# high mite drop after OAV



## hex0rz

Having that mite drop means it's working...


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## Specialkayme

OAV is not recommended when brood is present. You can use it, but other options are usually the better route.


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## shinbone

This is just me, but if you continue with the OAV, I'd think about applying it every 3rd day.


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## baybee

shinbone said:


> This is just me, but if you continue with the OAV, I'd think about applying it every 3rd day.


Thanks. If applied every 3rd day, should 5-6 applications be enough? Or how many should be enough to know that it's not going to work and that MAQs would be less stressful?


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## hex0rz

Uhm, have you researched a mites life cycle?


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## Marti

Last 2 years I have had a couple(differnet hives each year) of hives with 1000 plus mite drop 24 hour after vaporization. It took 8 treatments 5-7 days apart to get the 24 hour mite drop down to >100 in 24 hours. Then, one more teatment between Thanksgiving and Christmas. 
MAQS would have been much easier, but I don't want to take the chance of losing a queen late in the season.


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## Kuro

Specialkayme said:


> OAV is not recommended when brood is present. You can use it, but other options are usually the better route.


Last summer-fall I attempted to control varroa in my 3 hives by OAV (I tried every 4 days, every 3 days and finally every other day). 50-500 mites kept falling 48 hr after each OAV no matter how I did It. I ended up doing 27 vaporizations until early December when mites finally stopped falling (by then the bees probably stopped brooding). One hive died in late January, and another was found queen-less at the first inspection in mid March. This summer I used MAQS (will also do a round of OAV beginning late November). Lessons learned.


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## baybee

Appreciate all the responses!



Marti said:


> Last 2 years I have had a couple(differnet hives each year) of hives with 1000 plus mite drop 24 hour after vaporization. It took 8 treatments 5-7 days apart to get the 24 hour mite drop down to >100 in 24 hours. Then, one more teatment between Thanksgiving and Christmas.
> MAQS would have been much easier, but I don't want to take the chance of losing a queen late in the season.


Do you mean the hives did okay with 100 mites/24 hr post-treatment for a couple of months? 

Yes, they say MAQS are harder on the bees, but if the temps aren't too high the damage seems to be tolerable. I don't know the actual mite load, but can MAQS still be used on hives with a high load?


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## baybee

Kuro said:


> Last summer-fall I attempted to control varroa in my 3 hives by OAV (I tried every 4 days, every 3 days and finally every other day). 50-500 mites kept falling 48 hr after each OAV no matter how I did It. I ended up doing 27 vaporizations until early December when mites finally stopped falling (by then the bees probably stopped brooding). One hive died in late January, and another was found queen-less at the first inspection in mid March. This summer I used MAQS (will also do a round of OAV beginning late November). Lessons learned.


Has OA residue inside the hives accumulated to the level deadly for the bees? Or the hives suffered from PMS?


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## baybee

hex0rz said:


> Uhm, have you researched a mites life cycle?


Okay, seven treatments three days apart.


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## odfrank

baybee said:


> Okay, seven treatments three days apart.


I have over 150 hives spread over 30 sites. How long will seven treatments three days apart take me?


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## Charlie B

odfrank said:


> I have over 150 hives spread over 30 sites. How long will seven treatments three days apart take me?


If you really cared about your bees you wouldn't even ask that!


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## baybee

odfrank said:


> I have over 150 hives spread over 30 sites. How long will seven treatments three days apart take me?


It depends on how many vaporizers with batteries are available to use simultaneously. More importantly, is OAV even effective this time of year?

Odfrank, may I ask you what would be your preferred anti-Varroa treatment this time of year?


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## msl

Charlie B said:


> If you really cared about your bees you wouldn't even ask that!


he doesn't, he just knows he will trap more


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## hex0rz

Effective, yes. Even good enough for winter prep too. It's in timing. Your never going to totally eradicate the mites. You just have to keep them below threshold level.

Here's the kicker though, how many hives are around you that you know of or don't know of, kept or feral? As they collapse those bees risk bombing your hive with mites and then yours collapses. At this rate it can be an ongoing issue.

I think personally, the most sure treatment at this time of year is apivar.


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## aran

i used OAV last year with good success with 9/11 hives surviving winter in upstate NY.
Now though after splits and raising queens i have 23 hives so i decided OAV was too time consuming so i did MAQS in mid to late spring ( had surgery so got to this late) and i just put MAQS on the hives again yesterday.

I lost no queens with the first round of MAQS so hopefully the same happens this second time around. I read the article on scientific beekeeping and noted the 1 strip vs 2 strip results. I used 2 strips the first time around but only used 1 strip yesterday just out of fears of losing queens this late in the season. I will use OAV when they are broodless in the coming months also.


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## Marti

Yes the hives did survive the winter and had to be spit in the spring. 

Can MAQS still be used on hives with a high load? Yes


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## aunt betty

Have not used MAQ's for two seasons. Got my boxes yesterday.
Is it me or are the MAQ sachets smaller now? 
Seem to remember them being much wider. 

Have done about 15 MAQ treatments but it was two summers ago. No queens lost.
Saved the remaining 10 treatments until the next spring. By then they were duds. Live n learn.


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## Kuro

baybee said:


> Has OA residue inside the hives accumulated to the level deadly for the bees? Or the hives suffered from PMS?


Throughout the fall, all three hives looked healthy (no K wings) and well populated despite high mite counts. However, they all began to show signs of dysentery in mid December and the population seemed to have decreased much by late January. In the dead hive (5-frame nuc), I found a surprisingly small number of workers (<500), some brood, and the queen. The sample was sent to Beltsville bee lab and tested negative for nosema and 0.3% varroa. 

My guess is that the persistent infestation of varroa throughout late summer - late fall shortened the life span of winter bees and the small colony in the nuc could not maintain warmth and died. The two full-sized hives (one was found queenless) survived but their populations were very small compared to those in the previous spring. I also wondered whether the dysentery was caused by OA-contaminated honey after too many vaporizations, but I have not found such a report.


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## baybee

aunt betty said:


> Have not used MAQ's for two seasons. Got my boxes yesterday.
> Is it me or are the MAQ sachets smaller now?
> Seem to remember them being much wider.
> 
> Have done about 15 MAQ treatments but it was two summers ago. No queens lost.
> Saved the remaining 10 treatments until the next spring. By then they were duds. Live n learn.


Yes, they also sell now "Formic Pro", which has longer shelf life and (maybe?) releases FA more slowly. People say freezing MAQs keeps them forever.


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## baybee

Kuro said:


> ... I also wondered whether the dysentery was caused by OA-contaminated honey after too many vaporizations, but I have not found such a report.


