    Moderation in all things...

  4. #4
    Join Date
    May 2005
    Location
    Knoxville, TN
    Posts
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    Economic threshold for Varroa jacobsoni in the southeastern USA. Delaplane, K.S. & W.M. Hood. 1999. Apidologie 30: 383-395

    ABSTRACT This research was designed to determine economic thresholds for Varroa jacobsoni mites in mature overwintered colonies under conditions that encourage or discourage mite immigration. Congruent data from the present study and our earlier work suggest that a true late-season (August) economic threshold for mites in the southeastern USA lies within a range of mite populations of 3 172-4 261, ether roll mite levels of 15-38, and overnight bottom board insert mite levels of 59-187 in colonies with bee populations of 24 808-33 699. Overwintering colonies can benefit from an additional early-season (February) treatment. This benefit was realized in colonies which in February had the following average values: mite populations 7-97, ether roll 0.4-2.8, bottom board inserts 0.6-10.2 and bee populations 12 606-13 500. Continuous acaricide treatment never achieved colony bee populations or brood number significantly higher than in colonies treated more conservatively. There is evidence that minimizing mite immigration has the benefit of delaying the onset of economic thresholds.

    http://www.ent.uga.edu/bees/Research/archives.htm
    Last edited by MichaelW; 09-10-2008 at 08:59 AM.

  5. #5
    Join Date
    Apr 2007
    Location
    Northern Virginia
    Posts
    764

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    Interesting.

    Although if I used an ECONOMIC threshold for anything as a small time hobby beekeeper I may never would have started with it at all.

    Just good to note the difference between recommendations based on an economic threshold and what you as a beekeeper are comfortable with as a tolerable/acceptable level of mites and the risk associated.
    karla

  6. #6

    Default

    Quote Originally Posted by MichaelW View Post
    10.
    Quote Originally Posted by MichaelW View Post
    overnight bottom board insert mite levels of 59-187
    Michael, if the study you're quoting says 59 - 187, why do you recommend treating at 10? I'm not being critical, just curious.
    Dan www.boogerhillbee.com
    Experience is a hard teacher because she gives the test first, the lesson afterwards

  7. #7
    Join Date
    May 2005
    Location
    Knoxville, TN
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    Default

    Dan,
    I'm not recommending ten. I just cut and pasted that off UGA's website
    and it was #10 on their list of research articles. I went back and took
    out the #10 to prevent confusion.

    karla,
    Ideally, economic thresholds are going to be the same for hobby operations
    as profit oriented ones. Its just a term and calculation used to determine
    how much of an infection from a pest it takes to significantly damage the
    host. Generally speaking, treating crop/livestock systems that have pests
    below 'economic threshold' causes more harm then good. That is how systems
    get on the 'pesticide treadmill', which involves a myriad of problems. All of
    this can be measured in economic terms, which is a convenient way to make
    determinations.
    Last edited by MichaelW; 09-10-2008 at 09:00 AM.

  8. #8
    Join Date
    Sep 2007
    Location
    Fayetteville, AR, USA
    Posts
    144

    Default

    this is from 'Economic Threshold for Varroa on the Canadian
    Prairies'
    http://www.capabees.com/main/files/p...athreshold.pdf

    based on research done in Manitoba they found that a natural drop mite count (assuming 24 hrs) of 18 mites is appox 3% infestation and 33-43 mites is a 5-6% infestation. they recommend treating in early fall when the mite infestation is >3% and treating in the late fall when the mite infestation is >10%.

  9. #9
    Join Date
    Apr 2007
    Location
    Northern Virginia
    Posts
    764

    Default

    Quote Originally Posted by MichaelW View Post
    Ideally, economic thresholds are going to be the same for hobby operations as profit oriented ones. Its just a term and calculation used to determine
    how much of an infection from a pest it takes to significantly damage the
    host. Generally speaking, treating crop/livestock systems that have pests
    below 'economic threshold' causes more harm then good. That is how systems
    get on the 'pesticide treadmill', which involves a myriad of problems. All of
    this can be measured in economic terms, which is a convenient way to make
    determinations.

    THanks for clarifying. I guess I thought economic threshold meant is it worth it cost wise to treat.. and for a hobbiest, at least for me, that is really a non issue or else we never would have started. sort of like my $50 cantelopes! But boy are they good!
    karla

  10. #10
    Join Date
    Apr 2000
    Location
    Birmingham, West Midlands, UK
    Posts
    751

    Default

    This is a difficult one. The mites round here are well loaded with viruses, and I worry that they may affect drone performance. On the other hand, if I never let mite numbers rise, I can't spot the more resistant hives. It's a question of finding the right balance somehow.
    RSBrenchley@aol.com
    Birmingham UK

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