Mixing oxalic & syrup

[OXFORDBEE]

It is also an additional stress, and even the fact that they were using caged bees makes them more vulnerable to stresses of various kinds.

G.

What about.... Oxalic acid: A prospective tool for reducing Varroa mite populations in package bees.

 

[OXFORDBEE]

Now why would each new research seem be making the percentage of oxalic acid less.

Sublethal effects of oxalic acid on Apis mellifera
(Hymenoptera: Apidae): changes in behaviour
and longevity

Saskia SCHNEIDER, Dorothea EISENHARDT, Eva RADEMACHER

Treatment with a 3.5% solution of oxalic acid dehydrate (OA), corresponding to the dosage of 175 μg/bee, causes sublethal effects on A. mellifera. The decreased activity and nursing as well as the reduced lifespan of treated bees are aspects for a permanent damage due to the treatment with OA.

 

[Finman]

.
'However, wintered bees will all die before the hive gather new yield.
It is same what oxalic acid makes to them.

The reduction of bees is not essential. Numerous researches have shown
that trickling does not affect on spring build up.

Neither is affects on the queen. Trickled hives have often 3-4 years old queens.



I have seen many times what varroa does to big hives.
In August the hive may have 7 box bees and after 2 months it is empty.


I do not cry for handfull of bees

.

 

[OXFORDBEE]

.

I have seen many times what varroa does to big hives.
In August the hive may have 7 box bees and after 2 months it is empty.

I have not seen this with my hives. Am I doing something wrong??

 

[Finman]

I have not seen this with my hives. Am I doing something wrong??

I have seen mites in my hives 28 years. I have seen many things.

Continue your way. It is good.
Stop treating if you want to see.

I hope that helps.

(I hate sometimes English humour)

 

[Hivemaker.]

0B

This one may also be of use for package bees.. 0.5% caused no harm, while 1.0 % and 1.5% were highly toxic.


http://www.eau.ee/~agronomy/vol08Spec2/p08s207.pdf

 

[gavin]

Not quite 'no harm', just no significant level of harm.

I wonder why they did not use any sugar in their spray treatment?

G.

 

[Hivemaker.]

I don't really know Gavin,perhaps because in another research they found it to be more harmful with sugar, as the bees ingested more of it.

I think try this, or the other option may be sublimation of of oxalic for the packages.

 

[gavin]

Yet the paper Oxfordbee quoted above claims little effect of 3ml of 2.8% (aka 3.5%!) oxalic on packages. There does look to be a small effect, but it isn't significant. Implies that with sugar the bees suffer less.

 

[Hivemaker.]

Strange is it not,all these researches seem to say different things.

 

[Hombre]

And from the couple that I have looked at, not advocated thymol or any other bactericide as being a sensible aid against nosema spores in the hive, as opposed to in the bees.

Also advocating the routine use of Oxytetracyclin.

So why should I really think them to know everything I ask myself . . .

I comply with the manufacturer's labeled instructions.

 

[Ruary]

The report clearly shows it is NOT "just as efficient at killing mites"!!

The tests results ( Table 1) show that there was no significant difference in using 37g oxalicacid dihydrate or 47g oxalic acid dihydrate and that equally there were no significant difference between 30g and 47g of oxaliacid dihydrate.

 

[MandF]

No "significant" difference in your opinion!

If, like me, you believe the whole point of using oxalic is to kill as many mites as possible, with no obvious/recorded detrimental effect on the colony (in terms of colony voracity/health) the next summer, then you will think the difference is significant.

I would rather have, or give my colonies the best chance of having, a smaller but fitter colony. Assuming the effects on bee numbers are the same here in western europe as with the trial results for central europe, which is a big assumption.

Did your report check for disease levels the following summer (dwv for example)?

And also, as I said previously, the varroa problem was a lot different 10+ years ago, and this might explain their ultimate recommendation... who cared if you had a "few more" varroa in the spring when you could use your pyrehtroid treatments with impunity. There is likely to be more than a "few more" too, as varroa breed exponentially.

Times have changed, and I personally think more people would choose to kill off more mites, especially as, anecdotally at least, everyone says there is no noticable effect on spring build up or colony performance.

 

[Finman]

The tests results ( Table 1) show that there was no significant difference in using 37g oxalicacid dihydrate or 47g oxalic acid dihydrate and that equally there were no significant difference between 30g and 47g of oxaliacid dihydrate.

There are only one oxalic acid to normal beekeeper and it is oxalic acid crystals. (I do not understand this hair splitting.

There are enough tolerance to make mistakes.

