It's interesting that I had the same Mite counts as you indicated using Apiguard in August (actually worse >40/300). I then went to OA vapor every 6-7 days. I just completed my 4th treatment last week. I did not do a mite check after every treatment (don't want to kill to many) but I do monitor the IPM board for the number of mites. After the first OA treatment I noted hundreds of mites on the board. On each successive treatment I noted a SIGNIFICENT reduction in the number of mites on the board. With the 4th treatment I maybe only saw 7 mites on the board. In the coming weeks, when the weather is warm again. I will do a alcohol wash to see how effective this has been. Dave Schultz and did a visual inspection of this hive last week and the bees looked very healthy.