The trouble with taking notes during a lecture is that while you’re scribbling the speaker has moved on so my jottings aren’t too thorough.
The first speaker was Prof Tom Seeley on the subject of how a swarm chooses its future home. Tom was concentrating on when a swarm has left the hive but my own experience suggests that bees start looking for potential sites weeks before they even start queen cells.
About 3% – 5% of the bees in the swarm form a ‘search committee’. Then they dance on the surface of the swarm. Disagreements are sorted by head butting and buzzing other dancers.
I once watched bees dancing on a swarm and, using my shadow for guidance, was able to predict accurately in which direction the swarm would go.
The next speaker was Prof. Francis Ratnieks of LASI on the Sussex Plan for Honey Bee Health and Well Being: Controlling Honey Bee Diseases, primarily Varroa. Apistan still works at a kill rate of about 68% in colonies that haven’t been treated with it for 5 years but at only 33% in hives that were treated with it 4 months previously. In summary, forget it!
Oxalic acid is better and Francis described the various ways of applying it: dribbling, spraying and sublimation/vapourisation. Sublimation with a dose of 2 grammes of oxalic is best as it kills mites but doesn’t harm the bees.
Timing is very important as there must be no sealed brood in the hive. Two treatments 10 days apart will kill 99.5% of the mites. December is the month when there’s least brood. Hives should be checked before treatment and any capped brood removed. A small patch matters! There’s more information on the LASI website.
Hygienic behaviour is worth selecting for as it slows down growth in Varroa numbers. It’s also effective against AFB and chalkbrood. A colony with lots of bees showing signs of Deformed Wing Virus is on its last legs (or wings!).
Drone brood removal probably isn’t worth bothering with. The recommendation is integrated control through oxalic and hygienic selection.