# Is it tougher and tougher to control mites with OAV?



## e-spice (Sep 21, 2013)

Background
I've had bees for six years now. My hive count has steady increased to 12 production hives and about 12 nucs. Production hives looked great during the flow and produced 120 pounds of honey per hive.

Treatment method
I treat with OAV only with a ProVap 110, solid bottom boards and seal the entrance with a cloth for 10 minutes. I use 1 gram of OAV per brood chamber. I always treat during the winter broodless period.

I did 3 OAV treatments at 7 day intervals in July as I always do. One month ago all hives looked great. Solid brood patterns and lots of bees. I didn't do an alcohol count before starting but began treating with OAV again two weeks ago, about the same time I do each year. I'm in the middle of 5 OAV treatments, 5 days apart. I've inspected the hives over the treatment period and have been alarmed at the loss of population, suddenly horrible spotty brood, and more and more deformed wings. I did an alcohol count yesterday of a hive after three OAV treatments. Mite counts are still at 30 per 300 bees. I'm starting to think some of my production hives are a lost cause at this point. After my 4th OAV treatment last night, I installed a screened bottom board on a hive and got about a 400 mite fall overnight for one hive. Very discouraging. I'll keep hammering them with OAV though.

For whatever reason it seems to me that OAV is tougher and tougher every year to control mites. I know the Europeans say no resistance developed over 30+ years. What's everyone else's thoughts on this?


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## Oldtimer (Jul 4, 2010)

No issues where i am. However for me anyway, i found from the gitgo, that treatments 5 or 7 days apart were ineffective, to get a good result I had to do 7 treatments 3 days apart.


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## e-spice (Sep 21, 2013)

Oldtimer said:


> No issues where i am. However for me anyway, i found from the gitgo, that treatments 5 or 7 days apart were ineffective, to get a good result I had to do 7 treatments 3 days apart.


Interesting. Thank you for the reply Oldtimer, sir. Do you use any other treatments or is it OAV exclusively?


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## Oldtimer (Jul 4, 2010)

No i rotate several treatment methods including synthetic strips, formic acid, and thymol. One treatment spring and one treatment fall. Right now the hives have cardboard strips soaked in oxalic acid / glycerine mix.


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## Saltybee (Feb 9, 2012)

Another poster had better luck with a new bottle of OA. It is hydroscopic, any chance you are just dosing with more water?


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## e-spice (Sep 21, 2013)

Saltybee said:


> Another poster had better luck with a new bottle of OA. It is hydroscopic, any chance you are just dosing with more water?


I am using the Florida Labs oxalic acid with the bag sealed up and stored inside. It seems to be working - I had a 400 mite drop overnight.


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## crofter (May 5, 2011)

What kind of mite fall did you see in July? Has anything changed in the numbers of surrounding colonies. A 400 drop tells you the OA is working but also tells you that there is a heavy load under cappings. Either the July treatments left too many survivors or you have had a heavy influx.
In any case I would continue the treatments every 5 days till the drops are close to zero.

I dont subscribe to the philosophy of mercy for survivors: take no prisoners!  Actually, being quite a distance from other kept bees and no ferals I have an easy time keeping mites very near zero. If the numbers start to sneak up on you even a bit, the effort to control them is exponential.

Different weather patterns year to year could make a considerable difference. Like whether or not they are on a brood break from dearth at the summer treatment.


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## e-spice (Sep 21, 2013)

crofter said:


> What kind of mite fall did you see in July? Has anything changed in the numbers of surrounding colonies. A 400 drop tells you the OA is working but also tells you that there is a heavy load under cappings. Either the July treatments left too many survivors or you have had a heavy influx.
> In any case I would continue the treatments every 5 days till the drops are close to zero.
> 
> I dont subscribe to the philosophy of mercy for survivors: take no prisoners!  Actually, being quite a distance from other kept bees and no ferals I have an easy time keeping mites very near zero. If the numbers start to sneak up on you even a bit, the effort to control them is exponential.
> ...


All good points - thank you for the reply. I didn't measure the July drop. One lesson coming out of this is to do better monitoring, not rely on the calendar because, as you said, every year is different. Agreed about continuing the treatments until the count is close to 0. What treatments do you use?


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## little_john (Aug 4, 2014)

e-spice said:


> I know the Europeans say no resistance developed over 30+ years. What's everyone else's thoughts on this?


