I treated 7 hives with formic acid in the form of MiteAway Quick Stripes. I was worried about queen loss as some have experienced so changed 6 of the bottom boards from 3/8 opening to 3/4 inch openings. on the two hives that I may be raising more queens from I also set back the second brood chamber 3/4 of an inch to add more ventilation. All hives were given a mite count between 0 and 20 days before the treatment which is how I determined that they required treatment. I used a treatment threshold of 2%. The mite count was as follows in percent bees with mites.
Date 4/6/14 H3 2.3%
Date 4/9/14 LR5 6.3%, LR12 5%
Date 4/16/14 HS4 2.3%, HS10 8.3%, HS14 2.6%, HS15 3.6%