Varoa Mite Drop

[Liam C Ryan]

Is there a method of calculating the mite numbers in a hive by counting the daily mite drop .I have treated my three hives with bayvarol for the last six weeks but got very little kill so may need to treat with oxalic acid, how do I find out if I need to treat or not.
Liam C

 

[Finman]

However it is usefull to treat them. There is no harm about oxalic acid.

 

[mbc]

However it is usefull to treat them. There is no harm about oxalic acid.

Not quite the whole picture as I see it. I'm not very good at remembering references but I'm positive I've read a paper stating hives treated with oxalic in the winter were slightly smaller in the spring than those that werent.

 

[drstitson]

since many colonies may actually be rearing small quantities of brood over winter then it would be technically true that chilling a colony briefly would reduce spring numbers (by a small number).

 

[RoofTops]

There are reports of varroa resistance to Bayvoral in Ireland: http://www.irishbeekeeping.ie/beehealth/fibkavarroa.html This may explain why you have seen only a few mites being killed.

To be honest I would recommend all beekeepers to ditch these synthetic pyrethroid treatments in all but the most remote parts of the British Isles. If your mites are not resistant they soon will be.

Oxalic Acid is only effective if the bees are broodless or as broodless as possible - so this mean treating them in late December or early January for most places.

So I fear you must wait it out until the depths of winter and then apply an OA syrup trickle. Ignore the arguments above - any loss of brood due to OA treatment will be a fraction of that caused by untreated mites.

 

[itma]

Is there a method of calculating the mite numbers in a hive by counting the daily mite drop .I have treated my three hives with bayvarol for the last six weeks but got very little kill so may need to treat with oxalic acid, how do I find out if I need to treat or not.
Liam C

OK.
First, take a look at the UK Government booklet "Managing Varroa"
Its a free PDF download https://secure.fera.defra.gov.uk/beebase/downloadNews.cfm?id=93
On page 31 there is a nice simple graph relating daily natural mite deathrate (through the year) directly to how intensively you need to treat - using their mathematical model, so there's no need to develop your own!
Since you want to know their natural death rate, you don't want to be using a sticky board!

I'd be a bit suspicious about you maybe having Bayvarol-resistant mites.
This is discussed in the same booklet.
It makes sense NOT to use it routinely every year (although that is still advised in some places). See the end of page 25

Frequent treatments,
especially when misused or when treatment strips
are left in the colony for longer than
recommended, accelerate the development of
resistance.

Two other attacks that can be used on Varroa (but are not mentioned in that booklet) are Icing Sugar and "hive sanitising" dusts like 'Varroa-Gard'.
Both these treatments are not limited to being used in a specific season.
Any time you have the hive open you can dust the bees with harmless Icing Sugar, and their increased grooming causes live mites to be dislodged from adult bees. It doesn't do anything about mites on brood, so its effectiveness is more apparent when there's little brood in the hive. And you don't want to have your inspection board in - let them drop right out of the hive, without a chance of returning. (You might perhaps prefer to use a sticky board to see how many live mites have been groomed off.)

Additionally, there's a lot of support on this forum for feeding thymolated syrup as an anti-varroa action. (Search and you'll find LOTS of threads!) But its getting late in the year for syrup feeding.

 

[Arfermo]

Itma above mentions the FERA leaflet on "Managing Varroa", downloadable in pdf format only these days. In the rather thick leaflet are tables explaining what to look for in regard to mite drop and treatments throughout the year, including oxalic acid and much else. Oxalic acid although not an "approved" treatment is not banned either and anybody with a mite of common sense would treat with it whether or not there is a significant mite drop for the simple reason that varroa are there like it or not and will multiply very rapidly come spring. Getting rid of as many as possible gives bees the best chance of a viable future.
Dr Stitson seems to suggest above that only the trickle method is available. Not true. He also implies that it will harm eggs and uncapped larvae. True, but at Xmas there is very little around and not enough to destabilise the colony. I and many others I know evaporate the stuff. People then launch into tirades about how dangerous that is. Yes if you swallow or breathe it in through sheer carelessness. Bear in mind that there is a large range of garden produce which contain oxalic acid, rhubarb being the most significant.
In conlusion, if you want the best for your bees, oxalic is bordering very closely upon essential and is more effective than the Thymol treatments done in early autumn. Here endeth..................................

