Mite count
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Coral Conant Gilles
Jul 17, 2016, 9:52:09 PM7/17/16
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I did a mite count using Randy Oliver's method of sprinkling powdered sugar over the top of the frames and collecting mites on a sticky bottom board over 24 hours. But I'm having trouble figuring out how to interpret my results. This method should equal 30-50% of the mites in the hive. I counted librally and got 245, so total population of 490-735 mites for a hive of 5 mediums. I'm sick, so I didn't do an inspection, but there were bees covering every inch of the top of the hive. Thanks.
Coral
Matthew Hennek
Jul 17, 2016, 10:13:01 PM7/17/16
to madbees
The Internets tell me there are ~20k bees per deep box. Since a medium is approximately 2/3rds of a deep, if your hive is truly packed full of bees you have approximately 67k bees.
Assuming Randy's is getting 100% of the phoretic mites and you double it to include the mites in the brood, you're infestation level is approximately 1%.
I think this is probably a gross underestimate and would recommend you do an ether/alcohol shake of 1/2 cup (300) of bees.
mar...@chicagobees.com
Jul 17, 2016, 10:25:40 PM7/17/16
to madbees
I agree with Matt. Do an alcohol wash or sugar roll with 1/2 cup of bees and you'll get a better count of the mites. Select young nurse bees from a frame that has older larvae ( make sure the queen is not on the frame when you collect the bees ).
I've seen ants carry away mites from the inspection board. It's a good tool to utilize but I wouldn't rely on sticky board to estimate the mite levels in the colony.
The Internets tell me there are ~20k bees per deep box. Since a medium is approximately 2/3rds of a deep, if your hive is truly packed full of bees you have approximately 67k bees. Assuming Randy's is getting 100% of the phoretic mites and you double it to include the mites in the brood, you're infestation level is approximately 1%. I think this is probably a gross underestimate and would recommend you do an ether/alcohol shake of 1/2 cup (300) of bees. -- You received this message because you are subscribed to the Google Groups "madbees" group. To unsubscribe from this group and stop receiving emails from it, send an email to madbees+u...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Matthew Hennek
Jul 17, 2016, 10:28:06 PM7/17/16
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I misspoke. Assuming your number of 735 mites is correct based on Randys experiment with a 4 frame nuc is correct, your infestation is about 1%.
My issue with translating his experiment to a full size hive is that it assumes the drop will be the same. In his experiment there was only a single level (he also talks about a double deep) while you have a 5 box hive (many steps for the mites to land on). The mites in the top boxes have much greater opportunity to not fall through a screened bottom board and crawl back on the bees than in a single box or even a double deep.
While it may be useful for varroa control, I'm not sure how good it is as a tool to judge infestation rates.
capitalb...@tds.net
Jul 18, 2016, 9:32:13 PM7/18/16
to madbees
Attached is a graph from Dr. Rob Currie who at the time (2008) was at U of Manitoba and ran some comparisons of 48 hour sticky board and alcohol wash results...this is phoretic mite counts only, he did not adjust to account for mites under the caps in this chart so it was intended to provide some form of correlation between those two directly....it wasn't a large number of data points and most were lower mite levels but it may provide some guidance.
Matthew Hennek
Jul 18, 2016, 9:44:51 PM7/18/16
to madbees
Unfortunately the range of that graph seems to be not in the range for beekeepers. With the highest data point being 0.25 mites in 100 bees, it's way too low to be of any use. At the exponential rate of tbst graph one would expect thousands of mites in a 24 hour drop if the mite load was in the 2-6% that beekeepers often see. Or perhaps I'm not reading it right.
Matthew Hennek
Jul 18, 2016, 9:47:34 PM7/18/16
to madbees
Were these natural drops or drops after some sort of treatment. I ask because I've never seen that many mites on a Crisco covered board.
jeanne hansen
Jul 19, 2016, 12:11:28 PM7/19/16
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Matt,
I'm sure you are misinterpreting that graph. He doesn't mean 0.2 mites per 100. He means two mites divided by 100 equals 0.2.
