# OA dribble frequency



## DrJeseuss (May 28, 2015)

If I treat nucs now with oxalic acid dribble, will they be ok to receive OA dribble or OAV as a fall treatment or should they be skipped until next year?

Also, since oxalic seems to shorten the bees lifespan does OA dribble or vapor have noticeable effect on the queens lifespan?


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## snl (Nov 20, 2009)

OAV does not, but dribbling does. The reason dribbling shortens their life span is that the bees digest the OA. Dribbling should only be done once, where OAV can be applied multiple times.


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## DrJeseuss (May 28, 2015)

How often is once? Year? Lifespan of workers (60-90 days)? I've read the dribble is harsh to winter bees since they 'hold it in' longer while summer bees see less impact as they cleanse more often. And what of the queen? Does she lose 20% lifespan per application over her lifetime? I am intending to use OAV primarily but feel there could be times dribble will fit the situation better.


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## snl (Nov 20, 2009)

DrJeseuss said:


> How often is once? Year? Lifespan of workers (60-90 days)? I've read the dribble is harsh to winter bees since they 'hold it in' longer while summer bees see less impact as they cleanse more often. And what of the queen? Does she lose 20% lifespan per application over her lifetime? I am intending to use OAV primarily but feel there could be times dribble will fit the situation better.


Lifespan of workers (which is far longer in winter). On dribble for the queen, I do not know, but since the workers feed her, I would guess that it does affect her, but how much? good question.


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## DrJeseuss (May 28, 2015)

Yesterday was treatment day. I tried two tactics. I treated 2 nucs with OA dribble, and one with OAV. Here are my beginner findings of the two:

Oxalic Acid Dribble: Mixing this was a chore. The portions at hand meant I ended up with a much larger amount than I will need and will likely expire before I use it all. I produced roughly 1 Liter. Getting the OA measured properly was just a matter of math, though I admit I did the calculations about 5 times, compared to various other sources, considered if I wanted to use W:W or W:v, etc. Now having done it, I could replicate this process easily, but that was not for the faint of heart. Also, I feel I used FAR more OA this way to treat the same size colony, not as good a value despite the overall low cost of either method. I applied 5ml per seam using a syringe. This part was very easy and felt quite safe. At first it didn't seems to be any disturbance to the bees other than to be givving them some sweet raindrops. Within minutes I noticed bees conllectng at the enterance as has been noted in other sources. Within about an hour, I pulled the cover to have a peek. I didn't notice any dead bees, but did see that the entire population had moved from the various frame seams and nearly all were packed into the space between the last frame and outer wall. The following morning, their activity appeared normal externally, though I did not open the hive. Also, these nucs have solid bottom so I'm unable to get a mite count from them. The treatment appears to disturb the bees, even if only in short term, and 'wastes' a larger amount of OA than I'd like overall. I'm uncertain yet of effect on mites, I'll follow these colonies through the summer.

Oxalic Acid Vapor: I build a contraption to apply this treatment. Essentially, I attached a copper pipe, closed on one end, through a board. The board also has a window of clear plexi so I could see the vapor and know when started and done. The board had gasket on the back side to seal firmly to the back of my SBB. I inserted a solid board in the SBB. Next, I closed the front enterance, and removed the vented inner cover, allowing the telescoping cover to sit firmly across the top for a seal. I added 1 gram of OA to the pipe, inserted into the board, and began applying heat to the pipe with a torch of a low setting. I moved the torch across the length of the pipe, then paused, slowly working the temp up. Within about a minute or so, I saw puffs of while vapor billowing from the pipe. I increased my pauses between heating to avoid burning the OA, and continued until the vapors stopped. This happened fairly quickly, maybe a minute or so. I noticed through the window that a LOT of crystals formed immediately outside the pipe on the solid bottop, and on the slats directly above the pipe. This covered an area avout 3-4" across. I lef all in place, for the pipe to cool and vapor to clear. After about 10 minutes, I opened the top cover. The bees seemed totally unaffected. I could see crystals falling through the SBB from the frames. I removed the crystals from the solid board and returned it to get a count later. There were no mites at this time. Inside the hive, I could not see any crystals formed anywhere outside the area described before. The following morning, the solid board had crystals all over, but especially where the cluster was. Also, I located 19 dead mites (after roughly 12 hours post-treatment). I again cleared this fur further monitoring. The bees still seemed unaffected. This process used much less OA to treat the hive at a small scale. I certainly did not feel as safe applying this treatment. My contraption sealed the vapors in very well, and likely no respirator would be needed, but I'm not sure I'd feel comfortable about that. Also, when clearing the crystals from the solid board the following day, a light breeze gave me a smell of this process and gave me quite a caugh. In normal use, I think I'll prefer to remove the board and allow the crystals to fall below to the ground.

