Probably no resistance
I've had my chat with an expert about what might have happened to my colony that is being decimated by varroa. Here's our best guess:
The Apistan that I put into the colony on the Sunday would kill varroa on the bees very quickly. So by the time I arrived with the resistance test kit on Wednesday, the varroa on bees would have been mostly dispatched. The bees I sampled therefore had no varroa drop following the four hour pyrethroid test. The fact that only one varroa was found in the wash-out suggest that resistance is not an issue (yet!).
So why did that colony show signs of collapse? The colony (one of two then in the apiary) was treated with Apistan last September (as usual) and I wouldn't have expected a problem this year especially as the colony is quite some way from other permanent apiaries.
However, a local farmer planted borage about 3km from the apiary and the bees loved it. Two semi-commercial beekeepers spotted the borage and moved some colonies into temporary apiaries near the crop. The suspicion is that there was robbing by or of my colony and a significant exchange of varroa -- ie the excess of varroa may well have come from the colonies of the “visiting” bees. Why only one of my colonies was affected is a mystery -- but a mystery that is frequently encountered when individual colonies are decimated by varroa.
Of course little of this is certain, but it's a best-guess.
The Apistan that I put into the colony on the Sunday would kill varroa on the bees very quickly. So by the time I arrived with the resistance test kit on Wednesday, the varroa on bees would have been mostly dispatched. The bees I sampled therefore had no varroa drop following the four hour pyrethroid test. The fact that only one varroa was found in the wash-out suggest that resistance is not an issue (yet!).
So why did that colony show signs of collapse? The colony (one of two then in the apiary) was treated with Apistan last September (as usual) and I wouldn't have expected a problem this year especially as the colony is quite some way from other permanent apiaries.
However, a local farmer planted borage about 3km from the apiary and the bees loved it. Two semi-commercial beekeepers spotted the borage and moved some colonies into temporary apiaries near the crop. The suspicion is that there was robbing by or of my colony and a significant exchange of varroa -- ie the excess of varroa may well have come from the colonies of the “visiting” bees. Why only one of my colonies was affected is a mystery -- but a mystery that is frequently encountered when individual colonies are decimated by varroa.
Of course little of this is certain, but it's a best-guess.
Labels: honeybee health, varroa
posted by Turlough | 12:52
1 Comments:
Very sorry to hear of your mite problem. I'm sure your blogs notes on the problem with be of use to other beekeepers.
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