How's your VARROA???

[Hugh]

This is the High point in the season for Varroa population increase, just as the bees start to decline.
So, how bad is your hive:confused::confused:

Has this been a good year or a bad year for you and which methods of control have you used or are thinking of using :confused::confused:

[gavin]

Hi Hugh

It has been an odd year for me as I'm largely building back up from a low base. Varroa are generally bad in the most powerful colonies, and mine haven't been in that state this year. However I did start the year with a serious Varroa problem in my survivor colony. A spring Apiguard treatment seems to have kept it in check, and in all the other colonies a break in brood raising plus the subsequent lack of drone brood in particular has greatly helped as it always does.

So now my colonies all seem relatively free of Varroa, but I'm sure that they are there. Have seen very few on the mesh floor insert lately. I'll probably use a thymol method soon, then the usual oxalic treatment - this time aiming for December rather than January.

best wishes

Gavin

[Jimbo]

Hi Hugh,

I have varroa but I never seen to get a serious varroa problem. Again this year I have seen no varroa when uncapping drone brood. I mix and match my treatments each year. last year I used Apistan strips at the end of Sept and oxalic acid (trickle method) in Jan. This year I intend to use Apiguard in the next week or two as it requires warm temperatures to work effectively and oxalic acid again in the winter. For checking how effective the treatments have worked I place inserts into my open mesh floors during treatments. To make the varroa count easy I scrape the floor droppings into a honey jar and add alcohol. If you shake the jar and let it settle the varroa will float. I pour the supernatant through a paper filter in a funnel and let the alcohol evaporate. (you can use a coffee filter paper) You can then easily count the varroa. If there is a lot of floor rubbish you can give a second wash with alcohol and you usually get a few more varroa coming off. This was the method I used years ago to check for varroa before we actually got it. I have found it quite an accurate method for counting varroa.

Jimbo

[Neils]

Hugh,

I've probably been less vigilant than I should but I've reached a stage where I really don't trust natural mite drops anymore so I've relied on drone brood uncapping and, where I've felt necessary culling which only occurred in one colony. (all three of mine are from the same parent colony this year).

I've just applied Apiguard and so will compare those numbers against what the drone uncapping suggested and see where things stand after that. I didn't treat the parent colony with oxalic acid last year and hope not to have to this year either, but we'll see.

[Calum]

been removing capped drone brood all year long.
Now treating with 60% Formic acid (6-7 applications of 2ml / frame on a foam mat -see in bee health forum (http://www.sbai.org.uk/sbai_forum/showthread.php?208-What-is-your-medicine)).
Due to the very changeable weather this is not going really well so next year I will treat with an evaporation bottle (also using formic acid).
In December I'll treat with oxalic acid in a sugar solution.

[Hugh]

The funny thing with VARROA is that most people have the problem but not many know how bad or wether they should use a treatment, or not, and which treament to use is a bit of a guessing game. I've spoken to some bee keepers that just dust with iceing sugar and remove Drone Brood without any other chemical treatments and their bees are getting on fine.

Its a pity there is not a better way to monitor the mite numbers.

[Calum]

Hi Hugh,
here is a method for ascertaining vorroa infestation levels from Germany. (http://www.sbai.org.uk/sbai_forum/entry.php?70-Varroa-Infestation-Checking-method)
Dusting with icing sugar does not help at all (that is a fact - tried and tested and failed in studies at Celle Uni).
You can get away with just removing drone brood if you have a swarm or artificial swarm - for a season, they leave the most of the varroa behind, but that wont keep a colony alive over a couple of years.
There are various treatment strategies well documented & advised here in Germany, if you follow them religiously (here) your loss rate should be well below 10%. I know intelligent beekeepers that have thought better of themselves and lost all their stocks trying out their own ideas.
That was 48 and 53 colonies in one year. I think they should be banned from keeping bees. Not treating your hives correctly is not only a death sentance for your bees, it is also promoting the spread to other colonies in the area endangering other beekeepers bees.

About 50 varroa mites in a colony untreated in Sept equates to 2000 at the end of April, as they multiply exponentially. So no wonder when a colony collapses in April or May. I am sure someone will provide more exact figures, but that is about right.

Using a treatment correctly will always do less harm than not treating at all. I assume the BBKA has a varroa handbook recommending varroa management stratagies.

[Neils]

Defra also provide a Varroa calculator that gives recommendations based on natural drop or drone uncapping numbers, time of year etc

clicky (https://secure.fera.defra.gov.uk/beebase/index.cfm?pageid=67)

[Stromnessbees]

Or might varroa-treatments soon be a thing of the past?

- http://www.dailymail.co.uk/sciencetech/article-1305695/Beekeeper-Ron-Hoskins-breeds-indestructible-bee-protect-mite.html

Good luck to Ron Hoskins anyway.

Doris

[gavin]

Yup, good stuff from Ron. Similar bees are in Scotland:

http://www.scottishferals.org.uk/

though when I tried some of John's bees in my apiary they weren't quite resistant enough to shrug off mites unaided. In fact some of the bees already in my apiary also showed some of the resistance traits.

Pete Haywood in Wales has - like John in WC Scotland - also gone cold turkey for Varroa treatments and has stocks that are doing fine on their own. Rogder Dewhurst is also doing something similar with a Cornish bee breeding group and was talking last year of doing a PhD on this.

The Russian bees in the States are the best example of Varroa-resistant bees, except of course the place they come from has resistant bees too! And Tunisia, maybe Arizona, and ....

Ron is a BIBBA man and has a separate Amm-based selection scheme going with a different collaborator. Perhaps we should be combining the two here in Scotland? Not Doris though - she'll have to sit on the sidelines until Orkney finally gets over-run by the mite!

Gavin

PS Did no one catch me on Radio Scotland at lunchtime?

[Stromnessbees]

Here's the interview with Ron Hoskins on Radio4 pm:

scroll to 49:05:
http://www.bbc.co.uk/iplayer/episode/b00tfrz7/PM_25_08_2010/

Doris