 VOA only for this European. Until this year, 1x treatment in late December kept Varroa in check. This year I've added a 4x 5-day program (last dose tomorrow), as a 'belt and braces' measure. This may not be strictly necessary, but as it's so cheap and quick to do - why not ? Zero winter losses for the last 8 years or so (haven't actually been counting), so for this apiary Varroa no longer presents as a problem - a nuisance, but not a problem. 
LJ


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## crofter (May 5, 2011)

I used formic acid on pads for several years then switched to OA wand vaporization and last few years band heater external vaporizations. I had 5 or 6 years no winter losses with average 6 to 8 colonies. (until European foulbrood) I have been only putting a sticky board on one or two hives and pull some drone brood to examine. One round of treatments in springtime and have not had to treat till honey off around end of August Then do a round of about 5 treatments every 4 - 5 days without doing any counts aside from examining pulled drone brood.

We do get a brood break from mid Nov. till probably February. Three miles to the closest bees and that only a handful at that. Not an even playing field compared to someone far to the south and surrounded by kept and feral bees. 

You want to follow some of the New Zealand beekeepers and see the uphill battle they have with mites!


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## psm1212 (Feb 9, 2016)

Espice:

I tried the OAV-only route for a couple of years and found it just did not do the job in a climate that has 11 1/2 months of brood a year. For 2 years now, I have been putting in Apivar strips in July or August the minute I get my supers off of my hives. Spring OAV series, Fall OAV if needed after Apivar strips come out (usually not needed) and then a single-shot OAV between Thanksgiving and Christmas in an attempt to catch them with very little brood. 

This is what works for me. I really wanted (still want) to go exclusively OAV. I have the ProVap 110, so I have already made the investment. Apivar strips are expensive, while OAV costs virtually nothing for me now. But it just didn’t get the job done.


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## tbishop (Feb 28, 2012)

I believe you are experiencing a "mite bomb" year. Last year did your area experience heavy swarming. If so, your bees may be robbing those feral hives out and that is why you are having problems with mite levels. This is what I have dealt with here in Indiana over the last 20 years. It has taken me this long to figure out what what was going on. I use Apivar during this time to help control the mite influx.. In late October I will hit with OA.


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## ericweller (Jan 10, 2013)

e-spice. This is exactly why I changed my fall treatment from OAV to a thymol based product. My first year, I had great results with OAV but after that my losses were over 60%. I still do a winter treatment with OAV but my fall treatments are with a more effective product.


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## crofter (May 5, 2011)

Randy Oliver is doing an approved trial of the Oxalic acid / glycerin solution soaked into cellulose material an placed on brood nest frames. The product is approved and in use in Argentina and I believe in European countries. Correct me if I am wrong on this. Oxalic adid vaporization is virtually a flash treatment with effectiveness for only a few days and only on phoretic mites whereas the OA/glycerine strips affect hangs around for a month on bees and surroundings so the mites cannot avoid exposure at some point in their cycle.

You will be hearing more about this in the future.


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## psm1212 (Feb 9, 2016)

ericweller said:


> e-spice. This is exactly why I changed my fall treatment from OAV to a thymol based product. My first year, I had great results with OAV but after that my losses were over 60%. I still do a winter treatment with OAV but my fall treatments are with a more effective product.


Eric: I am a little surprised you are not having some issues with thymol treatments in Georgia. I lost a couple of hives with Apiguard while trying to treat in the high 80s and have not gone back to it. Have you had any trouble with heat and thymol?


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## psm1212 (Feb 9, 2016)

crofter said:


> Randy Oliver is doing an approved trial of the Oxalic acid / glycerin solution soaked into cellulose material an placed on brood nest frames. The product is approved and in use in Argentina and I believe in European countries. Correct me if I am wrong on this. Oxalic adid vaporization is virtually a flash treatment with effectiveness for only a few days and only on phoretic mites whereas the OA/glycerine strips affect hangs around for a month on bees and surroundings so the mites cannot avoid exposure at some point in their cycle.
> 
> You will be hearing more about this in the future.


Frank:

You are correct about Randy’s work with extended-release OA treatments in hives. UGA and Auburn University have done some studies with Randy’s formula in the Southeast. Randy is in arid Northern California. Auburn University and the University of Georgia are in the humid southeast. I have not seen anything published yet, but I have talked to some folks about the study and it did not go well.


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## squarepeg (Jul 9, 2010)

i can't speak from experience, but i can't help but come to the conclusion after following threads like this one and comparing this discussion to what i remember reading 10 years when i first joined beesource, that mites are indeed getting harder to control as time goes on...

i.e. it sounds like more treatments and varying kinds of treatments are becoming increasingly necessary to keep mite levels down now compared to 10 years ago.

for those of you who have been around for awhile and have been treating for mites is this a fair statement?