There has to be some sort of overdose on OA after too many vaporizations. Re-crystalizing acid might dissolve in condensation moisture on the walls, and honey.


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## baybee

Marti said:


> Yes the hives did survive the winter and had to be spit in the spring.
> 
> Can MAQS still be used on hives with a high load? Yes


Thanks. This probably means 100 or so mites 24 hr post treatment is below infestation treshold: 100 phoretic, 500 capped, 600 total at worst.


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## baybee

hex0rz said:


> ...
> 
> Here's the kicker though, how many hives are around you that you know of or don't know of, kept or feral? As they collapse those bees risk bombing your hive with mites and then yours collapses. At this rate it can be an ongoing issue.
> 
> I think personally, the most sure treatment at this time of year is apivar.


Thank you, will see if I can get a bit of Apivar.

I'm sure there are some bees around because the spring before I started the neighbor got a huge swarm on his apple tree. He thought they were feral as he couldn't remember anyone around keeping backyard bees.

I hope re-infestation with mite bombs goes slowly enough so I can detect it.


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## dudelt

Kuro said:


> I also wondered whether the dysentery was caused by OA-contaminated honey after too many vaporizations, but I have not found such a report.


Kuro, I would doubt it was caused by OA contaminated honey. I would assume that most of the honey in the hive was capped when you vaporized. Since the OA does not penetrate the cappings, only the uncapped honey could possibly get contaminated. When you treat a hive with OAD, the concentration of the OA is much higher in the sugar water than the contamination you would get from vaporizing. While there are some noted side effects from using OAD, dysentery is not one of them that I am aware of. Thus, I would doubt that OA contamination from vaporizing would be the cause. Clearly, your hives had mite pressure from outside your hives. My advice in a case like yours would be to use Apivar instead of MAQS. MAQS will do a really nice job of killing the mites in the hive for a few days of treatment but once the treatment ends, if mites are being brought into the hive from elsewhere, you still have a major problem. Apivar's long treatment time is useful in these cases. This is where a good monitoring plan comes in handy. You can treat with MAQS (or any other product) and believe everything is perfect when in fact, you can get reinfested fairly quickly.


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## Kuro

dudelt said:


> Kuro, I would doubt it was caused by OA contaminated honey. I would assume that most of the honey in the hive was capped when you vaporized. Since the OA does not penetrate the cappings, only the uncapped honey could possibly get contaminated. When you treat a hive with OAD, the concentration of the OA is much higher in the sugar water than the contamination you would get from vaporizing. While there are some noted side effects from using OAD, dysentery is not one of them that I am aware of. Thus, I would doubt that OA contamination from vaporizing would be the cause. Clearly, your hives had mite pressure from outside your hives. My advice in a case like yours would be to use Apivar instead of MAQS. MAQS will do a really nice job of killing the mites in the hive for a few days of treatment but once the treatment ends, if mites are being brought into the hive from elsewhere, you still have a major problem. Apivar's long treatment time is useful in these cases. This is where a good monitoring plan comes in handy. You can treat with MAQS (or any other product) and believe everything is perfect when in fact, you can get reinfested fairly quickly.


Good points, I still have some honey supers (I did MAQS on 8/11), which I plan to extract shortly before the ivy flow. If mite counts bounce back by then, I’ll definitely use Apivar after removing supers.


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## baybee

Update on mite drops during OAV every 5th day.

Over five days after the first vaporization 600 mites dropped.
After the second vaporization: 

1st day drop -- 350;
2nd day drop -- 350;
3rd day drop -- 120.

The 3rd day drop is only 1/3 of the first two. Does this mean that the hive has cleaned out all OA by now and ready for a new vaporization? Or the hive ran out of the phoretic mites?


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## baybee

Duplicate!


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## hex0rz

As far as mite bombings go, i think it causes a fairly good spike in mite numbers pretty quickly. I've never tracked my hives for such a thing but these are things i have been told about the subject.


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## dudelt

baybee said:


> Does this mean that the hive has cleaned out all OA by now and ready for a new vaporization? Or the hive ran out of the phoretic mites?


It simply means that the number of phoretic mites is much lower than before. Remember, OA after vaporization works for about 3 days. You do not want to immediately vaporize at the three day mark. The mites that hatch and come out from under the cappings will not immediately be ready to mate again. Wait until the 5th or 7th days after the previous vaporization date to do it again. According to this article: http://articles.extension.org/pages/65450/varroa-mite-reproductive-biology The phoretic stage lasts about 5-11 days when brood is present. Thus, if you vaporize and the OA is active for three days, if you vaporize on the 7th day, very few mites will have gone under the cappings that had just hatched. Some will have but you CANNOT kill every mite with any known treatment, even though you want to.


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## baybee

hex0rz said:


> As far as mite bombings go, i think it causes a fairly good spike in mite numbers pretty quickly. I've never tracked my hives for such a thing but these are things i have been told about the subject.


Thank you, hex0rz! Just to make sure, what exactly is "mite bombing"? Is it when mite-carrying bees from a collapsing hive move in, or when the bees rob an infested hive? Interestingly, the hive right next to the hive that is being OAV-ed has had no mites since mid-May (as seen by an occasional OAV).


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## baybee

dudelt said:


> ... Remember, OA after vaporization works for about 3 days. You do not want to immediately vaporize at the three day mark.
> ...


Thank you for the link, dudelt! I don't mind OAV-ing every 7th day because I think it's easier on the bees. This particular hive doesn't take it very well: the vaporizer tray was full of burned bees when I pulled it out. Apparently, they kept attacking it for the 2-1/2 mins it was inside. Next day, a dozen or two dead bees under the entrance and a hive agitated for one day.

If most of mites spend at least five days in phorecy and one OAV works for three days then it does make sense to space the vaporizations seven days apart to accumulate as many newly emerged mites as possible before subsequent OAV.


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## baybee

Update on the ongoing OAV cycle.

*1st OAV* (Aug 23): 600 mites over 5 days

*2nd OAV* (Aug 28): about 1000 over 6 days
1st day drop -- 350;
2nd day drop -- 350;
3rd day drop -- 120;
4th day drop -- 100.
5th and 6th didn't inspect.

*3rd OAV* (Sept 3):
1st day: 950 (including two days before)

This is today's SBB tray:








The mite drop is on the rise; now the progeny of mites that had entered the cells at the beginning of this OAV cycle (two weeks ago) is being killed. I wonder how many (new and old) mites successfully finish phoretic leg of their life cycle (however long it is) between two successive vaporizations. 

An increase in the mite drop with every new vaporization is not unexpected considering that infestation level grows exponentially so as vaporizations go on, they hit more recently emerged (hence more numerous) mites.


