Varroa mite counting, round 4.

On 8/3/2013 at 1310, I removed the sticky board from beneath each hive.  The boards had been in for about 2.5 days.  Unfortunately, I lost track of specifically when I placed the boards.

Hive A had 17 - 19 mites on the board.  When I removed the boards, I scraped off some Vaseline and (likely) mites.  So, I estimated the number of mites that might have been in the ninth of the board to be 3 instead of the 1 that I counted.  Hence, I'm going to go with the higher number.

Hive B had 33 mites on the board.  One reference that I recall said that greater than 40 mite (in one day, mind you) was another indication for treatment.  I'm still below that number, at least.  In any event, I continue with the mites per 1,000 bees per day calculations below.

On 6/16/2013, Hive A had a population of about 9,375 bees (7.5 frames full of bees x 1,250 bees per full frame).  On the same date, Hive B had a population of about 12,500 bees (10 frames full of bees x 1,250 bees per full frame).  Again, we are going to say that this is over 4 days of collection.

• Hive A:  1 mite per 9,375 bees per 4 days = 1/(9,375 x 4) = 0.03 mites per 1,000 bees per day.
• Hive B:  10 mites per 12.5k bees per 4 days = (1/12,500 x 4) = 0.2 mites per 1,000 bees per day.

So, from the numbers above, I feel that I am comfortable not treating for mites at this time.  The quote that I am following, you might recall, is the following:  "If your sticky board count shows more than 2 mites per thousand bees per day in mid-August or more than 4 mites per thousand bees per day in September, you should find a way to reduce the mite population."

Even if the boards were only in for one day--and thus the mite numbers would be 0.12 and 0.8 mites per thousand bees per day--there would not be a clear indication to treat.

After this mite count, I did not get to a mite count for over a month.  I did an about 2.5-day mite count that ended on 8/3/2013.  There were significantly more mites, but there were also significantly more bees.  I'm hoping to do an inspection over the weekend of 8/3/2013 so that I can get a good estimate of numbers of bees.

Varroa mite counting, round 3.

On 6/20/2013 (this makes this post somewhat out of order), I removed the sticky board from beneath each hive.  The boards had been in for about 4 days.  Unfortunately, I lost track of when I placed the boards, but I did note that I removed them on 6/20/2013 at 1750.

Hive A had only 1 mite on the board.  Hive B had 10 mites on the board.  On 6/16/2013, Hive A had a population of about 9,375 bees (7.5 frames full of bees x 1,250 bees per full frame).  On the same date, Hive B had a population of about 12,500 bees (10 frames full of bees x 1,250 bees per full frame).  Again, we are going to say that this is over 4 days of collection.

• Hive A:  1 mite per 9,375 bees per 4 days = 1/(9,375 x 4) = 0.03 mites per 1,000 bees per day.
• Hive B:  10 mites per 12.5k bees per 4 days = (1/12,500 x 4) = 0.2 mites per 1,000 bees per day.

So, from the numbers above, I feel that I am comfortable not treating for mites at this time.  The quote that I am following, you might recall, is the following:  "If your sticky board count shows more than 2 mites per thousand bees per day in mid-August or more than 4 mites per thousand bees per day in September, you should find a way to reduce the mite population."

Even if the boards were only in for one day--and thus the mite numbers would be 0.12 and 0.8 mites per thousand bees per day--there would not be a clear indication to treat.

After this mite count, I did not get to a mite count for over a month.  I did an about 2.5-day mite count that ended on 8/3/2013.  There were significantly more mites, but there were also significantly more bees.  I'm hoping to do an inspection over the weekend of 8/3/2013 so that I can get a good estimate of numbers of bees.

Screened bottom boards.

During the third inspection, I installed screened bottom boards in each hive.  This is part of IPM or "Integrated Pest Management."  I'll describe each in this post.  In this post, I describe the next step that I take to monitor for bee pests.  If you'd like to just skip to the video, click here.  There will be another link at the end of this post.

First, a standard bottom board (non-screened) is little more than a piece of sturdy wood with edges around three of the four sides.  It is the bottom-most part of the hive.  These edges hold up the rest of the hive, and they also allow a space for the bees to crawl across at the bottom of the hive after they enter.  I don't have a picture of my own bottom boards, but here is a good image of one.  The picture is attributed to this address.

A hive's bottom board.

Above, painted white is a bottom board.  The raised edges that you can see along the back and on the left and right edges hold up the hive bodies that are above it.  The gap in the front, where the bottom board lacks an edge or ridge, will make a wide hole through which bees enter and exit the hive.  The wood "stick" that you can see is the entrance reducer.  That is used to make the opening smaller during certain seasons or when the hive population is too low to need or be able to defend the larger opening.

Almost all honeybees have to contend with the Varroa destructor mite.  The image below is attributed to this address.

A tick is to a human as a mite is to a honeybee.

The following picture is not one of mine.  Its attribution is here.  But, it shows nicely how the mite attaches to a bee.

The mite is attached to a honeybee's thorax.

In daily living and grooming, these mites will occasionally fall off the bees.  If you are using a standard bottom board, the mites will land on that.  They don't die from the fall.  They will crawl around on the surface of the bottom board until a bee goes past them that they can grab onto in order to parasitize.

If, however, you use a screened bottom board (picture attributed to this site)...

A screened bottom board.

...a portion of the mites will fall through the screen.  It will be hard for them to travel the distance needed to get back to the area of the bees and re-attach to one of them.

Moreover, if you have a layer of plastic underneath the screen and it is covered with something sticky or oily, the mites will be trapped.  This will help in two ways:  (1) The mites cannot get back onto a bee to suck their hemolymph and eventually reproduce, and (2) The mites can be counted to monitor the infestation level of the hive.

In this video, I install a sticky board under each screened bottom board under each hive.  Hive A gets one with an insert under the screen that is covered with Vaseline only along the periphery.  Hive B gets one with an insert that is fully covered with Vaseline.