Varroa

[Benjamin moody]

Hi guys,

Does every hive in the UK have varroa present? Or is it only the hives infected?

Thanks!

[Chrisbarlow]

varroa is endemic across th UK, the majority of hives in the UK will have some level of varroa in them. There will be exceptions where you get areas isolated by geography like areas in the Highlands and Islands of Scotland. Colonsay for example. see http://www.snhbs.scot/colonsay/ or Ardnamurchan from memory I believe is varroa free.

[AdamD]

It's fair to assume that all colonies have varroa to some degree - except the locations that Chris mentions.

Beekeepers can sometimes be surprised by how many varroa there are in a colony which they only see after treating to remove them.

[Chrisbarlow]

even people who go "treatment free" accept they have varroa at some level at all times.

[Steve (The Drone)]

I had a colony that appeared almost varroa free. By monitoring the drop and using the official formula I should not have needed to treat. We did a quick vape and had a drop of about 1000. I don’t count them anymore- just kill them. I always assume the beasties are in there.
Steve.

[NigelP]

Sadly this all too true. Drop counts are a waste of time; they do not accurately reflect the population of mites.
I had very similar to you Steve, very few dropped over a week..technically no need to treat.
There was still over a thousand mites dropping after the third vaporization.
A lot of people lost a lot of colonies last year using that varroa calculator on the NBU site...it should be taken off line before anyone else loses theirs.

[Jim Norfolk]

Mite drop counts work for me. It would be interesting to compare methodology. For example do all types of mesh floor work. I use simple plastic coated wire mesh and the mites have a drop of a couple of inches onto the board, with no prospect of climbing back up. I do not use sticky boards. Counting every day is preferable but two or three days is OK, any more and mites can be lost in debris and need washing out to count.

The counts also need to be carried out over at least a brood cycle since they reflect the mites in emerging brood and fluctuate quite a lot. If the counts are suspect I confirm them with icing sugar. The correleation between icing sugar count and mite drop is quite good but there are outliers.

[thewoodgatherer]

I have made the mistake of using a none sticky board and thinking varroa levels are low, once some oil is applied and the check repeated the count has gone up considerably. I think if people fit them dry and come back a week later most of the mites may well have just walked off the edge.

[Chrisbarlow]

I just treat regardless. I treat apiaries not colonies. If one colony in an apiary is treated then they are all treated. I treat autumn, spring and mid winter. If varroa are low on a colony then disease is much more likely to be low and this increases the odds a colony will survive winter.

[NigelP]

Mite drop counts work for me.

In what way do they work Jim? Are your drop counts giving you an accurate reflection of the total population? And how are you assessing that total population?
The only way to really assess this is by alcohol washes and estimating your total number of bees...not an easy figure to be accurate about.
I've found that daily inspection for a week on Thornes/home made mesh floors/Paynes poly hive mesh floors/Abelo poly hive mesh floors bear no resemblance to the drop I see 48 hours after vaping Apibioxal.

In fact I have just finished the 4th vape on a colony that dropped over 2000+ 1st vape, 2000+ second vape, 500+ on the 3rd vape...now down to about a 100+...
1 week of observation on drops before vaping showed three mites.

Certainly with the bees I keep drop counts do not tell an accurate story.