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## Kuro

Please keep monitoring, I’m interested to see how this turns out. If my bee math is correct, the mites which were under capped brood when you started the OAV cycle (8/23) have come out by 9/2, and were killed at the 3rd OAV. If your OAV is efficient enough, you should be a able to see a significant decrease of mite drop at your 4 th OAV (9/9? if you do every 6-day). 

When I did every 5-day OAV in mid-late January 2016 (a small amount of worker brood present), fallen mites counted at 72 h were “84, 130, 108, 23, 8” in one hive and “94, 88, 52, 18 and 9” in another, which made me believe the treatment worked. Unfortunately, in my case, this did not happen during 2016 summer-fall OAV.


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## baybee

Kuro said:


> ... If my bee math is correct, the mites which were under capped brood when you started the OAV cycle (8/23) have come out by 9/2, and were killed at the 3rd OAV.


Still not sure how exact this science is. If mites enter cells two days before they are capped plus 12 days of pupa stage, this gives 14 days of capped mites for workers, 16 for drones.

The question, of course, is when (and by how much) OAVs break the exponential growth of mite population. By day 16, all pre-OAV mites from drone cells will have emerged. Before that, for about the first two weeks of vaporizations, 16 days max, whatever frequency, the number of phoretic mites should increase roughly exponentially, by 15-20% per day. Meaning the mite drop doubles every five days for the first 14-16 days, which is something observed and discussed here on BS before.

16 days from Aug 23 is Sep 8 or 9, this is when my 4th vaporization is going to be (if I don't decide to switch to MAQs). Yes, I'll know if OAV works only in a week from today.


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## baybee

Update on the ongoing OAV cycle.

*1st OAV* (Aug 23): 600 mites over 5 days

*2nd OAV* (Aug 28): about 1000 over 6 days
1st day drop -- 350;
2nd day drop -- 350;
3rd day drop -- 120;
4th day drop -- 100.
5th and 6th didn't inspect.

*3rd OAV* (Sept 3):
1st day: 950 (including two days before 3rd OAV)
2nd day: 250

Surprisingly, only 250 mites after a record drop. Either the last vaporization was extra effective or fewer mites emerge on some days than others. Or after three vaporizations the mite load is already noticeably lower.


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## baybee

Update on the ongoing OAV cycle.

*1st OAV* (Aug 23): 600 mites over 5 days

*2nd OAV* (Aug 28): about 1000 over 6 days
1st day drop -- 350;
2nd day drop -- 350;
3rd day drop -- 120;
4th day drop -- 100.
5th and 6th didn't inspect.

*3rd OAV* (Sept 3):
1st day: 950 (including two days before 3rd OAV)
2nd day: 250
3rd day: 150

So far, after beginning of the cycle:

the first five days: 600
the second five days: 1000
the last four days: 1250

It is possible that there is very little brood because of the dearth, so the mite infestation level hasn't been growing exponentially.


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## Juhani Lunden

baybee said:


> Update on the ongoing OAV cycle.
> 
> *1st OAV* (Aug 23): 600 mites over 5 days
> 
> *2nd OAV* (Aug 28): about 1000 over 6 days
> 1st day drop -- 350;
> 2nd day drop -- 350;
> 3rd day drop -- 120;
> 4th day drop -- 100.
> 5th and 6th didn't inspect.
> 
> *3rd OAV* (Sept 3):
> 1st day: 950 (including two days before 3rd OAV)
> 2nd day: 250
> 3rd day: 150
> 
> So far, after beginning of the cycle:
> 
> the first five days: 600
> the second five days: 1000
> the last four days: 1250
> 
> It is possible that there is very little brood because of the dearth, so the mite infestation level hasn't been growing exponentially.


I don´t know how it is with OAV, but with OAD *mites keep on dropping for 2 weeks* after one single treatment.


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## baybee

Juhani, I have never seen my backyard colonies without brood, so OAD, which can only be applied once in a long while, isn't an option, I guess. 

When you say pre-winter "mite counts" in your notes, do you mean just counting mite drops or are they based on alcohol washes? It would be interesting to see the correlation between fall infestation levels of young bees and winter survival.


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## msl

Plenty of study's have done 3 weekly treatments of oad 
Maggi's restiance study followed a comeroal beekeeper who did oad 8x a year for 8 years


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## Juhani Lunden

baybee said:


> Juhani, I have never seen my backyard colonies without brood, so OAD, which can only be applied once in a long while, isn't an option, I guess.


What I meant was that is there a long time effect in OAV treatments (like in OAD)? If there is, there is no point doing it in so short intervals. It may well be that because it it vapour, there is no long time effect.


Years 2001-2008 I counted mites dropped with OAD
after that sugar roll shakes


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## baybee

Update on the ongoing OAV cycle.

*1st OAV* (Aug 23): 600 mites over 5 days

*2nd OAV* (Aug 28): about 1000 over 6 days
1st day drop -- 350;
2nd day drop -- 350;
3rd day drop -- 120;
4th day drop -- 100.
5th and 6th didn't inspect.

*3rd OAV* (Sept 3):
1st day: 950 (including two days before 3rd OAV)
2nd day: 250
3rd day: 150
4th and 5th day didn't unspect (assumed about 100/day)

*4rd OAV* (Sept 8):

48-hr mite drop: ~750


So far, after beginning of the cycle mite drop:

days 1-5: 600
days 6-10: 1000
days 11-15: 1450
days 16-17: 750

Found two piles of some whitish debris, had never seen it before; hope it's just OA crystals caked after a few days on the tray:


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## Kuro

Hmm, I thought the majority of mites were exposed to OA during your first three vaporizations and I expected to see significant decrease after 4th.... If I were you I would do 5th and if 48hr drop is still >50, give up OAV and switch treatment method.

When I did OAV through the screen bottom, I often saw debris like that where the vaporizer head was. Probably OA crystalized on the screen and later dropped onto the mite board (I have not seen the debris after I quit doing OAV through screen).


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## JWChesnut

Those are really high numbers. In my 2015 and 2016 experience, where I attempted to replace an August Apivar treatment with OAV, I saw the same pattern. Simply not enough kill to break the "epidemic" cycle. The hives that had OAV in May had reduced mite numbers all summer and responded well. The hives that had spiking populations of mites, I couldn't get ahead of the infection with OAV.

I would go directly to Apivar with the numbers you are reporting. The OAV can be retried as a "tonic" in the spring and summer, and see if it reduces the growth curve sufficiently to manage less seriously compromised hives.


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## baybee

Update on the ongoing OAV cycle.

*1st OAV* (Aug 23): 600 mites over 5 days

*2nd OAV* (Aug 28): about 1000 over 6 days
1st day drop -- 350;
2nd day drop -- 350;
3rd day drop -- 120;
4th day drop -- 100.
5th and 6th didn't inspect.

