>> >NMD is a non-invasive, passive method which requires little effort and
>> yields meaningful results, even beyond mite population dynamics.

> For outyards, the two necessary trips are a killer.

I guess a lot depends on the assumptions--  and the particular circumstances.

In my experience, alcohol wash is slow and requires a lot of work if the frames are hard to remove or there are heavy boxes on or if the brood has reduced to a few frames in the bottom.  Although it can be very reliable in some circumstances and times of year, it can be quite unreliable in other circumstances. It requires a capable and informed operator and ideal weather. Alcohol wash is awkward -- and almost impossible when hives are huge, mean or loaded with honey.

Some of us have a strong aversion to drowning bees in alcohol and hate to see them die even if we know it is "For The Greater Good", it feels all wrong.  For that reason alone,many of us are reluctant to do the necessary tests.

The process is far less invasive and the risk of killing queens is nil, while with alcohol, there is always that very real risk.

As for practicality and time factors, I can do many more yards per day with mite drops than with alcohol wash if the yards are not too far apart and if no assistance is at hand.   Granted, it akes towo trips, but they are quick in and out visits.  If I drive a Smart Car or motorcycle, the cost of fuel is low. There is not much to carry.  On the other hand the supplies for alcohol wash are heavy, bulky, and toxic. 

I have been stymied for weeks on end by weather and by waiting for hives to have stacks of supers removed when wanting to do alcohol wash -- most beekeepers hate to have their hives opened in foul weather -- and yet I could have done the whole job easily in almost any weather with mite drops.  Snow, which we can get any month of the year, is not even an impediment, assuming one can get into the yard.

With alcohol wash, one is forced to remove frames and any beekeeper with any talent at all is likely to spot brood problems.  Some of these problems -- queenlessness and the sort -- can be seen from mite drop boards by an observant operator, however.

During my years as a commercial operator, I routinely sampled yards using only mite drops and hired college kids to do the rounds.  As I say, I was able to keep tabs on varroa and never had a problem as long as I practiced the drops.   We had a good ongoing mite profile at all times for low cost.

Our system was not elaborate and is shown on my site.  Basically, we took sheets of white plastic foundation and cut sheets of hardware cloth (less than 5-mesh) to fit and bent it so that it stood up off the foundation 1/4" and held the assembly together with two big elastics.   Later on we used sheets of Coroplast the same size and added pull tabs of duct tape.  We sprayed the boards with Pam cooking spray before pushing them into the entrance.

The hive number was written on the tab when they were pulled from the hive and the stack brought home by the kids. Some kids were good enough to do the analysis in the yard.  Some not.

The boards stayed in from the time we placed them to whenever we got back and that timespan varied a bit, but was usually about a week. We kept track of the days, since that number was used to divide the numbers we counted, when we bothered to count. We ofetn did not count mites unless there were very few, but often just estimated by grade -- good, bad and "holy shyte!.  The details fade in my memory now, but it was dead simple and fun for the kids since all they did was drive around the country and visit beautiful picnic spots for a few minutes and then carry on.

We sampled four hives per yard of 24 to 40 hives.  That is less than theoretically ideal, but was a good enough compromise.  

As for alcohol wash, it is a lot of work and not always possible to do when it should be done.  Drops are not always easily done either and that is a subject of another future post.  For drops, the hive entrances must be sufficiently large and free of crud and the bottom frames cannot have too many was protrusions on the bottom or hives must have a special bottom like the Apinovar.

Some insist that the drop boards must be full-width, and I suppose for scientific precision, that is to be preferred, but in our case, where clusters are usually centred and we don't care about the fine details, the narrower boards did the job.

I see Bill Ruzicka reched much the same conclusions about sampling as I did.  I was not as fussy about the timing, and I used different control methods, but he is probably right about that detail and apparently his method works.  I never have tried it since I never figured out how it would work in my management scheme.  Maybe I should have.

Bill sent me a DVD some time back and I have not gotten around to finish watching it.  As a rule, I am reluctant to watch videos or TV or anything that delivers information in a serial access fashion that is difficult to skim, but I am making an exception here and so far would recommend it.   He says it is 45 minutes long and there is a long lead-in.  So far I'm about halfway through and into the good part   Maybe he will upload it to YouTube.  Maybe it is already there.  Dunno.  Anyhow, I think many, if not most on the list would find it worthwhile, and a better use of time than many bee movies.  (I was about to name some, but thought better).  At any rate, I'm sure Bill will have more to say and probably has a stack of them.  He wants $15 for them and considering the bother of packaging and sending them out, not to mention production cost, that is fair.

Anyhow, Having practised both alcohol wash and mite drop, I have to agree that each has its strengths and each its drawbacks.

Personally, though, for simple varroa estimation, I prefer the drops.  For lab sample collection, archiving material, and looking for brood disease, alcohol wash is superior.

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