 

[itma]

...
Dr Stitson seems to suggest above that only the trickle method is available. Not true. ... I and many others I know evaporate the stuff. ...

The doc, though occasionally brief is, I'm sure, well aware of evaporative treatment, and I know he knows that Oxalic is one of the ingredients (along with thymol) in the hive sanitising dust that I referred to, Varroa-Gard. Its relatively new, but seemingly comes from a company with experience in poultry mites, and is claimed to be usable and effective all through the year.
There are things that can be done at this time of the year. You don't have to wait until Christmas!

Incidentally "Managing Varroa" *is* still available as hardcopy (as well as the pdf download that I linked above).
Only last night my course tutor was handing out glossy printed copies ...

The simple graph on page 31 (figure 51) should be Liam's first target, relating natural daily death rate of mites to the severity of the infestation, and he can continue from there. But the whole booklet is worth a read (its not all that long!)

 

[newportbuzz]

Oxalic acid although not an "approved" treatment is not banned either

its been aproved in ireland and the op is in tip

 

[drstitson]

"Dr Stitson seems to suggest above that only the trickle method is available. Not true. He also implies that it will harm eggs and uncapped larvae".

2 points:

1. most UK users i would imagine will be using the trickle method hence my emphasis.

2. my implication was that chilling the colony, however briefly, in the depths of winter, may lead to loss of any brood present. direct toxicity of the oxalic itself will likewise have a small effect.


re the alternative - i've no doubt the odd dose of oxalic acid vapour will be relatively harmless and also fairly effective BUT have been hearing reports of high summer losses of colonies that have bee treated every 3 days for 4-6 weeks.

 

[Finman]

re the alternative - i've no doubt the odd dose of oxalic acid vapour will be relatively harmless and also fairly effective BUT have been hearing reports of high summer losses of colonies that have bee treated every 3 days for 4-6 weeks.

OXALIC ACID VAPOUR IS NOT MENT USE LIKE THAT. It makes fine acid dust on hive surfaces.

Mite dying happens during 4 weeks when you handle them once.

FORGET SUGAR DUSTING! it is not efective. It is proved so many times with researches.

- I wonder what wisedom has "UK Covernement".Defra has published 7 years how to use OA trickling

- how many beekeepers you have still in prison after treated mites with illegal acid?

 

[drstitson]

"OXALIC ACID VAPOUR IS NOT MENT USE LIKE THAT. It makes fine acid dust on hive surfaces.

Mite dying happens during 4 weeks when you handle them once."

precisely - however the stubborn italians believe that you must keep treating until the drop ceases!!!! They also mistakenly believe that treating will somehow magically reverse the effects of DWV almost immediately!!!

 

[itma]

...
FORGET SUGAR DUSTING! it is not efective. It is proved so many times with researches.

AFAIK, its NOT VERY effective, because as stated above, it only has an effect on some of the mites on adult bees - and the large number of mites on the brood are completely untouched.
It is certainly nothing like the supposed 80%+ kill that Apiguard, pyretherins, etc SHOULD achieve.
But I don't think sugar is of zero effect, and it can be done now. With pyretheroid resistant mites, what else (beyond hive sanitisers and sugar) could be used before the Oxalic or Lactic Christmas present?
If the hive is already open, for any reason, a dusting of sugar can't do any harm, can it? And any mite population reduction (assuming a fairly large population of resistant mites) has to be better than no reduction, doesn't it?
But I hope that I've not suggested that its worth opening the hive for the single purpose of sugar dusting.

...
- I wonder what wisedom has "UK Covernement".Defra has published 7 years how to use OA trickling

- how many beekeepers you have still in prison after treated mites with illegal acid?

From the "Managing Varroa" booklet -

No mention of alternative, unauthorised,
products in this leaflet should be taken as an
endorsement of efficacy, safety, or a
recommendation to treat. They are referred to
because they are commonly available.

Isn't it a case of official recommendation (or not) rather than products being not allowed (and against the law to use)?

 

[oliver90owner]

FORGET SUGAR DUSTING! it is not efective

Agreed. Probably less good than some of the 'hive sanitisers'

SUGAR ROLLING, on the other hand, seems a much better method, combined with first capped brood culling. Certainly not an autumn/winter varroa treatment. Trouble is lots don't understand the difference and assume they are the same.