*3rd OAV* (Sept 3):
1st day: 950 (including two days before 3rd OAV)
2nd day: 250
3rd day: 150
4th and 5th day didn't unspect (assumed about 100/day)

*4rd OAV* (Sept 8):

48-hr mite drop: ~750
3rd day: 150

Total drop:
days 1-5: 600
days 6-10: 1000
days 11-15: 1450
days 16-18: 900


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## baybee

Kuro said:


> Hmm, I thought the majority of mites were exposed to OA during your first three vaporizations and I expected to see significant decrease after 4th.... If I were you I would do 5th and if 48hr drop is still >50, give up OAV and switch treatment method.


The first three vaporizations took 11 days (Aug 23 -- Sept 3), which isn't long enough for the pre-OAV mites to emerge. I guess in my case, the fourth vaporization kills the progeny of the remaining pre-OAV mites (emerged between the 3rd and the 4th vaporizations, that is between days 11-16), which still should be quite numerous. 

Even though the exponential growth is stopped, I'm sure after the fifth it will be higher than 50/48hr. The temps are back to mid seventies, so I guess it's time for MAQs.



> I would go directly to Apivar with the numbers you are reporting.


I don't see how Apivar can be used here with almost continuous nectar flow. Apivar strips have to stay in for six weeks, plus two weeks before supers are allowed in. Eight weeks from now is end of October. 

What to do with the surplus honey in the brood nest and the honey collected after Apivar has been in? Harvest and then feed it back to the bees or compost it?

Would be interesting to see how after-OAV mite drop translates into alcohol washes of nurse bees. 

If those ~1000 mites, which dropped after the fourth OAV, were phoretic in a 50,000 bee colony, then, assuming half of them were on nurse bees (~1/5 of the total population), infestation level is about 500/10,000=5%, which translates into 15 mites/300 bees in an alcohol wash.


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## JWChesnut

My bees eat honey back to bare cells September - November. There is not a drop left.


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## baybee

JWChesnut said:


> My bees eat honey back to bare cells September - November. There is not a drop left.


What happens after November, new flow or feeding? To free up some space in the hive, I removed a deep full of honey early December last year; and, as seen a week ago, the bees still draw foundationless comb and bring nectar. Not sure if Apivar would be a good idea now, leaning towards MAQs.


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## shinbone

baybee said:


> Update on the ongoing OAV cycle.
> 
> 
> Total drop:
> days 1-5: 600
> days 6-10: 1000
> days 11-15: 1450
> days 16-18: 900



I think the more interesting question is how a hive with this many mites not already die? The mites must be a strain of mites that carried a relatively small virus load.


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## odfrank

Wait until some colder rainy weather comes. You'll see virus's at their finest. The hives look fabulous well into November. By Christmas they are dropping like flies.


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## baybee

shinbone said:


> I think the more interesting question is how a hive with this many mites not already die?


Well, I don't know the actual mite load for this hive. It's quite possible that if I had done an alcohol wash before this OAV cycle, the mite count would have been below treatment threshold. Alcohol washes only catch phoretic mites, while about four times as more mites are sealed with brood. Mite drops after OAV include both phoretic and newly emerged mites. 

Treatment threshold for alcohol washes is 5/300, times five gives 25/300. This is in the ball park of my rough estimate of an upper bound for the mite load based on after-OAV mite drops. It would be interesting to see how related are the counts from alcohol washes, OAV, and sticky boards.

I don't think this hive is as bad as this (natural mite drop, mite control guide from U of Florida):


> The treatment threshold is 60 mites on the screen per day. For example, screen left in colonies for 3 days and having 180 mites (an average mite fall of 60 mites per day), thus reaching the economic threshold to initiate mite control.


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## Kuro

baybee said:


> Well, I don't know the actual mite load for this hive.


If you treat your hive with full-dose MAQS and keep counting mite drop for ~2 weeks you may get a good estimate of mite# at the time of MAQS treatment. When I did MAQS on my hive in mid September 2 years ago, I counted ~2500 mites over 14 days. Sugar roll shortly before the treatment showed ~3% infestation. It was not a small nor a huge colony (Carniolan in double 8-frame deeps) and overwintered fine, after a round of OAV in January.


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## baybee

Mite drops for the last OAV cycle.

*1st OAV* (Aug 23): 600 mites over 5 days

*2nd OAV* (Aug 28): about 1000 over 6 days
1st day drop -- 350;
2nd day drop -- 350;
3rd day drop -- 120;
4th day drop -- 100.
5th and 6th didn't inspect.

*3rd OAV* (Sept 3):
1st day: 950 (including two days before 3rd OAV)
2nd day: 250
3rd day: 150
4th and 5th day didn't inspect (assumed about 100/day)

*4rd OAV* (Sept 8):

48-hr mite drop: ~750
3rd day: 150
4th + 5th days: 160

Total drop:
days 1-5: 600
days 6-10: 1000
days 11-15: 1450
days 16-20: 1000

I stopped OAVs at this point and moved on with a full-dose MAQs. Lets' see how many mites have survived four vaporizations, which can give an idea of how efficient the OAV cycle was on this hive with brood. OAVs have definitely disrupted exponential growth of mites; will see soon by how much.


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## Bob J

baybee much appreciate you posting your results.... Good stuff!


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## baybee

Mite drops for the last OAV cycle followed by full-dose MAQS.

*1st OAV* (Aug 23): 600 mites over 5 days

*2nd OAV* (Aug 28): about 1000 over 6 days
1st day drop -- 350;
2nd day drop -- 350;
3rd day drop -- 120;
4th day drop -- 100.
5th and 6th didn't inspect.

*3rd OAV* (Sept 3):
1st day: 950 (including two days before 3rd OAV)
2nd day: 250
3rd day: 150
4th and 5th day didn't inspect (assumed about 100/day)

*4rd OAV* (Sept 8):

48-hr mite drop: ~750
3rd day: 150
4th + 5th days: 160

*Full-dose MAQS* (Sept 14): 
mite drop after first five days: ~1500

Total drop:
days 1-5: 600 OAV
days 6-10: 1000 OAV
days 11-15: 1450 OAV
days 16-20: 1000 OAV
days 22-27: 1500 MAQS

Judging by the massive mite drop after application of MAQS, it was a good idea to abandon OAVs and go ahead with formic acid. Obviously, four-five OAVs on this brooding hive wouldn't be sufficient for bringing mite infestation to a safe level. I used 2.5-3 grams of OA dihydrate for one vaporization and all of it sublimated.