From: Matthew Hennek <matthew...@gmail.com>
To: madbees <mad...@googlegroups.com>
Sent: Monday, July 18, 2016 8:44 PM
Subject: [madbees] Re: Mite count
Unfortunately the range of that graph seems to be not in the range for beekeepers. With the highest data point being 0.25 mites in 100 bees, it's way too low to be of any use. At the exponential rate of tbst graph one would expect thousands of mites in a 24 hour drop if the mite load was in the 2-6% that beekeepers often see. Or perhaps I'm not reading it right.
--
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Matthew Hennek
Jul 19, 2016, 12:27:21 PM7/19/16
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You sure? X axis label reads "mites per 100 bees"
Can you link or post the original article? It might be a good read.
I recently came across a couple of interesting journal articles talking about impacting mites ability to chemically discern forage bees vs nurse bees. The logic goes that if you can prevent mites from being able to select nurse bees as a host your counts will drop because the mites will spend more time out of the hive on forage bees (which also have a higher mortality rate).
Coral
Jul 19, 2016, 2:13:30 PM7/19/16
to madbees
So, I chose the sugar count because it seemed more reliable than an alcohol wash (and easier). In line with what you're saying, extrapolating an alcohol wash from 100 (or 300) bees isn't accurate either. If I extrapolate from nurse bees my count will be exaggerated. If I extrapolate from forgers, my count will be far too low. Is there just no way to get a good count?
Thanks.
Joseph Bessetti
Jul 19, 2016, 2:33:13 PM7/19/16
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Welcome to the challenges of mite counting!
There's also the question of what you hope to do with the numbers. Most of the time this means deciding what number of mites will trigger action, and what action you wish to take.
Joe
There's also the question of what you hope to do with the numbers. Most of the time this means deciding what number of mites will trigger action, and what action you wish to take.
Joe
> Date: Tue, 19 Jul 2016 11:13:30 -0700
> From: cdco...@gmail.com
> To: mad...@googlegroups.com
> Subject: Re: [madbees] Re: Mite count
> From: cdco...@gmail.com
> To: mad...@googlegroups.com
> Subject: Re: [madbees] Re: Mite count
>
> So, I chose the sugar count because it seemed more reliable than an alcohol wash (and easier). In line with what you're saying, extrapolating an alcohol wash from 100 (or 300) bees isn't accurate either. If I extrapolate from nurse bees my count will be exaggerated. If I extrapolate from forgers, my count will be far too low. Is there just no way to get a good count?
>
> Thanks.
>
> --
> You received this message because you are subscribed to the Google Groups "madbees" group.
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Matthew Hennek
Jul 19, 2016, 2:38:06 PM7/19/16
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Most of the observations/conclusions/recommendations that one reads is based on a sugar roll (in a jar) or alcohol/ether wash. While they may not give a true number of the total mites in a hive, the numbers they provide have been correlated to observed mite impacts of a hive. While I think some recommendations have changed, last I recall if an ether/sugar/alcohol roll finds more than 6 mites in a 300 bee (1/2c) sample, the hive is to the point where it can suffer damage and where one is recommended to treat if that is their nature. Rich Schneider or Larry would probably know the most up to date recommendations. It might have dropped to 3 mites per 300 bees...I forget.
http://scientificbeekeeping.com/sick-bees-part-11-mite-monitoring-methods/
http://scientificbeekeeping.com/sick-bees-part-11-mite-monitoring-methods/
Randy Oliver found that forage bees do not yield a representative sample of the hive's mite load and that there's no correlation between forage bees and nurse bees. This is probably because mites are known to preferentially select nurse bees 5 or 6 to 1 over forage bees (cite).
Since much of the damage that mites do is to developing brood and most of the mites prefer nurse bees, sampling the nurse bees probably gives you the best idea of whether the mite levels are too high.