RAB

 

[Finman]

.
Best methods are thymol and formic acid in late summer.
Then trickling is only method to use in the middle of winter when brood are away.

These methods give over 95% succes rate ..... If they succeed. They do not allways succeed. That is why youd should be sharp to notice the things.

Bad problems arise if the hive has no brood brake like in New Zealand.

It seems to be allways guys which want to put his own spoon in the soup and know better the issue than a 10 years lasted researching project.

Oxalix acid fumigation is laborous and dangerous to lungs. i sprayed in a room leaf mites with 3% oxalic acid spray. Mist dryed in the air and acid dust went to my lungs. I really must quickly escape from the room. Afterwards I saw that the plant was covered with thin acid dust. So was the window. Leaf mites were gone too.

 

[Ruary]

its been aproved in ireland and the op is in tip

To be precise one named 'medicine' has only just been approved for use in Ireland. The label instructions give a dose of 61.6g of oxalic acid per litre of syrup (1 sugar to 1 water w/w).
Ruary

 

[itma]

No dispute whatsoever: Sugar dust can only impact the mites on adult bees (which are a fraction of the mite population except when the colony is broodless in midwinter).

It is not being suggested that sugar dusting is a substitute for 'proper' varroacides, merely that it could be helpful in reducing the varroa population, right now, to the benefit of the bees - rather than doing nothing until Christmas.
IF you have the colony open for another reason (and Liam is in a much milder climate than Finland), it surely can't do any harm, and it could be a bit of a help - especially if you target the nurse bees.


For treatment at this time of the year, is there anything better than sugar and hive sanitisers?
Or is the advice to just let things slide until Oxalic at Christmas?


Found this on here

{referencing a linked article - see below}
Further down the article has a section where it states using a european dust bellows to pump a sugar dust cloud into the hive can achieve an 80% to 85% mite drop.
That is exactly the kind of kit ive been looking for! Thanks for bringing that article to me

That post is followed by a link to a 2kg capacity sugar dusting bellows (about £30), and there is a 1kg capacity sugar dusting bellows in T's catalogue at about £20. Which is still overkill for my usage (50g of sugar each time?) and probably for Liam's as well.





The link referred to above seems to be broken, but I think that it was to this article http://scientificbeekeeping.com/pow...weet-and-safe-but-does-it-really-work-part-1/
And the article has an interesting (bang up-to-date) update

Update: Oct 25, 2011 Fakhimzadeh, Ellis and Hayes (2011) Physical control of varroa mites (Varroa destructor): the effects of various dust materials on varroa mite fall from adult honey bees (Apis mellifera) in vitro. Journal of Apicultural Research 50(3): 203-211.

The researchers found that the type of dust makes a big difference! Very fine dry sugar dust is the best–you would probably need to make it yourself (they used a coffee grinder). It also needs to be kept very dry–the humidity again appears to be a limiting factor in sugar dust efficacy.

They found that very fine pure sugar dust dropped more mites than confectioner’s powdered sugar containing corn starch (70-80% drop over 24 hrs, as opposed to 50%).

Note that they also found that Slovenian powdered sugar (which was the most effective at dropping varroa), was unfortunately quite toxic to adult bees! They presumed that the toxicity was due to the added anticaking agents dicalcium phosphate and silicon dioxide. This is surprising, since the first is a common animal food additive as a mineral source, and the second is made from finely ground quartz, and normally considered to be inert.

 

[Cazza]

.
It seems to be allways guys which want to put his own spoon in the soup and know better the issue than a 10 years lasted researching project.

.

Is that a Finnish proverb?
An office of speech and language therapists has just spent 5 minutes discussing this.
Cazza

 

[itma]

Is that a Finnish proverb?

Just a description of Nokia!

 

[Finman]

Is that a Finnish proverb?
An office of speech and language therapists has just spent 5 minutes discussing this.
Cazza

I do not know where the proverb has born but it is here in common usage.

An example from google : " Russia pushes its spoon into the Finnish shildren protection soup".

It means that the issue is allready meshy and then some outsider comes and starts to stir it.