What's interesting, late stage drone pupa (with colored eyes) or newly emerged drones made up about 80% of all casualties following application of MAQS. This hive seem to be raising a lot of drones which might have contributed to the infestation level.


----------



## sjj

baybee said:


> ...
> days 22-27 ...
> Judging by the massive mite drop after application of MAQS, ...


Better: 22 +12 days


----------



## IAmTheWaterbug

So, do you have any actual bees in your mite colony?


----------



## baybee

Mite drops for the last OAV cycle followed by full-dose MAQS.

*1st OAV* (Aug 23): 600 mites over 5 days

*2nd OAV* (Aug 28): about 1000 over 6 days
1st day drop -- 350;
2nd day drop -- 350;
3rd day drop -- 120;
4th day drop -- 100.
5th and 6th didn't inspect.

*3rd OAV* (Sept 3):
1st day: 950 (including two days before 3rd OAV)
2nd day: 250
3rd day: 150
4th and 5th day didn't inspect (assumed about 100/day)

*4rd OAV* (Sept 8):

48-hr mite drop: ~750
3rd day: 150
4th + 5th days: 160

*Full-dose MAQS* (Sept 14): 
mite drop after the first five days: ~1500
mite drop for the next six days: 600

Total drop:
days 1-5: 600 OAV
days 6-10: 1000 OAV
days 11-15: 1450 OAV
days 16-20: 1000 OAV
days 22-27: 1500 post-MAQS
days 28-33: 600 post-MAQS

It has been 11 days since MAQS application; so far, post-MAQS drop is 2200 (first five days: 1500; next six days: 600)


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## Juhani Lunden

I once counted about 8500 mites after one single OAD treatment in late October. The colony died in winter.


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## shinbone

Baybee - very interesting numbers. Thanks for the great info.


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## Kuro

Looking good, your numbers are fairly close to what I got before (daily count after full-dose MAQS, 9/15-10/3/15; 503, 173, 203, 151, 194, 206, 85, 101, 164, 168, 132, 167, 95, 16, 6, 5, 6, 5, 3).


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## dudelt

Baybee, you are the perfect example of why mite monitoring is so important. You did not mention that you did any regular monitoring other than counting the drops after a treatment and I am strongly recommending that you start. The lack of a monitoring program is only one of the issues you are facing. Randy Oliver was in town for a seminar a few weeks ago and one of his topics was why varroa is a bigger problem in the south than it is in the north. I do realize that you are not that far south. The basic idea was that the more days the bees have a sizable brood area, the more days the varroa have to be multiplying. It makes good sense. Another topic he covered and the more important one in your case is the issues beekeepers in the San Francisco area have with mites. Due to the organic mentality(?) in the area, there are a lot of small treatment free beekeepers/beehavers that make the surrounding area a very large mite bomb. This might be the problem you are running in to. While you are treating, your neighbors are not. Thus, you keep getting re-infested. With the number of mites you are dropping, they have to be coming in from outside of your hives.


----------



## baybee

Juhani Lunden said:


> I once counted about 8500 mites after one single OAD treatment in late October. The colony died in winter.


Juhani, an interesting number. There was probably no brood at that time, so all 8500 mites were phoretic on 20-30 thousand bees (or how many?). This translates into an infestation level of 25-40%, which, in a way, is the genuine infestation level, not the one estimated with alcohol washes.

I only hope that by late October this hive will have very low mite numbers.



Kuro said:


> Looking good, your numbers are fairly close to what I got before (daily count after full-dose MAQS, 9/15-10/3/15; 503, 173, 203, 151, 194, 206, 85, 101, 164, 168, 132, 167, 95, 16, 6, 5, 6, 5, 3).


Yes, the dynamics look similar. With that many mites dropping, the hive I've been busy treating still looks better than the one next to it last fall (which survived the winter). 



dudelt said:


> Baybee, you are the perfect example of why mite monitoring is so important. You did not mention that you did any regular monitoring other than counting the drops after a treatment and I am strongly recommending that you start.


I've never done alcohol washes, just watched natural mite drops because of the fear of killing unmarked queens. I suspect that, in this local micro-climate of cool afternoon ocean breezes and temperatures of very rarely above 70, hives have little chance of re-queening themselves. Young queens from queen cells never started laying in my hives.

With OAV having been inefficient in hives with brood, artificial brood breaks followed by a couple of vaporizations might be an option. One hive that went queenless for a few weeks in the summer is now virtually mite-free after just two OAVs. 



dudelt said:


> ... Another topic he covered and the more important one in your case is the issues beekeepers in the San Francisco area have with mites. Due to the organic mentality(?) in the area, there are a lot of small treatment free beekeepers/beehavers that make the surrounding area a very large mite bomb. This might be the problem you are running in to. While you are treating, your neighbors are not.


I guess keeping infestation level in check in this climate takes a good deal of area-specific knowledge and experience, of which I'm only beginning to scratch the surface. I suspect that many local backyard beekeepers, organic-minded or not, just aren't prepared for this kind of dedication. I've heard that (at least) one of the nearby backyard beekeepers keeps buying several packages every spring.


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## baybee

Today is 17 days since application of MAQS; about 150 mites dropped for the last six days. Almost all mites counted today seemed to have fallen from two central frames as judged by their locations on the bottom board.

Mite drops for the last OAV cycle followed by full-dose MAQS.

*1st OAV* (Aug 23): 600 mites over 5 days

*2nd OAV* (Aug 28): about 1000 over 6 days
1st day drop -- 350;
2nd day drop -- 350;
3rd day drop -- 120;
4th day drop -- 100.
5th and 6th didn't inspect.

*3rd OAV* (Sept 3):
1st day: 950 (including two days before 3rd OAV)
2nd day: 250
3rd day: 150
4th and 5th day didn't inspect (assumed about 100/day)

*4rd OAV* (Sept 8):

48-hr mite drop: ~750
3rd day: 150
4th + 5th days: 160

*Full-dose MAQS* (Sept 14): 
mite drop after the first five days: ~1500
mite drop for the next six days: 600
drop for the next six days: 150

*Total drop:*
days 1-5: 600 OAV
days 6-10: 1000 OAV
days 11-15: 1450 OAV
days 16-20: 1000 OAV
days 22-27: 1500 post-MAQS
days 28-33: 600 post-MAQS
days 33-39: 150 post-MAQS


It has been 17 days since MAQS application; so far, post-MAQS drop is 2300 (first five days: 1500; next six days: 600; next six days: 150)

Will do OAV on this hive in a few days to see how many phoretic mites there are.


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## baybee

I decided to stop doing second series of OAVs and put another full-dose MAQS into this hive today, Nov 20th. This hive has two full deeps of bees, brood is seen through the seams on top of the second deep. 

