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Cathryn

Varroa

One of my friends has circulated a warning as he has seen an unexpected rise in the numbers of varroa. Possibly not that surprising, if bees have done well this year then so must their parasites. I've not yet checked my hives but I have been doing some reading on the effectiveness of dusting with icing sugar and the only research based work I can find says it doesn't appear to have any real effect.

Can anyone highlight some different research work on this?
Lorrainelovesplants

The icing sugar thing really depends on whether your bees self groom.

Ive started using a correx tray(wiped with a smear of veg oil) during season, and use it to check the number of mites. In the aftermath of dusting with icing sugar Ive noticed much more mites - therefore my bees are grooming - therefore its working.

I also use varroa gard dusted as a treatment before using apigard at end of season.
Cathryn

I understand the principle but this, for example, is similar to most of the conclusions that I have read.

http://www.ent.uga.edu/bees/personnel/documents/RevisitingPowderedSugar-JAR51414.pdf
Lorrainelovesplants

There is anecdotal evidence that not all honey bees groom. There is some specific breeding in West Cornwall to encourage self grooming bees - perhaps Tavascarrow has more info on this?
joanne

When I had my bee's they groomed as I would get a bigger drop after dusting.

However if you are in topbars or Warré or any of the other alternative hive methods, the likelihood that you've got significant numbers of varroa decreases as the bee's are self determining the size of the brood cells by instinct they tend to make smaller cells which means the varroa doesn't breed in the same way as they can't co-habit during bee development.

I have always worked on the principle that less is more and tended to go for a thymol treatment in Autumn rather than sticking loads of icing sugar all over my bee's
Tavascarow

Most conventional beekeepers use oxalic acid in the winter &/or thymol in the spring & autumn, they only use icing sugar as a monitoring tool. There is no doubt that it has an effect, but whether that is sufficient to cure a badly infested colony is doubtful IMHO.
If your bees have a degree of resistance anyway then regular icing sugar treatments might be sufficient, only trial & close monitoring will answer that.
So my advice would be use it, keep an eye on the number of varroa dropping & the general health of the colony & be prepared to use something stronger if needs be.
Smile
dangerous

Re: Varroa

One of my friends has circulated a warning as he has seen an unexpected rise in the numbers of varroa.


Infestation in large established colonies is very significant this year according to NBU.
Beware of relying on natural mite drop or the Beebase varroa calculator as indicators of numbers of mites.
One of my colonies on 14 x 12 with a natural drop of less than 5 a day in September, when brood numbers are decreasing and you would expect a higher proportion of phoretic mites, has dropped approximately 4,000 mites during three weeks of Apilife. Many of my friends are reporting similar.
As an aside there is little to support the protective effects of sugar dusting and small cell size.
Varroa was not a problem last year...many have become complacent.
A good ongoing IPM which can include sugar dusting/drone culling/chemical control should keep on top of things.
Cathryn

Sad That's worrying although mine are new colonies. The bee inspector visited just after I had removed a varroa board with very little on it. He was happy with what he saw and I didn't do another treatment. I hope he was right.
Mistress Rose

The mild winter last year probably didn't help.
dangerous

I will oxalic in the winter to mop up.
I'm looking into vaporising which looks much less "upsetting" for the bees than opening up and dousing them with syrup.
Cathryn

Well I've just treated mine with oxalic acid. I didn't disturb them much, those in the topbar barely noticed me. Maybe as I become more confident I will treat them differently but for now I am thrilled that they are doing well. I did put fondant on them a month or so ago which has been more or less ignored by those in the topbar. Clearly I am overwintering several mice though. Rolling Eyes
sean

They're probably ones from your house using it as a holiday cottage.
Cathryn

Well, touch wood and all that...
Mistress Rose

I don't know much about top bar hives, but in 'conventional' hives it is usual to put a mouse guard on the entrance in the autumn. My stop your little friends using it as a winter holiday cottage. Laughing
Tavascarow

You may find the bees will have killed them by spring. I haven't treated any hives since last spring.
They where hail & hearty at the end of the summer so I will treat with thymol once the weather has warmed.
BahamaMama

Saturday was cold, gray and windy here (SE) but I took the top off the hive, slipped another bag of fondant in and closed up. I saw no signs of activity at all. We then spent the afternoon at our local apiary hefting, maintenance and feeding and saw quite a lot of bee activity. I started to worry.

This morning was dry, clear and bright, much warmer than recently and no wind, still no bees and I convinced myself I had lost them. An hour later the hive was covered in sunbathing and buzzing bees. They looked happy and were flying well, I am so relieved and so happy they are still here. I could never have imagined being so upset about insects Very Happy
Cathryn

I am always very relieved to see mine. Smile Can't understand how I can be so absorbed watching tiny insects flying in and out of a hole.
Mistress Rose

Our bees by the house were flying yesterday. Probably cleansing flights after having been huddled up in the hive to keep warm over the last week or so.
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