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## Kamon A. Reynolds (Apr 15, 2012)

I agree with Old timer. OAV does not kill effectively for more than a few days. We also know it does not kill 100% of exposed mites during the prime effective time of the treatment. Another thing to consider is that OAV (like most treatments) is not great once the mite levels have spiralled out of control. Even if it is killing alot of mites it is missing some and the higher the mite load the more it misses. Alcohol washes are invaluable in my opinion.


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## little_john (Aug 4, 2014)

squarepeg said:


> i can't speak from experience, but i can't help but come to the conclusion after following threads like this one and comparing this discussion to what i remember reading 10 years when i first joined beesource, that mites are indeed getting harder to control as time goes on...
> 
> i.e. it sounds like more treatments and varying kinds of treatments are becoming increasingly necessary to keep mite levels down now compared to 10 years ago.
> 
> for those of you who have been around for awhile and have been treating for mites is this a fair statement?


My guess is that it's the old chestnut of Local Conditions. For someone who experiences all-year-round brood I can see huge problems there - likewise those who live in a high-density beekeeping area, or where significant numbers of ferals exist. I'm like Frank - located in a fairly isolated area, and in my case one in which I'd bet my pension there are zero ferals within range.

So - my money would be on three things: firstly, that re-infestation is a major factor; secondly, that the mode and technique of applying OA needs to be efficient; and lastly, the increased number of people now using OA - and perhaps expecting it to be a simplistic 'magic bullet' - could explain the higher number of 'reported failures', and so rather than mite resistance being the cause, it's simply a function of higher numbers of users, many of whom will not yet have had extensive experience in it's use.

I'm fairly sure that if I only possessed a varrox-style vapouriser, then I could return to just the one winter application, and continue to 'get away with it' - but the current band-heater designs (I apply via an existing feed-hole) are so convenient to use that multi-dosing now presents as being a time-effective methodology.
LJ


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## crofter (May 5, 2011)

,Snip> and lastly, the increased number of people now using OA - and perhaps expecting it to be a simplistic 'magic bullet' - could explain the higher number of 'reported failures', and so rather than mite resistance being the cause, it's simply a function of higher numbers of users, many of whom will not yet have had extensive experience in it's use.<Snip>


little_john said:


> This, and the intensity and cross country transportation of pollinating bees may have increased. A lot of these colonies get broken down and become the nucs shipped all over to start new colonies and replace deadouts. There seems to be more acceptance that deadouts were caused by mites and not excused as starved, froze to death, absconded or poisoned.
> 
> I think these factors are enough to explain the perception that the mites may be getting harder to deal with.


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## Mike Gillmore (Feb 25, 2006)

squarepeg said:


> i.e. it sounds like more treatments and varying kinds of treatments are becoming increasingly necessary to keep mite levels down now compared to 10 years ago.


Ten years ago most beekeepers were using the "other" standard products to combat mites. Today, OAV has become the prime method and everything else is being compared to OAV. 

I think you are seeing more discussions like this because OAV was never really intended to "replace" the others, it is just another weapon in the arsenal. We are beginning to see the pendulum swing back the other direction as it is becoming more clear that it is not the lone silver bullet everyone was hoping it would be. Too many variables with climate for it to be a one size fits all treatment.


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## johno (Dec 4, 2011)

In my humble opinion, the more you treat with OAV the safer you are, I see no detrimental effects on bees so I think you could treat every 3 days for 6 months and if that does not wipe out your mites you are importing them faster than you can kill them.


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## Saltybee (Feb 9, 2012)

It would not be unusual for a species to respond to increased mortality with increased fertility. The difference between EUs 30 years experience and that reported here maybe in methods. Supers comes to mind.


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## psm1212 (Feb 9, 2016)

I have a 2009 edition of Keith Delaplane's _First Lessons in Beekeeping_. The 24 hour sticky board natural drop treatment threshold for the Southeastern US is as high as 190 mites. Can you imagine seeing 180 mites on your sticky board every 24 hours and thinking, "Well, not a problem because it doesn't exceed the threshold."? 

In the relative short time I have been beekeeping, I have seen the alcohol wash threshold move from 10%, to 5%, to 3% and now some are saying 1%.

My non-scientific, finger-to-the-wind assessment is that not a lot has changed with the varroa mite, but the virulence of the viruses they vector has radically shifted. What was survivable with high mite loads only 15 years ago, is no longer survivable today. 