Since late August this hive has been treated:

4 OAVs 5 days apart: Aug 23 - Sept 8;
full-dose MAQS: Sept 14;
5 OAVs 5 days apart: Oct 25 - Nov 14;
full-dose MAQS: Nov 20.

The 48 hr drop after the fifth OAV (of the second series) on Nov 14 was about 150, which was a great reduction from ~600 after the first on Oct 25. However, still too high considering that the bees are brooding and bring pollen and nectar. Total drop after five OAVs of the second round was about 1500 (600, 300, 200, 150, 150).

The weather forecast had changed to the highs of 65-70F for the next five days, so in went full-dose MAQS.

This is what the two MAQS pads, that I put in the hive on Sept 14th, looked after ten weeks inside:









-- dry and propolized, but pretty much untouched by the bees.


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## Kuro

Wow, so it looks like you do not have a winter break in San Mateo and you just have to keep fighting. I wonder what commercial beekeepers do in your area. 
My bees do not get rid of MAQS pads either, so I usually take them out after a few weeks.


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## odfrank

>I wonder what commercial beekeepers do in your area

Not all of us here have OCD when it comes to mites.


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## Kuro

odfrank said:


> Not all of us here have OCD when it comes to mites.


With only a few hives in my backyard, it will take many years for me to grow out of the OCD.


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## baybee

Kuro said:


> ... I wonder what commercial beekeepers do in your area.


I've heard of them using MAQS, OA dribble, Apivar; have yet to hear of a commercial beekeeper doing OAV here. I would for sure just use Apivar, if there were no nectar flow. But I want to try local eucalyptus honey, which can't be done without keeping the hives healthy and the supers on.

In our "coastal ridges" microclimate, virgin queens have failed to mate; you lose a hive, you buy a new one. Maybe I should find a spot for mating nucs somewhere 15-20 miles down the I-280.


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## Charlie B

I used to be OCD on mites too but I have discovered that my bees live as long without all the treating. Not that I’m anti-treatment, I’m not. I have too many hives to run around and do all that. I’m lazy.


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## gww

I haven't got too many hives and have not been keeping bees for 40 years but have the lazy part down pretty good. I think about mites but don't get out of my easy chair and do any thing about them yet.
Cheers
gww


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## Charlie B

Oh gww, you screwed up now:no: Ollie’s been keeping bees for 47 years, not 40. You will soon be corrected by him on that. :lpf:


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## gww

> Oh gww, you screwed up now:no: Ollie’s been keeping bees for 47 years, not 40. You will soon be corrected by him on that. :lpf:


Opps:doh:
Cheers
gww


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## baybee

This year's treatments so far:

*4 OAVs* 5 days apart: Aug 23 - Sept 8;
full-dose *MAQS*: Sept 14;
*5 OAVs* 5 days apart: Oct 25 - Nov 14;
full-dose *MAQS*: Nov 20.

Post-MAQS mite drops starting Nov 20:

*first 72 hrs*: around 1000;
*next 48 hrs*: around 50.

The high drop for the first three days suggests that MAQS has probably worked; however, the extremely low drop for the next 48 hrs was either because very few bees have emerged during these five days, or the pads due to age weren't releasing enough acid to reach the sealed brood.

I have kept the box with MAQS in the freezer all the time; it is still good for a few months:









While installing the pads or later at the entrance, I didn't smell any FA, which wasn't the case before. Also, the activity of the bees was only disrupted for half a day or so; around 100 dead bees, but only a few young larvae/pupae, quite a change from the first treatment.


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## Kuro

First 72hr/next 48hr count in my hands were 36/5 (8/11/17, full-dose), 98/32 (8/11/17, full-dose), 879/345(9/14/15, full-dose), 898/227(10/4/15, the first of half-dose), 386/105 (10/20/15, the 2 nd of half-dose). Your 48hr number seems low but as you said, probably less bees are emerging now even in your location, and your 2 nd round of OAV may have significantly brought infestation level lower. 

I also keep MAQS in the freezer. The smell of formic acid is really bad when I open the package, but not so much by the time I put it in the hive (in 5 - 10 min). 

About dead bees, when I treated a hive with a half dose MAQS on 10/4/15(high temp 68F), I saw dead bees/larva outside the bottom entrance on the next day. Two weeks later I put the 2nd dose (high temp 59F) and found no dead bees on the next day. I thought it was temperature effect.


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## baybee

This year's treatments so far:

4 OAVs 5 days apart: Aug 23 - Sept 8;
full-dose MAQS: Sept 14;
5 OAVs 5 days apart: Oct 25 - Nov 14;
full-dose MAQS: Nov 20.

Post-MAQS mite drops starting Nov 20:

first 72 hrs: around 1000;
next 48 hrs: around 50;
*last 72 hrs: *around 50.

The mite drop is much lower now but still substantial: it is either the residual effect from MAQS, or natural. What's encouraging is that among dark ruby mites I see paler-colored ones, which supposedly are falling off emerging bees.

Thanks, Kuro! Yes, the temps during the follow-up application of MAQS were a good 10-20 degrees lower.

Will watch it for a week or so, then gauge the infestation with an OAV.


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## Lauri

IAmTheWaterbug said:


> So, do you have any actual bees in your mite colony?


Dang! Right? 
Or is my perspective on a bad mite load way off?


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## baybee

This year's treatments so far:

4 OAVs 5 days apart: Aug 23 - Sept 8;
full-dose MAQS: Sept 14;
5 OAVs 5 days apart: Oct 25 - Nov 14;
full-dose MAQS: Nov 20.

Post-MAQS mite drops starting Nov 20:

first 72 hrs: around 1000;
next 48 hrs: around 50;
next 72 hrs: around 50;
*last 5 days*: 120.


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## baybee

This year's treatments so far:

4 OAVs 5 days apart: Aug 23 - Sept 8;
full-dose MAQS: Sept 14;
5 OAVs 5 days apart: Oct 25 - Nov 14;
full-dose MAQS: Nov 20.
Post-MAQS mite drops starting Nov 20:

first 72 hrs: around 1000;
next 48 hrs: around 50;
next 72 hrs: around 50;
next 5 days: 120;
*last 3 days:* around 50.

The mites keep dropping. In contrast, the other hive, just a foot away and about the same size, has shown very low mite drops all along, even though it had only been treated with OAV. I guess it has something to do with the genetics because the bees look and behave differently.


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## Mike Gillmore

baybee said:


> I guess it has something to do with the genetics because the bees look and behave differently.


That's interesting. What behavior differences are you noticing in the hive with low mite drops? 

Also, what is going on inside the hives? Does the amount of brood appear similar, or do you notice a difference in the two?


