# mites after multiple OAVs



## Mike Gillmore (Feb 25, 2006)

The infestation may have been terrible when you first started the treatments. Sounds like you had a high phoretic mite kill rate after your first treatment, but there may have been a tremendous amount of capped brood that was infested with mites and they went untouched by the OAV. The brood damage was already done and sometimes it takes weeks to see the results, such as crawlers and DWV. 

If your hives are actively brooding you may want to consider a formic acid treatment at this time so you can get to all the mites under the cappings as well. OAV is good, but the time of year it is used is important. It is most effective when the hive is broodless or really cutting back on their brood, such as a mid summer brood slowdown during a dearth.


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## beemandan (Dec 5, 2005)

I would not do oav treatment cycles indefinitely. If there is going to be any resistance to it....that will surely speed the process up.

What sort of vaporizer are you using?


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## baybee (Jan 10, 2016)

Appreciate the responses! Yes, the hive (I only have one: two brood boxes, one honey super -- all deeps) has brood. I have been thinking about half-dose of MAQS in addition to OAV but don't want to end up with a queenless hive. What are the chances with the temperature staying within 50 to 70? 

Is there such a thing as mites resistant to OA? I use a commercial vaporizer.


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## Zephyr (May 4, 2016)

Watch yourself there; if there's medication then there can be resistant strains. Eventually we'll probably face Apivar resistance. Whatever mites live through these treatments will be harder to kill with OA next time. Then their offspring are already equally hard to kill and keep living to keep building resistence then breed to spread that new improved resistance. When you stop OA, mix it up next treatment for the sake of the rest of us! <3


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## Mike Gillmore (Feb 25, 2006)

I'm not really familiar with your weather there in San Mateo, but if you still have drones coming and going then your colony should be able to replace your queen, if by chance the MAQS injures her and she is replaced. Perhaps someone in the area could advise on that question. 

I've been using OAV judiciously for several years. I have seen no evidence so far that mites have become resistant to it. But, as beemandan mentioned, overuse and improper use "could" speed up that process if it is going to happen. If OAV has to be used over and over again, week after week after week, it's not the correct treatment to be used at that time. Just my opinion, with a pinch of common sense.


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## Branman (Aug 20, 2003)

Also there's a chance that your bees are robbing out sometime else's dead outs and picking up all the mites that hive has left behind.


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## beemandan (Dec 5, 2005)

baybee said:


> I use a commercial vaporizer.


You have one of those blower driven, vaporizers that the commercial guys use to treat a hundred hive yard? How many hives do you have again?? Maybe we have a different definition of commercial. I take it that you don't want to tell us the brand or model. 
I'm thinking that you ought to leave those bees alone until spring before you kill them too.


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## Gumpy (Mar 30, 2016)

Check your sealed brood for drones. Open some up and see how bad the mites are in them. If they are infested, cut them all out and discard them. 

I've been fighting mites for 6 or 7 weeks now. I found a patch of drone brood that was infested with mites. Two or three in each cell. This was after eight or nine OAV treatments at 5 day intervals. Ultimately I doubled the dosage and switched to a three day interval and I'm finally seeing improvements in the mite drop counts. Two more and I think I'll call it good.


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## Aroc (May 18, 2016)

I've always understood that OA's action on a mite isn't chemical but rather a physical process and as a result any 'resistance' would be evolutionary and take thousands of years to develop. Much akin to a football player developing a resistance to concussions. It's been used for decades and as far as I know hasn't been any indication of resistance developing anywhere. My concern with many multiple treatments wouldn't be restistance but potentially harmful effects on the bees themselves.


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## MicandTessa (Apr 1, 2016)

Weather in the bay area will be good for the next three weeks highs in the 60s or 70s. The problem with going to MAQS this time of year is that you have to have lots of ventilation and in our area that means robbing potential. You could end up killing all the mites only to have your weaken hive robbed out.


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## beemandan (Dec 5, 2005)

Aroc said:


> Much akin to a football player developing a resistance to concussions.


If you went around bumping every person on the head with enough force to cause a concussion and out of the billions of people on earth you'd find some that were less sensitive. If you then used those people as the primary gene source human reproduction....you'd skip a few million years of evolution. In my opinion.


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## razoo (Jul 7, 2015)

beemandan said:


> If you went around bumping every person on the head with enough force to cause a concussion and out of the billions of people on earth you'd find some that were less sensitive. If you then used those people as the primary gene source human reproduction....you'd skip a few million years of evolution. In my opinion.


Lol!
Unless you came back three days later and bump them again! That should knock them off more permanently! 

Suggest you move over to 3 day intervals. The mites are in the phoretic phase for 4 to 5 days, before going under the capped larvae in order to breed. Hit them with OAV before they go into capped brood cells, hence every three days.


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## Delta Bay (Dec 4, 2009)

I keep hearing this 4 to 5 day phoretic stage. From my reading that is only an average, a better range would be 3 to 7 days and some outside that. Oxalic has always been a treatment recommended during the broodless time or when very little brood is in the colony. It makes no sense to me to spend so much time using a treatment over an extended time frame when the best time is during a broodless time. It's not such a hard thing to induce a broodless stage outside when you need brood production and then treat with one shot. How can gasing your bees 3 days apart over months be a good thing?


