Since the arrival of varroa in the U.S there have been a number of approaches to deal with it. These have varied from the use of hard chemicals to doing absolutely nothing. There have been variations of success claimed, very often biased towards the view and approach of the beekeeper. There has also been much discrediting of other views, especially when “softer” techniques have been advocated.
I have tried to keep an open mind, but based my opinion and approach on having enough knowledge to work out what each method is trying to achieve. Some methods seem very complicated and labour intensive, which may discourage beekeepers especially beginners and those with a lot of colonies from using them. I believe that if we are to encourage beekeepers to control varroa we need to suggest reasonably simple methods.
One method that appeals to me is the artificial swarm. This can be performed without the colony making preparations to swarm. It is only a slight modification from a manipulation that many beekeepers are familiar with, so there is not much more to learn.
I will briefly describe the method below.
Place the parent colony several feet away. This does not have to be in swarming mode, but needs to be a full colony. This should be done on a fine day when the bees are flying well.
On the old stand place a floor and brood box, preferably full of drawn comb. Foundation will do, but there is more chance of absconding and the colony will build up slower. Some beekeepers place a queen excluder (queen includer) under the brood box for a few days to prevent absconding, but it can become clogged with drones. Clipping the queens wing is an alternative, although you may have to look outside for her and the bees.
Put the queen on her own in the new box. She can be caged with attendants for a short time until there are enough bees to look after her.
Remove all Q/Cs (if any) from the parent colony.
If you put a super from the parent colony onto the new colony shake the bees out of it in front of the parent colony. Close up both colonies in the same way as you would a standard artificial swarm.
When all the brood has emerged in the parent colony all the varroa should be on the adult bees. At this point two frames of unsealed brood that has about 2-3 days to go before the oldest is sealed should be placed in the brood box of the parent colony. This is to attract mites. When these frames are fully sealed they are removed and placed in a freezer for a week or so, or destroyed. This part is crucial and the key to the whole operation. To allow these frames to emerge will be disastrous. These frames should be drawn comb, preferably drone, placed in the centre of the brood nest of a full colony. The queen in a strong colony will lay up a frame in 1-2 days, so it is of similar age. If it is foundation, the age will vary considerably, depending on whether there is a nectar flow or not. Some use the new colony for providing these frames, but this will retard build – up.
At some stage a Q/C should be placed in the parent colony, but the new queen should not be laying when the two frames of unsealed brood are inserted. You need to do this to suit your own circumstances and whatever Q/Cs are available.
When the frames containing varroa have been removed, the beekeeper can do several things with the parent colony including using it for increase, removing old/poor combs and uniting back to the new colony.
This method is good for the amateur beekeeper with a few colonies. If an artificial swarm is performed for swarm control it can easily be adapted. As always, I suggest understanding what you are doing, rather than simply “beekeeping by numbers”. You must know the life cycles of bees and varroa as a minimum.