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## baybee

Mike Gillmore said:


> ... Also, what is going on inside the hives? Does the amount of brood appear similar, or do you notice a difference in the two?


Two-three weeks ago the low-drops hive had brood on three frames in the top deep, shaped like a half of a football, with the other half supposedly in the lower deep.
Two weeks ago, the problem high-drop hive had sealed brood visible through the seams in the top deep; not sure how that compared to the other hive. Both hives have crowded orientation flights at the same days.

The apparent differences are:

*Hive W:* yellowish bees; very testy and don't like people around the hive; faster in expanding the colony and in making honey; tend to start foraging later in the day when it's warmer and call it earlier; used to be a three-deep hive in the summer.

*Hive E:* greyish bees; indifferent to the point that no smoke is necessary; slower in expanding and in making honey; start foraging earlier and finish later in the day; never grew beyond two deeps.

I guess it's pretty obvious which hive is mite-ridden. Not sure though if these differences (except the color) are caused by the genetics.


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## baybee

The mite drop from the problem hive now, three weeks after application of full-dose MAQS, is next to nothing. The natural drop for the hive next to it, to which I only applied OAVs a month ago, is zero. Most probably due to the relatively warm and dry weather and a lot of available food the brood nest size has doubled for both hives in the last three weeks, which definitely means more mites. 

Here in this clip is the problem hive. I'm sure the soundtrack is the bees' favorite, if not all-time then definitely this time of year.

Here are two more slow motion clips, shorter and longer, showing bees at the entrance.


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## Kuro

:applause::applause:


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## Fivej

Beautiful video. Mesmerizing. J


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## baybee

Mite treatment this Fall:

4 OAVs 5 days apart: Aug 23 - Sept 8;
full-dose MAQS: Sept 14;
5 OAVs 5 days apart: Oct 25 - Nov 14;
full-dose MAQS: Nov 20

To test mite load after the full-dose MAQS about a month ago, did OAV on the problem hive on Dec 28th: 72 hr drop is 310.

Not sure how much brood there is in this hive now; what's interesting is that most of the dead mites on the SBB tray were right underneath the ever-present cluster on the slatted rack. Ever since I installed slatted rack a year ago there is a soft ball-sized cluster (marked pink) under the slats next to the 3" entrance (marked blue).















Does this mean that most of the dead mites were phoretic that have fallen from the foragers clustered on the slatted rack? The bees have been actively foraging for the last month or so due to warm, around 60F, weather.


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## Lauri

Man, I am SO grateful for my cool winter and extended broodless period! 

I don't know how folks in warm weather climates do it. It's got to be a constant struggle with no optimal time to treat.

I don't know how the commercial guys manage it. What pressure.


----------



## baybee

Did another OAV on this "problem" hive this morning. The bees went berserk, I had to run for safety after OAV was finished and I pulled the wand out. I started with a pan full of OA crystals and pulled out a pan full of caramelized bees -- they really hate OAVs:











Lauri said:


> I don't know how folks in warm weather climates do it. It's got to be a constant struggle with no optimal time to treat.


 I guess not every single hive fails to control mites. For some reason (genetics?), the hive right next to this "problem" hive has had a very low mite load since its start -- without any MAQS and with just two series (4x, 4-5 days apart) of OAVs, late summer and late fall. I wish I could propagate this genetics but my virgin queens have been failing to mate successfully so far due to strong coastal winds and fogs; now is the best time of year: quiet and clear.


----------



## JRG13

I had some hives similar like that, except I thought I was getting burned by the gadget one time, but it was a stinger in my finger....


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## baybee

Looks like "the problem" hive is mite-free now. Initial mite drop following the Dec 28th OAV was high, but after the second OAV on Jan 1st only a few mites dropped, and after the third on Jan 6th -- none. I suspect that, for whatever reason, this hive has no brood, which is what OAV is designed for. 

Total treatment:
4 OAVs 5 days apart: Aug 23 - Sept 8;
full-dose MAQS: Sept 14;
5 OAVs 5 days apart: Oct 25 - Nov 14;
full-dose MAQS: Nov 20
3 OAVs 4 days apart: Dec 28 - Jan 6.


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## 1102009

baybee said:


> Not sure how much brood there is in this hive now; what's interesting is that most of the dead mites on the SBB tray were right underneath the ever-present cluster on the slatted rack.
> 
> Does this mean that most of the dead mites were phoretic that have fallen from the foragers clustered on the slatted rack? The bees have been actively foraging for the last month or so due to warm, around 60F, weather.


Without treatments it´s exactly the same picture, mite downfall is under the cluster and it´s the dead mother mites falling down after the new bees hatch. The daughters are fixed on the young bees.
To test if your treatments worked you have to know if the mites are daughter mites or do an alcohol wash to see how many phoretic mites you have left after the young bees emerged.
Testing with OAV should distribute mite downfall more if the bees are active. IMO.
But since you repeated the OAV it should have worked. Very interesting thread, thank you for updating.

Amazing video! There was some grooming done. Do your bees always have drones this time of year?


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## baybee

baybee said:


> Total treatment:
> 4 OAVs 5 days apart: Aug 23 - Sept 8;
> full-dose MAQS: Sept 14;
> 5 OAVs 5 days apart: Oct 25 - Nov 14;
> full-dose MAQS: Nov 20
> 3 OAVs 4 days apart: Dec 28 - Jan 6.



Because this "problem" hive, treated as shown above, has stopped dropping mites since late December I suspected that it's lost its queen. Well, from what I see the hive replaced the queen but the new queen expectedly failed to mate and has been laying drones for a a while now. All brood I could find in this hive is drones. Alternatively, the old queen has run out of sperm, which is a possibility according to the books. 

Not 100% sure but I believe it is a new virgin drone-laying queen, and not laying workers, because the brood pattern is mostly solid, and because I could see fresh eggs with the same solid pattern at the bottoms of cells one egg per cell. 

What's interesting is that drone brood is both in drone comb and in worker comb. 

There's still a lot of bees in the hive.

These are two side of a 1/3-plastic foundation frame, there are two more frames similar to this:

















If this is a drone laying queen, can this hive minus the queen be combined with another hive? Or giving them frames of brood is an option too?


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## snl

Lauri said:


> Man, I am SO grateful for my cool winter and extended broodless period!
> 
> I don't know how folks in warm weather climates do it. It's got to be a constant struggle with no optimal time to treat.


Since OAV is basically a flash treatment, it's multiple treatments for me. As you've experienced Lauri with the ProVap, treatments are now fast and easy....


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## odfrank

>Total treatment:
4 OAVs 5 days apart: Aug 23 - Sept 8;
full-dose MAQS: Sept 14;
5 OAVs 5 days apart: Oct 25 - Nov 14;
full-dose MAQS: Nov 20
3 OAVs 4 days apart: Dec 28 - Jan 6.