I believe (again, no science here -- spitballs only) that what we are actually seeing is increased and intensified viral loads, not increased mite loads.

I continue to believe that the VSH, Hygenic, biting mite breeding programs are not the solution.  If we are going to breed for a better bee, we need to breed the bee that can withstand these viral loads. Weaponizing them to kill/attack/harass mites is just a losing battle. 

Just an uneducated, unscientific opinion. I have about as many of them as I have mites.


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## ericweller (Jan 10, 2013)

psm1212 said:


> Eric: I am a little surprised you are not having some issues with thymol treatments in Georgia. I lost a couple of hives with Apiguard while trying to treat in the high 80s and have not gone back to it. Have you had any trouble with heat and thymol?


I have had good results with thymol. The only issue I have had was that it chases the bees out of the hive for a few days. I use ApiLife Var and give 3 treatments, 7 days apart.


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## psm1212 (Feb 9, 2016)

ericweller said:


> I have had good results with thymol. The only issue I have had was that it chases the bees out of the hive for a few days. I use ApiLife Var and give 3 treatments, 7 days apart.
> View attachment 51209


I have only used Apiguard. I really liked thymol, but I gassed out a couple hives and stopped using it. I may give ApiLife Var a try. Maybe it is a little milder and more suited for our impossible heat. Thanks Eric.


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## Juhani Lunden (Oct 3, 2013)

psm1212 said:


> I continue to believe that the VSH, Hygenic, biting mite breeding programs are not the solution. If we are going to breed for a better bee, we need to breed the bee that can withstand these viral loads. Weaponizing them to kill/attack/harass mites is just a losing battle.


I agree.
I have been eagerly waiting for the day, and asking, when do the VSH projects in Europe start their TF experiment. Because breeding a 100% VSH bee is useless, unless it is tested in real life circumstances, where outside mite flow will cause the mite and virus load go skyrocketing no matter how resistant your bees are. 

Bond method is needed in the end, no matter how you do the breeding. 

There are huge differences in virus resistance. It is essential to combine virus resistance in the breeding of varroa resistance. This is why I always have criticized the use of low thresholds in IPM methods. Randy Oliver is using 3%, 5 % would have been selecting harder for virus resistance.


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## NDnewbeek (Jul 4, 2008)

How much does everyone know about antibiotic resistant bacteria and how they become resistant to antibiotics over time? The same thing likely happens when treating mites. It is microevolution. In any populations of mites in a hive, there will likely be a few whose genetic makeup permits them to survive/tolerate the treatment (think one end of a bell curve). They survive the treatment - live to reproduce and pass that genetic resistance to their offspring that then also carry resistance to the treatment. This necessitates higher dosages and stronger treatments. A few have the resistance to that higher dosage, survive, reproduce, and so on.

That is the process by which we have produced antibiotic resistant bacteria. It is also why plague doesn't decimate human populations as it did in the past (most of us carry the resistance to survive it passed on to us by the few ancestors who survived the first outbreaks). Each time you treat - if you don't kill all the mites in the hive - the survivors reproduce and you get subsequent generations of mites that are ever harder to kill with that treatment. Most pest companies and pesticide producers understand this and it is why they rotate their treatments and treatment formulas regularly.


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## johno (Dec 4, 2011)

Hey Nd OAV is like a swatter is to flies, you physically hurt them little mites.


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## JWPalmer (May 1, 2017)

I have a hard time imagining a world were the varroa mite developes a resistance to having its feet disolved off and bleeding to death (my understanding of OA's mode of action).


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## karenarnett (Mar 25, 2012)

This has been a very helpful thread! Next year I will try caging the queen in late summer for a broodless period. On the bright side, I've seen virtually no SHB this year!


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## e-spice (Sep 21, 2013)

JWPalmer said:


> I have a hard time imagining a world were the varroa mite develops a resistance to having its feet dissolved off and bleeding to death (my understanding of OA's mode of action).


In the middle of a mite crisis, the visual of a mite getting its feet dissolved is giving me some degree of satisfaction.


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## msl (Sep 6, 2016)

My "finger to the wind spitball take" is the viruses have been getting worse as shown by the lowering of treatment thresholds and the off label, off season use of OAV has been growing. These 2 combined mean people are treating earlier and earlier at a time when its not effective, so they have more weeks before broodless so they need more treatments. 



