I think it fair to say that since the arrival of varroa in the U.S the parasite, the associated viruses and our approach has changed. At the start, many beekeepers claimed they didn’t have varroa in their colonies, simply because they couldn’t see mites, but that’s not surprising, as many can’t see queens that are many times larger! Those beekeepers soon lost their bees, decided they couldn’t cope with it and gave up. Those who did something used hard chemicals, that although caused problems in other areas, if used regularly, controlled varroa quite well – that is until the varroa built up resistance.
We now use much softer options, although they are not as effective as the harder chemicals were. If used on a regular basis, together with monitoring, they are quite effective. There are some beekeepers who don’t treat for varroa at all and claim to have few problems. I don’t disbelieve them, but I would like to see more evidence.
In the last couple of years (2015/16) monitored mite levels seem to be all over the place, where previously they were consistent. I don’t know the reason, but it is now quite noticeable. I am looking at using management techniques that I hope will help to reduce the level of mites in colonies.