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Hi folks,

I was wondering what you all consider "acceptable" when it comes to mite drop numbers in a deep hive body, specifically 8 frame. There is so much info out there regarding this topic that it constantly varies. I don't expect much different here, except that you can say/ explain why you accept a given number. Stating what you see as acceptable and the type of test you use and prefer would be most appreciated. Thanks!
 

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There are so many variables, depending on the time of year and hive population, that it's nearly impossible to cite specific numbers that are acceptable. Take a few minutes and read through the following link at Randy Oliver's site. His information would be the best recommendation I know of to accurately monitor mite counts.

http://scientificbeekeeping.com/fighting-varroa-reconnaissance-mite-sampling/
 

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Lol, I have read his work until my retinas started burning. Great info there, but just like you, he doesn't set a particular number either. My numbers are below the examples he gives for thresholds, but I was just curious what numbers other folks are using. Thanks though.
 

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I've read a study showing that the important mite readings are the ones taken late August/early/September. As the mite count rises above 5%, the less chance they have of making it.
 

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, but I was just curious what numbers other folks are using.
I like to do 24 hour sticky board counts in early spring, early summer, fall, and early winter. This gives me a pretty good overview of mite build up throughout the year. Spring and early Summer I usually see just a hand full of mites in 24 hours. When we reach Fall it could be up to 30+ mites. For me, that's the trigger to treat, which usually happens every year. Others may find that number acceptable and not treat.

A lot depends on the size of the colony. If there are 30 mites dropped on a relatively small colony, they are probably in serious trouble. On a boomer, maybe not.
 

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University of Fl recommends treating at 60 on a sticky board 24hr drop or 17 for a sugar shake or ether roll. But, those numbers are for summer or fall thresholds. I would not want to see numbers half of that this time of year. You want them to start off in the spring with low counts if the counts are borderline high now they will be sky high by the time you pull your supers this summer. That's my take on things.
 

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I am a hard-nose when it comes to mites. My rule of thumb is a sugar shake monthly starting in June. If I find any mites at all, I do powdered sugar dusting (3 x a week for 2 weeks). Late in the year I do a final shake using a really big sample (about 2 cups of bees) and again if I find any mites at all, I treat but with OA. If the same hive seems to keep having problems, I replace that queen and get rid of her drones.

My own reasoning is that mites carry viruses, so any mites at all are unacceptable. It seems like most hive problems have mites involved somehow. Before I introduced VSH, I saw a lot more mites and would tolerate counts of up to 15. That changed when I got some VSH in there. However, I am a hobbyist so I can afford to be a hard-nose about it. After all, I'm not dealing with dozens of hives here.

JMO

Rusty
 

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sample sample sample some more. Drop rates fluctuate immensely. I would sample every day over a week. Or a week over a month. One mite count will not catch the variation across the bell curve.
 

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I agree with burns375, I think more or less contant sampling is exponentially more effective at monitoring than any one-off per season testing, of any kind.

That's one of the reasons I am so sold on sticky boards -- because sampling using that method causes no disruption to the bees' lives at all, and very little effort on the part of beekeepers, either. All it takes is a beeks' determination to do it. And if you set up your equipment correctly, pulling the boards can even be done in the dark when you get home from work.

And since it takes no skills beyond spreading cooking oil on a sheet of plastic and then picking up the mites that fall and arranging them in groups of five for easy counting, anyone can do it. And I think this is particularly important for new beekeepers who are just getting used to handling bees. Digging into your hives enough to collect the right bees for doing any of the roll-type testing, requires suiting up, lighting your smoker, smushing some bees, etc. The result is that it isn't done as often as needed, or even at all, like it ought to be. So vital information is not known until a dead-out makes the point irrefutable.

In answer to the OPs question: Last summer I used the numbers published by NY BeeWellness and the similar Canadian sources, since I am in northern NY. IIRC, NYBeeWellness had a late summer/fall need-to-treat threshold of 20 mites/day and the Canadian one uses 12 mites/ per day. My counts were in the single digits all summer until (in the first week of Sept.) one of my hives produced 15 mites/day, repeated over several days. I treated that one. About ten days or so later another one spiked so I started to treat that one, too. My third hive stayed below the threshholds so I did not treat it. The first hive treated got a full dose of Apiguard, but the latter one only got a half-period treatment because temps got too low to continue before it was done.

I have continued to monitor since then, including all winter even though there are no published mite/day thresholds for the broodless period of a deep northern winter. (For curious minds, the fully treated hive's long term winter average is less than 3 mites per day, the half-treated one's average is less than 1 mite/day and the untreated one's average is 0.3 mites per day.) In the winter some of my test periods have been 30 days long because it is a such pain to unwrap the insulation layers to access the sticky board slots. But whenever I have the panels off, I pull and count. Next year's insulation arrangements will allow regular monitoring, because I think it's interesting, and potentially useful. In the next month when I will start to remove some of the outer layers of my extreme-climate insulation, I will once again start regular, even daily counts.

Oh, and, one other thing about sticky boards, aside from actually doing the counts, the other critical thing is: You have to record your numbers. Because you won't remember what they were. Most of the value of the information you are collecting is the change over time, not the actual number, or treatment threshhold. I'm terrible about recording data, so this is the hardest part for me.

Enj.
 
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