Since much of the damage that mites do is to developing brood and most of the mites prefer nurse bees, sampling the nurse bees probably gives you the best idea of whether the mite levels are too high.
It sometimes seems like a bit of a crap shoot honestly.
Joseph Bessetti
Jul 19, 2016, 2:41:55 PM7/19/16
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I would guess that the actual number of mites per 100 bees on the x-axis ranges from 0 to 25 in that figure, and that the author's reference to "per 100" resulted in them setting the axis as a fraction representing %. Thus, 0.05 is 5 mites per 100, 0.10 is 10 mites per 100, and up. This would seem to make the numbers line up with my expectations.
I haven't found the original article yet, though this data could have been from a presentation as well. Currie has a list of publications on the University of Manitoba website: http://umanitoba.ca/faculties/afs/dept/entomology/personnel/Currie.html
Joe
I haven't found the original article yet, though this data could have been from a presentation as well. Currie has a list of publications on the University of Manitoba website: http://umanitoba.ca/faculties/afs/dept/entomology/personnel/Currie.html
Joe
> Date: Tue, 19 Jul 2016 09:27:21 -0700
> From: matthew...@gmail.com
> From: matthew...@gmail.com
> You sure? X axis label reads "mites per 100 bees"
>
> Can you link or post the original article? It might be a good read.
>
> I recently came across a couple of interesting journal articles talking about impacting mites ability to chemically discern forage bees vs nurse bees. The logic goes that if you can prevent mites from being able to select nurse bees as a host your counts will drop because the mites will spend more time out of the hive on forage bees (which also have a higher mortality rate).
>
>
> Can you link or post the original article? It might be a good read.
>
> I recently came across a couple of interesting journal articles talking about impacting mites ability to chemically discern forage bees vs nurse bees. The logic goes that if you can prevent mites from being able to select nurse bees as a host your counts will drop because the mites will spend more time out of the hive on forage bees (which also have a higher mortality rate).
>
> --
> You received this message because you are subscribed to the Google Groups "madbees" group.
> You received this message because you are subscribed to the Google Groups "madbees" group.
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Joseph Bessetti
Jul 19, 2016, 3:06:00 PM7/19/16
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Coral,
The method that you used, adding sugar to the entire hive and counting mite drop, is more difficult to standardize and interpret than most of the other methods that have been suggested. What you did is akin to measuring knock-down after chemical treatment, which is often done as a way of measuring the effectiveness of the treatment. However, an alcohol wash or powdered sugar roll is generally performed before and after the knock-down.
My personal suggestion to you is this: Read up on the powdered sugar roll method. I like this method over the alcohol or ether because it is not supposed to kill the bees, and I'm going to suggest that you do multiple sugar roll counts, perhaps as many as 5 or 6 independent sugar rolls on the same day. As a technique that is new to you, this will give you some practice doing it without killing all those bees. Additionally, the accuracy of any measurement is reflected in how closely the result can be repeated. When you can do the test AND get about the same number mites multiple times, it will give you more confidence in both your ability to perform the test and in your result.
I demonstrated a sugar roll test a couple weeks ago, so I'm a novice myself. The main challenges that I see in it doing it are using enough sugar and shaking long enough and hard enough to get all the mites off the bees. I didn't start out with enough sugar (or had too many bees), so when I started shaking I didn't even get any sugar coming out of the jar. I added another tablespoon and a half and rolled them again, and then I was able to get some mites out. If I was unsure that I had gotten them all I would consider adding more sugar and shaking longer. If you don't use enough sugar or shake enough you will underestimate your population.
Good luck!
Joe
The method that you used, adding sugar to the entire hive and counting mite drop, is more difficult to standardize and interpret than most of the other methods that have been suggested. What you did is akin to measuring knock-down after chemical treatment, which is often done as a way of measuring the effectiveness of the treatment. However, an alcohol wash or powdered sugar roll is generally performed before and after the knock-down.