Overall, despite the safety risks involved, I certainly prefer the OAV. I'm going to continue to work on a better application method. I like to build things, so I'm sure by time I'm done tinkering, there will be glow plugs, temp sensors, some relays, a few ICs.... overcomplicated no doubt. Still, the torch/pipe worked quite well in a rush, but care must be taken not to cross the line into formic acid. Maybe the dribble will have worked as well, but the long-term impact concerns me. I'd rather take precaution against a risk than to negatively impact colony health long-term.

I'll post a pic of my applicator when I get a chance.


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## jwcarlson (Feb 14, 2014)

DrJeseuss said:


> Yesterday was treatment day. I tried two tactics. I treated 2 nucs with OA dribble, and one with OAV. Here are my beginner findings of the two:
> 
> Oxalic Acid Dribble: Mixing this was a chore. The portions at hand meant I ended up with a much larger amount than I will need and will likely expire before I use it all. I produced roughly 1 Liter. Getting the OA measured properly was just a matter of math, though I admit I did the calculations about 5 times, compared to various other sources, considered if I wanted to use W:W or W:v, etc. Now having done it, I could replicate this process easily, but that was not for the faint of heart. Also, I feel I used FAR more OA this way to treat the same size colony, not as good a value despite the overall low cost of either method. I applied 5ml per seam using a syringe. This part was very easy and felt quite safe. At first it didn't seems to be any disturbance to the bees other than to be givving them some sweet raindrops. Within minutes I noticed bees conllectng at the enterance as has been noted in other sources. Within about an hour, I pulled the cover to have a peek. I didn't notice any dead bees, but did see that the entire population had moved from the various frame seams and nearly all were packed into the space between the last frame and outer wall. The following morning, their activity appeared normal externally, though I did not open the hive. Also, these nucs have solid bottom so I'm unable to get a mite count from them. The treatment appears to disturb the bees, even if only in short term, and 'wastes' a larger amount of OA than I'd like overall. I'm uncertain yet of effect on mites, I'll follow these colonies through the summer.
> 
> ...


Got any pictures? Also, does anyone know if you can OAV from the top of the hive as effectively? It would seem to me that it would be perhaps less effective. But if I build a plexiglass topped "top", I could more easily monitor the vapor progress. 

I suspect that crystals form immediately outside the pipe if you're not heating it *quite* enough. I noticed this this past winter once or twice when I was really trying to feather the temperature using one of those infrared temp guns or when a bee decided to crawl into the pipe. I finally just kind of gave up monitoring temp and just take it easy when I'm heating. I'm going to start doing this fairly frequently here in a bit because I have splits that will be broodless here in the next few days and once the queens are laying well I'm going to OAV them once or twice before brood gets capped again. If I could use a nice handy plexiglass top that would really make my life a lot easier than messing with the entrance to put my "custom" entrance reducer with 1/2" hole for copper pipe like I am now.

Or I could just buy a vaporizer from SNL, just hard to bite that bullet.

I noticed that the hive suddenly starts humming very loudly once the "cloud" hits them. I'm assuming they're fanning it around.


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## snl (Nov 20, 2009)

jwcarlson said:


> Also, does anyone know if you can OAV from the top of the hive as effectively? It would seem to me that it would be perhaps less effective.


You can vaporize from the top down and yes it is just as effective. BTW, buy the Vaporizer once and future treatments are less than $.10 each.


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## jwcarlson (Feb 14, 2014)

snl said:


> You can vaporize from the top down and yes it is just as effective. BTW, buy the Vaporizer once and future treatments are less than $.10 each.


I know. My $5 copper pipe worked in a pinch last winter so I've just kept using it. It's a bit clunky though, I will admit. Buying it at this point is more likely a matter of when. Not worried about the cost of the OA crystals, seems like I got a lifetime supply already. When considering buying the vaporizer or more boxes the boxes have won out so far.


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## rookie2531 (Jul 28, 2014)

DrJess, when you saw the crystals forming on the outer part of the pipe, that indicates, a bad burn. You probably, only got a small fraction of the vapors you should have. I too built a top cover/crack pipe method burner with a plexiglass top and never could be consistent enough, even while I was able to see the vapors working, then in a flash, crystals shoot out on the outer edge of the pipe. That is a failed attempt.


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## DrJeseuss (May 28, 2015)

rookie2531 said:


> DrJess, when you saw the crystals forming on the outer part of the pipe, that indicates, a bad burn.