But what ever you do, trickling does not allways succeed, perhaps small amount of brood and something. Guys must do often spring treatments. - Like I have done last two years. Last spring spring treatment was succesfull but not 2 spring ago.

 

[Finman]

No "significant" difference in your opinion!

If, like me, you believe the whole point of using oxalic is to kill as many mites as possible,

Times have changed, and I personally think more people would choose to kill off more mites, especially as, anecdotally at least, everyone says there is no noticable effect on spring build up or colony performance.

That is correct way to think it. UK has so long brood period that hives meet troubles before autumn, if you do not get mite amount under 10 pieces per hive, you need early treatment in August.
.

month.... mites........ 10 or 50 in the start of February

2 …..... 10 …..... 50
3 …..... 20 …..... 100
4 …..... 40 …..... 200
5 …..... 80 …..... 400
6 …..... 160 …..... 800
7 …..... 320 …..... 1600
8 …..... 640 …..... 3200
9 …..... 1280 …..... 6400 end of September

As you see, with 50 mites start the critical limit goes over in July.

.

 

[Ruary]

No "significant" difference in your opinion!

.

Oh no not my opinion, it is in the Report.

The table 'Average effectiveness of the trickle treatment with oxalic acid (g oxalic acid dihydrate per 1 litre of sugar water (1:1 or 1:2 by weight) 1999/2000' Includes the results of significance tests (p<0.05) Using a multiple t test ( Tukey) after and angular transformation (Snedcor & Cochran 1980).

Please read the paper before casting aspersions.

 

[Ruary]

Did your report check for disease levels the following summer (dwv for example)?

Read the paper and your questions might be answered. the hives in all apiaries were checked for development in spring and in one apiary the number of checks needed to do this was three.

 

[Bead]

Susbees and myself have been discussing the details of what you need to do to convert the 6% to 4.5% if anyone is ready for that. It is a complex problem to solve completely accurately but we reckon that we're there within a few ml.

Yes please. I have bought the 6% premix and would like to dilute it.

 

[gavin]

Yes please. I have bought the 6% premix and would like to dilute it.

OK then, here goes ... the combined efforts of Susbees, her partner and myself .... a carefully considered way to convert the 6% solution to 4.5% (aka 3.2%) with the right strength of syrup too.

The Background

The 6% (weight/volume, dihydrate) oxalic solution in 30% syrup in one litre will have:

60g oxalic acid dihydrate + 300g sugar + 766ml added water (within a few ml we reckon)

It is hard to calculate this precisely as there are no known density tables for oxalic in syrup for example, so we have made a few assumptions.

That 60g, if diluted to the common recipe proportions of 75 + 1000 + 1000 (which gives the 4.5% OA dihydrate solution, also called 3.2% by those who make their calculations for anhydrous OA) requires this mix (proportionately reduced from the 75g mix):

60g OA dihydrate + 800g sugar + 800ml water

But you already have ....

60g + 300g sugar + 766ml water

The Recommendation

So, you need to tip your 1l into a larger container and add:

0 (none, zilch) oxalic acid + 500g sugar + 34 ml water, which will give you a volume of about 1336ml

That should give you enough for 267 seams of bees, maybe 38 colonies. If you are starting with a smaller quantity of 6%, get the calculator out.

Don't obsess about the weights and volumes, roughly will do. Then 5ml dribbled over each seam of bees up to a max of 50ml per colony (a couple of mine yesterday actually did have 10 seams of bees). I start with the solution at room temperature and don't worry if it cools as I do it. The volume is small and the bees are chilling anyway once the crownboard is off.

The Disclaimer and Safety Considerations

Those are our best efforts. Pretty sure the calculations are close, but on your own bees' heads be it.

Take care to avoid splashes, particularly in the eyes. Label appropriately and keep well out of the reach of children. Wash off any splashes with water. It isn't horribly corrosive but treat with care. Don't know what it does to clothes. I wear Marigolds while handling.

Don't keep for a second season. I discard small amounts of left-overs on bare soil but then we have plenty of that here. Don't use if the solution is yellowing.

Next year, buy from a supplier who supplies at 4.5% (w/v dihydrate) or 3.2% (w/v anhydrous), or make it up yourself from crystals (which keep indefinitely). Some prefer a more dilute solution. At least one of the 6% suppliers has said that they use it as is and are happy with it. Doesn't accord with the scientific literature, but if you use it unaltered it will probably work and the bees will probably (mostly) survive.

OK with that Susbees?

G.

 

[Bead]

Thanks Gavin (and Susbees).