My personal suggestion to you is this: Read up on the powdered sugar roll method. I like this method over the alcohol or ether because it is not supposed to kill the bees, and I'm going to suggest that you do multiple sugar roll counts, perhaps as many as 5 or 6 independent sugar rolls on the same day. As a technique that is new to you, this will give you some practice doing it without killing all those bees. Additionally, the accuracy of any measurement is reflected in how closely the result can be repeated. When you can do the test AND get about the same number mites multiple times, it will give you more confidence in both your ability to perform the test and in your result.
I demonstrated a sugar roll test a couple weeks ago, so I'm a novice myself. The main challenges that I see in it doing it are using enough sugar and shaking long enough and hard enough to get all the mites off the bees. I didn't start out with enough sugar (or had too many bees), so when I started shaking I didn't even get any sugar coming out of the jar. I added another tablespoon and a half and rolled them again, and then I was able to get some mites out. If I was unsure that I had gotten them all I would consider adding more sugar and shaking longer. If you don't use enough sugar or shake enough you will underestimate your population.
Good luck!
Joe
> So, I chose the sugar count because it seemed more reliable than an alcohol wash (and easier). In line with what you're saying, extrapolating an alcohol wash from 100 (or 300) bees isn't accurate either. If I extrapolate from nurse bees my count will be exaggerated. If I extrapolate from forgers, my count will be far too low. Is there just no way to get a good count?
>
> Thanks.
>
>
> Thanks.
>
> --
> You received this message because you are subscribed to the Google Groups "madbees" group.
> You received this message because you are subscribed to the Google Groups "madbees" group.
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Matthew Hennek
Jul 19, 2016, 3:40:17 PM7/19/16
to madbees
Hey Joe,
My understanding of the sugar roll method (which I have tried and abandoned and prefer the ether roll), is that you don't want to shake the bees very hard/long or else they vomit/defecate (I forget which) and make a big sticky mess. You want to shake them only enough to coat the bees evenly with powdered sugar and then set the jar down and they groom the mites off before shaking all the powdered sugar out through the screen.
I guess what I'm saying is as with many things beekeeping, I've heard conflicting advice on how to do it.
Thoughts?
Joseph Bessetti
Jul 19, 2016, 4:54:04 PM7/19/16
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Hey Matt,
My limited experience is just based on attempts to follow the University of Minnesota Instructional Poster #155, plus my own observations. The instructions indicate to shake to coat the bees, let sit for about 1-2 minutes (you'd think a scientist would be more specific here), then shake the sugar out through a screen for at least 1 minute.
I haven't had any issues with the bees getting sticky, from which I can only conclude that I have not yet shaken them too hard. I agree that would be something to avoid.
I agree about the conflicting advice. However, with a procedure like this there is bound to be conflict. It is impossible to describe how "hard" to "shake", yet the assay is dependent on "shaking" to uniformly coat the bees and "shaking" to get the mites out of the jar.
Also, I think with my own bees I need considerably more sugar because they are much smaller and thus have more surface area. The only drawback I see of using too much sugar is making it harder to see the mites that do come out. I also shook a lot longer than 1 minute because I wanted to be sure I got them all. I even dumped an extra Tbsp of sugar in and shook the poor things again. I didn't get any more mites after the first minute. The bees appeared to be ok when I released them...
I'll have to get a lot more experience with the method before I fully endorse it, but I still tend to believe it can be effective despite a bit of a learning curve. I really like that the bees aren't killed, but I suppose they could crawl off and die somewhere. I'd probably use natural drop on sticky boards over alcohol or ether for that reason too , even though I know a couple hundred bees aren't a big impact on the population.
Joe
My limited experience is just based on attempts to follow the University of Minnesota Instructional Poster #155, plus my own observations. The instructions indicate to shake to coat the bees, let sit for about 1-2 minutes (you'd think a scientist would be more specific here), then shake the sugar out through a screen for at least 1 minute.
