Well, there’s good news and there’s bad news.
Just under a week ago on a beautiful sunny, warm day (do you remember it? It was one of only two so far this year) I had the pleasure of visiting our five hives to check on stores (plenty) and to pop clean boards under the mesh floors. This is one of the better ways of guess-timating varroa mite levels in the hive. Essentially one counts the number of mites that fall onto the board over a five to seven day period and divide by the number of days. With reference to a table compiled by FERA (the food and environment research agency) showing the critical numbers of mites dropping per day it is easy to judge whether or not treatment is required.
So – the good news is that three hives had absolutely no mites on their boards at all, while one had an average drop of 1.6 mites, which is OK for now. The bad news is that the other hive had an average mite drop of 6 mites a day. I think we will have to take action, but can’t do anything until it warms up a little as there should now be brood in the hive. Interestingly (although not perhaps surprisingly), this last hive was the one I found difficult to treat with oxalic acid earlier in the year.
Lots of other ‘stuff’ was also on the boards, most notably yellow pollen (seen being taken in by the bees last week) and white wax scales.