I'm guessing the pipe was hot enough to vaporize the crystals, but the air in and near the pipe was too cool, causing near instand crystalization. Does that sound right? To remedy this, I'm thinking the temp should come up near, but not past the low end (315*F) to heat both pipe and air, then ramp up well into the range, but not high enough still to burn. I'm betting mine got to temp too fast causing the issue. As I did get a good bit of mite drop considering the low population of this nuc, and since I used 1 gram on a single medium super with only five frames (I believe the 'dose' covers the airspace of the hive regardless of frame count, right?), I'm hoping it at least served as a good trial run and will await fall/winter to redo this treatment. I will likely give a run on a different hive. It has brood so it will not be fully effective, but that hive has signs of DWV so I'd like to knock back the population before that spreads with the drones. I have drone frame in that hive currently in hopes of breaking the mite cycle as well.


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## asd (Jun 10, 2015)

Treat the nucs using the dribble method on day 21 after making them(on this day they have no capped brood left). Randy Oliver does this and it makes a lot of sense. However I would make a few mite samples first to see if it is the case for a treatment.


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## DrJeseuss (May 28, 2015)

When treating my 3 nucs, I ensured there was no capped brood to ensure all mites were phoretic. I know the donor colony had mites (of normal levels) when I made these up. In any case, even if only 1 mite, I felt I wanted these small nucs to have as near zero mites as possible to give them a healthy start.

As a followup to my notes above about the treatment experience... The disturbed colonies that received OA Dribble appear to have returned to normal life. I will open them this weekend to check for mite fall and/or dead bees. These nucs have solid, attached bottoms so I must remove frames to see this. As for the OAV nuc, I saw 22 mites yesterday on the board, and only 1 today (42 total). This nuc has a low population (started as 2-frame and lost some to drift since makeup), so I feel this is a good kill based on what I expected them to have. I'm comfortable they are now light to none, and will not treat any of these nucs until a fall treatment of OAV only IF I see a high count from samples, otherwise, I'll catch them early in spring before brood buildup.

Also, here is a pic of the 'device' I made to treat with OAV. This was held to the SBB with 2 36" clamps front to back. Weather strip on the opposite side sealed this board to the SBB all around. The pipe and window are both in the gap between the screen and the counting board. The pipe enters at about a 45* angle to the board so the vapor would eject in front of the window toward the center of the hive body. A flashlight airmed into the window lit the vapor very well so it could be easily seen without getting my face near the window... I was able to work at arms length throughout the process. From reading other's comments on this method, I think my flaw is the overall length of the pipe used. It's a plumbing stub-out, so it's capped at one end, and had a 90* bend in it. I pulled this out to about 45*, but the length is unchanged. I suspect my issue was that despite trying to evenly heat the full length of pipe, the top end was cool compared to the tip where the powder was, so it began cooling as it climbed the pipe. I was hesitant to torch too close to the window as it's made from a clipped out piece of clear plastic packaging, and would quickly melt through. I was able to heat to the bend, but not between bend and hive.









Thanks all for the help and suggestions!


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## jwcarlson (Feb 14, 2014)

DrJeseuss said:


> When treating my 3 nucs, I ensured there was no capped brood to ensure all mites were phoretic. I know the donor colony had mites (of normal levels) when I made these up. In any case, even if only 1 mite, I felt I wanted these small nucs to have as near zero mites as possible to give them a healthy start.
> 
> As a followup to my notes above about the treatment experience... The disturbed colonies that received OA Dribble appear to have returned to normal life. I will open them this weekend to check for mite fall and/or dead bees. These nucs have solid, attached bottoms so I must remove frames to see this. As for the OAV nuc, I saw 22 mites yesterday on the board, and only 1 today (42 total). This nuc has a low population (started as 2-frame and lost some to drift since makeup), so I feel this is a good kill based on what I expected them to have. I'm comfortable they are now light to none, and will not treat any of these nucs until a fall treatment of OAV only IF I see a high count from samples, otherwise, I'll catch them early in spring before brood buildup.
> 
> ...


I agree that your pipe is probably too long. Too much space for it to cool down before getting to the hive. I noticed crystals in mine when it was really windy and about 40*F. Figured fighting the wind was cooling the pipe too much.


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## DrJeseuss (May 28, 2015)

I was able to check the hives yesterday. In those that got the dribble, the bees had a pile of 'trash' in one corner, where all the mites were found dead. I wasn't able to get a count, but would guess it nearly the same as the oav hive. Activity normal and mite drop nearly the same... I'd say these treatments will come down to preference as to ease. Im leaning to oav simply due to possible concerns about long term damage.


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