I haven't had any issues with the bees getting sticky, from which I can only conclude that I have not yet shaken them too hard. I agree that would be something to avoid.
I agree about the conflicting advice. However, with a procedure like this there is bound to be conflict. It is impossible to describe how "hard" to "shake", yet the assay is dependent on "shaking" to uniformly coat the bees and "shaking" to get the mites out of the jar.
Also, I think with my own bees I need considerably more sugar because they are much smaller and thus have more surface area. The only drawback I see of using too much sugar is making it harder to see the mites that do come out. I also shook a lot longer than 1 minute because I wanted to be sure I got them all. I even dumped an extra Tbsp of sugar in and shook the poor things again. I didn't get any more mites after the first minute. The bees appeared to be ok when I released them...
I'll have to get a lot more experience with the method before I fully endorse it, but I still tend to believe it can be effective despite a bit of a learning curve. I really like that the bees aren't killed, but I suppose they could crawl off and die somewhere. I'd probably use natural drop on sticky boards over alcohol or ether for that reason too , even though I know a couple hundred bees aren't a big impact on the population.
Joe
Matthew Hennek
Jul 19, 2016, 6:17:59 PM7/19/16
to madbees
Have you "calibrated" your shaker? With your small cell bees a half cup may be quite a bit more than 300. On a similar but different note, I've thought about bringing out a small digital scale. A volume measurement seems like it would have a lot of error factors in it (temperature comes to mind) that could be solved with a weight measurement.
Paul Zelenski
Jul 19, 2016, 9:49:08 PM7/19/16
to mad...@googlegroups.com
The bees her sticky during a flow when their honey stomachs are full. If you text the. When the flow isn't on, you will have much less sticky bees
Joseph Bessetti
Jul 19, 2016, 10:28:46 PM7/19/16
to mad...@googlegroups.com
That crossed my mind. There's probably about 400-450 of my bees in a cup, but I haven't counted them.
There are a couple items that come in handy when doing these kinds of counts. A tuppereware or other container large enough to shake a whole frame of bees into is one. Then a scoop of some sort to get roughly a cup of bees, and a funnel to get them into the shaking jar. If you incorporated a digital scale and did some counts to calibrate it you might be more accurate, but in regard to Paul's comment, the bees during a flow might weight more on average.
Joe
Date: Tue, 19 Jul 2016 15:17:59 -0700
Date: Tue, 19 Jul 2016 15:17:59 -0700
Matthew Hennek
Jul 26, 2016, 5:18:53 PM7/26/16
to madbees
Hey Coral,
Here's some resources that might help you:
~Matt
Here's some resources that might help you:
Good info on how to do powdered sugar roll or alcohol wash. According to the UofM beelab, if performed properly the sugar roll dislodges 90-95% while the alcohol wash gets 95-100%, so fairly close. As others have said, the first shake to coat the bees needs to be gentle but the shake to get all the mites out of the jar needs some oomph (a technical term).
The MN bee lab does not recommend using mite drops onto a sticky board as a good way to measure infestation levels, however I did find a possible source for this correlation here. This is for a natural drop, not a powder sugar treated hive drop.
~Matt
On Sunday, July 17, 2016 at 8:52:09 PM UTC-5, Coral wrote:
James
Jul 27, 2016, 1:57:49 AM7/27/16
to madbees
I don't do might counts. You might come up with a number that reflects reality, or you might not. And you might make a tragic decision based on it. I just tear open drone cells anytime I go into a hive. Its hard not to. You'll see a lot of them if you got them bad, and then you'll know you've got a problem that you're going to treat anyways come September. So what good is counting them? Some folks won't treat until a numerical threshold is passed, but really...You're going to kick yourself all winter for not treating. And they you''ll kick yourself the entire next year when your hive dies. You're beekeepers. Not mite keepers.
On Sunday, July 17, 2016 at 8:52:09 PM UTC-5, Coral wrote:
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