2011 varroa levels

[Neils]

Absolutely not suggesting that Icing sugar is suitable as a main treatment nor that is terribly effective in isolation and I think if you start using it you pretty much have to keep using it every inspection throughout the season AND THEN TREAT with something effective.

I'm tyring to find the link for it, but I read a report suggesting that the lower the mite count the more reproductive varroa become.

But I do still believe that Icing sugar has a place if nothing else because I watch our ex inspector use it gauge mite levels on bee samples. Stick bees in jam jar, cover in icing sugar, shake them around a bit and see what drops off.

But let's be absolutely clear here I am not suggesting that icing sugar, in isolation, is a suitable control for varroa any more than having an open mesh floor is varroa control but it has its place as part of an IPM scheme. Whether you judge it to be worthwhile is a different question.

[gavin]

Never mind, you gave us an excuse to have a wee rant there. Members of my local association will recognise that need to vent about inappropriate reliance on ineffective methods.

Using icing/powdered sugar to assess the population of mites is fine by me. It was one of the recommended methods on the Varroa mapping page.

[The Drone Ranger]

I think generally it's a good idea to give different treatments a try.
I don't hold out much hope for sugar dusting (and it's a bit messy) it's gentle on the bees though
I also haven't much faith in spaying on lactic acid -
One year I was collecting varroa from the floors in winter and examining them under a microscope to see if they still had oxalic acid crystals on their bodies ( I was trying to work out the best timing for second oxalic evaporation treatment)

Anyway after counting the drop the floor sweepings were stored for 8 days before I got round to checking some of them for crystals and I still found varroa which were alive after getting the first oxalic treatment and lying on an insert in sub zero temps for 5 days. (cold probably helped survival)

So I took a couple of survivors and put a couple of drops of lactic acid (as sold by Thornes) on the slide -- 2 Hours later they were still wiggling their toes at me and not being a torturer by nature I gave up and squashed them.

What frustrates me, is after I have knocked myself out year after year trying to kill off varroa, someone pops up claiming the moral high ground saying they are breeding for resistance (usually followed by the question have I any bees for sale ?? -- two word reply ---unprintable)

The argument that the natural resistance will appear is illogical
If that really worked then people in areas where malaria is prevalent would sensibly be protected by a very thick skin
In fact natural selection at a cellular/immune system level, results instead in Sickle Cell Anemia--itself a killer.
Varroa have a much more adaptable breeding model as far as natural selection goes (many mothers, inbreeding, mutation etc)
You are more likely to breed a more benign varroa than a resistant bee.

[gavin]

You are more likely to breed a more benign varroa than a resistant bee.

If there was a mechanism to support the individual mild mite in a population of aggressive, multiplying ones. The idea that whole colonies of bees with non-aggressive mites is the ideal doesn't account for the mite-to-mite competition that must take place all the time.

G.

PS Mite tolerant bees exist, no question. Maybe they are not good enough, but they are there.

[The Drone Ranger]

If there was a mechanism to support the individual mild mite in a population of aggressive, multiplying ones. The idea that whole colonies of bees with non-aggressive mites is the ideal doesn't account for the mite-to-mite competition that must take place all the time.

The theory is aggressive virile mites kill the colony and less productive slower reproducing weaker mites don't

As you say Gavin
"Mite tolerant bees exist, no question. Maybe they are not good enough, but they are there."

That's the hygenic gene theory of mite control.
That's fine in principle and 75 years ago the same mechanism was supposed to be going to eradicate foulbrood (as I wrote in SBA mag last month)

If I walked out to my garden now I could photograph a rabbit in the middle of the lawn , its eyes are puffed and closed its breathing wheezy. It is suffering from the effects of myxomatosis.
Most likely a flea bite introduced the virus and what we see is death by secondary infection , pneumonia etc.
The rabbit may survive 10% certainly do because they have some resistance but they are weakened damaged often sterile and have a much reduced lifespan.

In the SBA mag Eric MacArthur and others often quote this so called resistance to myxamatosis as an example of how bees will develop resistance to varroa.
Well that rabbit has fleas it hasn't learned to get rid of them and it most likely never will. It's obvious to us the problem is the fleas but to the rabbit's defence mechanisms the problem is virus.

Bees which have some resistance to varroa may well be useless in every other way and it doesn't confer on them the ability to resist virus and other disease in fact they could be weakened and more vunerable.

[Jon]

The theory is aggressive virile mites kill the colony and less productive slower reproducing weaker mites don't

That's the theory, but it doesn't really stack up. if you have fast reproducing and slow reproducing mites in a colony the fast reproducing ones will soon dominate.
If the colony starts to collapse due to mite load it will be robbed out by neighbours and the mites will hitch a lift elsewhere.
Slow reproducing mites could coexist with bee colonies if there were no faster reproducing mites present but I cannot see how a situation could arise where faster reproducing mites disappear.

[The Drone Ranger]

That's the theory, but it doesn't really stack up. if you have fast reproducing and slow reproducing mites in a colony the fast reproducing ones will soon dominate.
If the colony starts to collapse due to mite load it will be robbed out by neighbours and the mites will hitch a lift elsewhere.
Slow reproducing mites could coexist with bee colonies if there were no faster reproducing mites present but I cannot see how a situation could arise where faster reproducing mites disappear.

Totally agree with you on that Jon in fact any of the theories of how the bees can defeat the mites without help seem weak to me.
I personally think everyone should try to remove as many mites as they possibly can.
We don't wait for the cat to develop a strategy for dealing with fleas we treat the cat's fleas by sterilising them for the benefit of the cat (and ourselves)

[Jon]

Totally agree with you on that Jon in fact any of the theories of how the bees can defeat the mites without help seem weak to me.
I personally think everyone should try to remove as many mites as they possibly can.

I agree, but it is worth keeping a close eye on colonies which seem better able to coexist with mites for whatever reason. VSH, more effective grooming or something else. I don't see any magic bullet though. The Russian (Primorski) strain has coexisted with varroa for about 150 years and has developed some resistance.
The 'right on' no treatment people are just killing bee colonies with no possible benefit as resistance is highly unlikely to arise in this way.
On the Irish list Dan Basterfield memorably likened the no treatment strategy as being akin to dropping babies off a bridge with regard to what it tells you about ability to cope.
My Apiguard treatment is just about finished and I will do an oxalic acid treatment after the first decent cold snap in December.
I cannot believe the low mite fall I am seeing this year, just a few dozen it seems although half my colonies are on solid floors so I don't have an insert tray to monitor.

[The Drone Ranger]

Lots of people seduced by the "lets breed for resistance" bandwagon have learned the hard way and abandoned that strategy which is better for everyone.

It doesn't take that many people to drop out of the measles vaccine program to get a serious outbreak.

[Jon]

I think any breeding for resistance should be a gradual thing rather than some kind of cold turkey treatment.
I don't think it is futile at all but I think it needs to be carefully thought through.
The non-treaters imagine that 50% of their colonies will survive and breeding from survivors will lead to more mite resistant bees.
Nice theory but not grounded in reality.
The thing is, survival is more likely to be 5.0%.or 0.5% than 50% and you would need to be starting with a very large number of colonies and be prepared to lose most of them in the short to mid term.
You only have to read biobees.com to get an idea of how many people are losing their bees over and over again, including most of the gurus.
Groundhog beekeeping.
I don't know how they keep the faith in the face of such catastrophic losses.
It must be the ranting against Bayer and the neonicotinoids which keeps them going as it sure ain't the beekeeping success.