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## Eduardo Gomes (Nov 10, 2014)

It seems that no one knows under natural conditions which is exactly the duration of the phoretic period however I let this quote: "The duration of the phoretic phase (Phoretic Varroa = on adult bees) between 2 reproductive cycles is variable. An impregnated young female must necessarily mature in phoresy around 7 days (from 5 to 14) before it can infest a cell at the right stage and carry out its first reproductive cycle. *However, the phoretic phase is not vital subsequently and depends mainly on the availability of nearby cells to be infested at the right stage of development.*" source: http://www.veto-pharma.com/products/...-varroa-mites/

Are we selecting the mites with phoretic periods of one day or even a few hours with the use of frequent OAV treatments?


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## Eduardo Gomes (Nov 10, 2014)

"Several studies focusing on the phoretic phase have shown that it seemed to have no aim for the parasite other than providing transport between reproduction sites [11]. Therefore, it could be suppressed without having any visible impact on the mite reproduction in natural conditions [12]. The phoretic mites are more attracted to nurse than forager bees probably because they carry them to their reproduction site [13,14], but the type of bee hosts during the phoretic phase could further influence the mite life cycle by impacting its reproduction. In addition, *as the phoretic mites stay on adult bees for a variable amount of time, from one to ten days or more *[15], the possible impact of the length of the phoretic phase on nurse bees is of great interest."

source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4838260/#pone.0153482.ref015

If if some mites have a phoretic period of one day it will be necessary to rethink the treatment with OAV in the presence of brood, IMO.


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## Mike Gillmore (Feb 25, 2006)

Delta Bay said:


> How can gasing your bees 3 days apart over months be a good thing?


That is a great question. Do we really understand the ramifications of long term excessive OAV treatments? 

That will no doubt reduce the mite load, but what price will be paid to achieve that goal. How much will repeated acid vaporization treatments alter the ph and internal hive environment? How much cumulative damage will the bees experience? 

I know they can tolerate a normal battery of OAV treatments, but what condition will the bees be left in after constant exposure to acid over an extended period of time? I guess we'll know in a couple of months when we see the survival rate of these hives.

Who knows, it may create a new strain of bees. Bleached bees, with just a tint of amber color remaining.


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## Arnie (Jan 30, 2014)

Mike Gillmore, snl has a couple experimental hives that he has vaporized every time he goes to the bee yard to do some work. For two years running. According to him it's about every 7 to 10 days for two years. He says he does it just to see what will happen. He reports that the bees are thriving and the original marked queens are still alive and well.

I know it isn't definitive, but it does give us some measure of well being that we aren't dooming the bees and queens to an early grave if we have to extend the fall treatment regimen to 5 or 6, or more, treatments to get the mites under control.


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## Mike Gillmore (Feb 25, 2006)

That's good to know, Arnie. Can't dispute the results. I am an advocate of OAV and it has worked extremely well for me for some time now, but I'm just a bit nervous about overuse on a few different levels. I won't be going in that direction with my hives. If the mite levels are that bad, and it's during the brooding season, I just don't think OAV is the practical answer. Just my opinion, and we all have them.


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## beenoob (Jun 16, 2016)

I hope I am not hijacking this thread, but I have pretty much the same exact question. At what point is it enough, how many drops should we be seeing that tells us ok its enough OAV. I have treated 4x every 6-7 days and still seeing a drop on one of my hives at about 60-70 mites. Should I continue treating weather permitting? Its hard to create a % of infestation based on the drop and what my bee population is right now.


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## Arnie (Jan 30, 2014)

beenoob, I think you're good to go.
Don't forget to do the one time treatment in December when there is no brood. That's the really important one.


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## rangerpeterj (Dec 27, 2015)

Arnie I'm in Franktown Co south of you .When in Dec do you treat.I use OAV with a homemade pipe.I treated in Aug a series 3, 7 days apart. I had a good mite drop ,but on retesting with alcohol shake,still had 7% so I did another treatment of 3,7 days apart.Had huge mite drop before leaving the month of Oct.I was going to call it good until Dec treatment.


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## Arnie (Jan 30, 2014)

Ranger,
After supers come off I always do 4 treatments a week apart. Usually clears it right up. Sometimes a fifth is needed, but not very often.

The December treatment is around the first week of December. This year is so warm I am going to check to make sure to get some cold weather before the treatment. We should have some cold by then.


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## johno (Dec 4, 2011)

My feeling about OAV treatments is that about 2 weeks after your final treatment you should do a count with a half a cup of bees. If you are above 6 mites start all over again. I would continue treatment until mites are at an acceptable level. You could change your treatment to Apivar but here again you are going to a treatment that some claim is already showing signs of mite resistance Or you could try FA which is also an organic acid, but harder on bees as it is an actual vapor being breathed by the bees and also does not have constant results due to temperature. Thymol based treatments have also been found to be temperature dependent so we do not have much choice in treatments, but OAV has shown to be the mildest treatment available and not to forget the price is right.
Johno


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