Beemaster's International Beekeeping Forum

Found this as a different varroa treatment. http://www.beespace.me/rhubarb-bees-and-varroa , Could belong in the treatment free section or here.  It's a interesting idea and looks like it would work in principal.

Good article. Thanks for posting.
Jim

I was reading a separate article yesterday regarding oxalic acid.  The method in it was comparing applying OA to top bars of the frames at a rate of 3% per hive vs dribble between frames, also at 3% per hive. 
Does anyone here know what the hell - 3% per hive - means?   It was otherwise a very well structured and well written scientific report.  The 3%ph though, is meaningless and completely discredited it to me and I promptly quit reading.  If they cannot get the units right then the whole thing is trash.  Unless perhaps I am the one needing educating. 

Quote from: TheHoneyPump on October 22, 2018, 01:20:39 PM
I was reading a separate article yesterday regarding oxalic acid.  The method in it was comparing applying OA to top bars of the frames at a rate of 3% per hive vs dribble between frames, also at 3% per hive. 
Does anyone here know what the hell - 3% per hive - means?   It was otherwise a very well structured and well written scientific report.  The 3%ph though, is meaningless and completely discredited it to me and I promptly quit reading.  If they cannot get the units right then the whole thing is trash.  Unless perhaps I am the one needing educating. 

A guess, a pretty good one in my opinion:
in Germany, for dribbling, we use a 3,5% oxalic acid / water mixture (usually with sugar in it, but 3,5% OA). For spraying, we use (now may, as it is just being legal) 3,0% watery solution. in Italy e.g. the percentage for dribbling is higher. Probabyl cause they dribble in summer when it doesn`t work so well.
I have read of a commercial outfit where they dribbled on the top-bars repeatedly (in breeding hives). They seemed to be content with the results. The liquid contained sugar.

I once did a block-treatment on some hives with dribbling appr. 50 ml of 3,5% OA in late summer about 3 times with 6 d intervals.. They wintered in less populous than the ones treated with formic acid at the same times. With OAV I would assume a better surving-rate of bees. But I am not finished with experimenting on that. In summer, I still use formic acid as it is faster than my gizmo.

This has been going around for many, many years.  Some of the early references I could quickly find were from 2006.  I was looking for some specifics, but can't find that reference.  The density is .3 to 1.5% OA with about 95% being water and the rest being all sorts of chemicals.  I suppose that wouldn't be too much volume to put in a hive, but how does it "off gas" and spread?  In any case, I haven't found any real studies that prove it works.  I suspect that if it were a reasonable possibility, some of the heavy-weights in varroa testing and treatment would have tried it or even written about it.

Here is a link of the chemical  breakdown of the plant.  There are too many variables and unknown impacts for me to try it; especially with the cost of OA in a container.
http://nopr.niscair.res.in/bitstream/123456789/26456/1/JSIR%2060(1)%201-9.pdf (http://nopr.niscair.res.in/bitstream/123456789/26456/1/JSIR%2060(1)%201-9.pdf)

Quote from: blackforest beekeeper on October 22, 2018, 02:43:06 PM

Quote from: TheHoneyPump on October 22, 2018, 01:20:39 PM
I was reading a separate article yesterday regarding oxalic acid.  The method in it was comparing applying OA to top bars of the frames at a rate of 3% per hive vs dribble between frames, also at 3% per hive. 
Does anyone here know what the hell - 3% per hive - means?   It was otherwise a very well structured and well written scientific report.  The 3%ph though, is meaningless and completely discredited it to me and I promptly quit reading.  If they cannot get the units right then the whole thing is trash.  Unless perhaps I am the one needing educating. 

A guess, a pretty good one in my opinion:
in Germany, for dribbling, we use a 3,5% oxalic acid / water mixture (usually with sugar in it, but 3,5% OA). For spraying, we use (now may, as it is just being legal) 3,0% watery solution. in Italy e.g. the percentage for dribbling is higher. Probabyl cause they dribble in summer when it doesn`t work so well.
I have read of a commercial outfit where they dribbled on the top-bars repeatedly (in breeding hives). They seemed to be content with the results. The liquid contained sugar.

I once did a block-treatment on some hives with dribbling appr. 50 ml of 3,5% OA in late summer about 3 times with 6 d intervals.. They wintered in less populous than the ones treated with formic acid at the same times. With OAV I would assume a better surving-rate of bees. But I am not finished with experimenting on that. In summer, I still use formic acid as it is faster than my gizmo.

Ah ok.  So the clarification then is - an aqueous solution with some sugar and 3% oxalic acid concentration in the solution.   That is not  -3% per hive-.  That is 3% oxalic acid solution.   Got it now, thanks.

... sorry for the distraction, the hijack.    Now back to talking about chewing leaves .....