"*Cutting off* the *nose* to spite the *face*" is an expression to describe a needlessly self-destructive over-reaction to a problem: "Don't *cut off* your *nose* to spite your *face*" is a warning against acting out of pique, or against pursuing revenge in a way that would damage oneself more than the object of one's anger.


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## Charlie B

odfrank said:


> >Total treatment:
> 4 OAVs 5 days apart: Aug 23 - Sept 8;
> full-dose MAQS: Sept 14;
> 5 OAVs 5 days apart: Oct 25 - Nov 14;
> full-dose MAQS: Nov 20
> 3 OAVs 4 days apart: Dec 28 - Jan 6.
> 
> "*Cutting off* the *nose* to spite the *face*" is an expression to describe a needlessly self-destructive over-reaction to a problem: "Don't *cut off* your *nose* to spite your *face*" is a warning against acting out of pique, or against pursuing revenge in a way that would damage oneself more than the object of one's anger.


:applause:


----------



## baybee

odfrank said:


> ...
> ...
> 
> "*Cutting off* the *nose* to spite the *face*" is an expression to describe a needlessly self-destructive over-reaction to a problem: "Don't *cut off* your *nose* to spite your *face*" is a warning against acting out of pique, or against pursuing revenge in a way that would damage oneself more than the object of one's anger.


 Well, I guess when you are a beginner it's hard to come up with an appropriately measured response to a problem. I've learned another lesson.

However, what I'm still not sure about is if this is the old queen turned drone layer or a new virgin queen. I've read an opinion here that a queen that has not mated never lays.

I'm leaning towards virgin queen that has never mated. This is because this hive has definitely had a brood break around the New Year, which explains no mites after the last OAV series, and because this winter has been too warm for a healthy queen to have a brood break.


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## msl

yep, cut the queen instead of your nose 

@ snl.. yes fast easy and as this thread shows.... useless when brood is on, the PV100 is a great bit of kit, but not a magic wand 

Instead of crowing, its time to promote effective and sustainable use, tell people to hive tool test that POS queen, popper timed OAV TX with the PV110, and much $$ and time would have been saved.

no matter how much or little you send on a vaporizer, its no replacement for actual beekeeping


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## baybee

msl said:


> yep, cut the queen instead of your nose
> ...
> 
> Instead of crowing, its time to promote effective and sustainable use, tell people to hive tool test that POS queen ...
> ...


Interesting. If replacing that "less than perfect" queen was the only solution to this particular hive's mite infestation, then at what point in my treatment sequence should that have become clear? 

Could it be easier to force a brood break by caging the queen before OAVs? Or could it be that too much drone comb (like half foundation frames) in the hive has made the treatments less effective?


----------



## rwurster

3 oav 5 days apart should have gotten rid of the problem. Something went wrong somewhere.


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## baybee

If that brood pattern is produced by a new queen then this means that, in order to start laying anything, she must have mated some time early January. Not successfully, but she did what she could. 

Question: With the weather getting warmer, should I squeeze this hive into a nuc and give them open brood for them to try to raise another queen? And then again, until they get themselves a laying queen or until queens for sale are available here, which is around late April?


----------



## baybee

Deleted duplicate.


----------



## msl

> at what point in my treatment sequence should that have become clear?


at the point the mites were significantly higher then your other hives asumeing they were manganged the same 


> Could it be easier to force a brood break by caging the queen before OAVs?


yes or











> could it be that too much drone comb


yes, Wilkinson and Smith (2000, 2001)-_"As many mites are emerging from 50-60 drone cells as from 1000 worker cells"_
the means a 1/2 frame of drone brood could produce more mites then all the worker brood. Were your other hives sat up this way as well?
Cuting out that comb would be my 1st step in a problem hive, not just for mite controal, but to stop the spread of poor genetics.


----------



## baybee

msl said:


> ...Wilkinson and Smith (2000, 2001)-_"As many mites are emerging from 50-60 drone cells as from 1000 worker cells"_
> the means a 1/2 frame of drone brood could produce more mites then all the worker brood. Were your other hives sat up this way as well?


Well, my other hive had no drone comb at all, except for burr comb between frames, and it has been virtually mite free since last spring. I suspect too much drone comb after OSB might have gotten mites out of control.


----------



## larrypeterson

I hope this is the appropriate place to post this update.

For two years now I have been treating with OAV, This is the start of the third year and I have treated twice so far this year. My "Oxyvap" made me a believer in the effectiveness of OAV. Last year I followed Randy Oliver's use of food grade glycerin and dissolved OA on paper towls. I also took it one step further and dissolved OA into the glycerin and applied to with a fogger. We had a very mild winter so I fogged them in February but this time I prepared my OA a little differently. I used a 1 quart jar and added about 1 pint of glycerin. I then heated it slowly in a pan of hot water and added all the OA I could get to go into solution. I stirred it until just a bit of OA residue started forming on the bottom. After cooling, I poured it out into a pint bottle from the clear top part of the quart. I fogged with one squeeze per box and was able to finish in just a very short time. I just completed the second application of the 3 seven day cycle yesterday. I have not observed any negative affect on the bees. I check for mites by pulling out drone larva and looking for the little red spots.

After last years emergence of infection, thought to be carried in by mites, I am being more aggressive with my treatments. My attempts at "treatment free" beekeeping have resulted in more dead bees. So, for the time being, I am treating. This method is my own concoction and I in no way expect anyone else to accept it nor do I advocate it for anyone else. I am trying to add to the body of knowledge and to, in some small way, assist others if they want to venture into uncharted waters.

I wish you well, LP


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## msl

This isn't uncharted waters, the rocks here are well known.
OA breaks down in heated glycerin in to formic acid 
Alcohol eats the pump seals
Water dosen't dissolve enough OA
OA won't dissolve in FGMO 
Aside from the above issues the main problem seems to be that OAV creates super fine dust particals that get every were in the hive as shown on this bee 








Best guess is when you run it thew the fogger with water/alcohol it apears you are boiling it out of solution and blowing the (much larger) crystals out the end of the fogger before they are heated to the point the OA can sublimate. 

here is a post from 13 years ago http://www.beesource.com/forums/showthread.php?204835-OXALIC-ACID-IN-A-FOGGER
it follows a common theam with the mountan of posts on the subject here on BS.... some one trys it, likes how easy it is, when mite counts are asked for the thread ends with no follow up report 
those who have reported back have all have had poor mite control and stoped using it 
The long and short is if it worked, every one would be doing it by now. This is a big case of people forgetting history and repeating it


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