Kathy, last year was the first year that I actually counted mites. I have to get this story clear on what happend with me, I will be brief.
2005 -- got 4 package colonies, did not do any mite counting that year or the following year
2006 -- All colonies collapsed and died in the fall (except one little tiny teeny colony, which was the result of a split), a direct result of mite neglect, I had treated with formic acid in this fall (2006), but the damage was so great the colonies still collapsed
2007 -- had an overwintered tiny colony, did not do any mite counts until after the packages and nucs arrived
2007 -- bought 4 nucs and 4 packaged bees, did a mite count on all 9 colonies, a few mites
2007 -- after finding a few mites did a few powdered sugar treatments
2007 -- monitored mites, still had a few mites
2007 -- fall, monitored mites, about 2-15 per colony
2007 -- fall, vapourized using Oxalic Acid
2007 -- did three series of mite counts, each from 48 hours after, 2 weeks to 1-1/2 months apart
Please note, all these dates and amounts are just from the top of my head, I have intricate details in my records, but these are enough to show cause and effect
After the vapourization there was extremely high levels of mite deaths, even after the 1-1/2 month period. I was shocked at the numbers. After the 24 hour period, most colonies showed several hundred dead varroa. I know this first hand, as I took out the boards and counted the mites and as the sticky board tests showed, the mites continued to fall for over a month and a half. I did no further mite counting. Some may say that mite counting is redundant and a waste of time, but I am a record keeper, and these exercises of counting mites gave me a very intricate idea of what was going on with my colonies and how many mites were really present, it was shocking to say the very least.
During my deep spring inspection when I come back from Vegas, the weather will be very conducive to a deep check by then. After this deep spring check I will perform another three day sticky board test to ascertain if there are any mites present. We will see, and time will tell that tale.
In my second year of beekeeping when I had total collapse of 9 colonies I was devastated. I had worked very hard with the bees and seriously never understood the magnitude of damage that lack of mite controls could possibly cause, be it whatever means that any beekeeper does for mite control. There are so many measures for mite control, they have been discussed time and time again here. That goes from the thoughts of small cell bees, hygienic bees, and so on and so on and so on.
I just know that I really don't ever want to lose that many colonies again from such an evil as the varroa destructor. Enough said. Have a wonderful and greatest of these days, Cindi