> Hey Nd OAV is like a swatter is to flies, you physically hurt them little mites.


sure, but kill a large amount of a population and you then have the fastest and most warie flys left to breed.. further more its mode of action hasn't been proven so making any claim is a bit silly. a change in the mites phoirc period by a day or so could bugger OAV schedules 



> Each time you treat - if you don't kill all the mites in the hive - the survivors reproduce and you get subsequent generations of mites that are ever harder to kill with that treatment. Most pest companies and pesticide producers understand this and it is why they rotate their treatments and treatment formulas regularly.


yes and no, I am all for rotations, you need to kill off what one mode of action didn't 
But we need to look at what happend with mites in the past. 


> "Pyrethroid resistant mites were first detected
> in the Lombarby region in the north-west of
> Italy around 1991. This region was closely
> connected by a well-established movement of
> ...





> n 1997 pyrethroid resistant mites were
> detected in the USA. Although the first
> reports of resistance were from South
> Dakota,1
> ...


 Martin 2015

It doesn't seem to be a slow march towards resistance on a landscape scale , more it seems to be a mutation of a single mite that then reproduces and spreads by bee movement. The problem isn't you might develop resistance in your yard, its that some one some were might, and if the bulk of hives arn't having there treatments rotated, this mutation will quickly become the dominant type. The view is reinforced by the fact that the mutation that gave Pyrethroid resistant mites is different in the US, UK, and mainland Europe. González-Cabrera EtAl 2016


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## unstunghero (May 16, 2016)

crofter said:


> Randy Oliver is doing an approved trial of the Oxalic acid / glycerin solution soaked into cellulose material an placed on brood nest frames. The product is approved and in use in Argentina and I believe in European countries. Correct me if I am wrong on this. Oxalic adid vaporization is virtually a flash treatment with effectiveness for only a few days and only on phoretic mites whereas the OA/glycerine strips affect hangs around for a month on bees and surroundings so the mites cannot avoid exposure at some point in their cycle.
> 
> You will be hearing more about this in the future.


I have a friend that says OA-glycerin soaked pulp egg carton strips hung over brood frames for 42 days works.


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## little_john (Aug 4, 2014)

NDnewbeek said:


> How much does everyone know about antibiotic resistant bacteria and how they become resistant to antibiotics over time? The same thing likely happens when treating mites.


A totally different scenario entirely. Bacteria are single-cell organisms, and as such, any mutation which occurs stands a pretty good chance of being accepted. 

This is in marked contrast to a mutation in a higher organism which impinges upon the millions of differentiated cells which form highly complex systems - the full acceptance of which is essential if such a mutation is to result in a fully viable organism. So - bacteria mutate very easily (and also very quickly) whereas mutations in higher organisms are extremely rare and only occur over an extended timescale.
LJ


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## little_john (Aug 4, 2014)

NDnewbeek said:


> That is the process by which we have produced antibiotic resistant bacteria. It is also why plague doesn't decimate human populations as it did in the past (most of us carry the resistance to survive it passed on to us by the few ancestors who survived the first outbreaks).


What RUBBISH. We do NOT possess resistance to the plague bacterium. The reason why plague is under control these days is as a result of improved Public Health measures and improved personal hygiene. Suggest you read: https://en.wikipedia.org/wiki/Bubonic_plague

Studies have been done recently which indicate that it is highly unlikely that the black rat (_rattus rattus_) was the vector for the Black Death (bubonic plague) which swept through Europe in the Middle Ages: it is far more likely that the disease spread - by means of flea bites - from person to person. Apparently, transmission via the rat could not account for the speed of spread.

These days people in First World countries wash fairly regularly. In those days they didn't, and so fleas on humans were able to spread the disease.
LJ


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## Saltybee (Feb 9, 2012)

No matter the method of control, including TF, leaving any alive, and there are some left alive even if it is from your neighbors, creates a population vacuum. The most successful mite strategy in a vacuum is rapid reproduction.

Mites may not be able to develop resistance, that does not prohibit adaptation to treatment.


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## Eaglerock (Jul 8, 2008)

In all my years of beekeeping, I haven't had much of a problem with mites. Confectionery Sugar kills the mites and the bees use the sugar. It's a win win. 
My stores sell Formic Pro which is safer than the other ones on the market. We sell other brands but this is safer and natural.


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## little_john (Aug 4, 2014)

Saltybee said:


> Mites may not be able to develop resistance, that does not prohibit *adaptation to treatment*.


But is it really a case of "adaptation to treatment" ? 

Prior to Varroa arriving, there was no treatment for Varroa (obviously), but there was - from the Varroa's point-of-view - a total absence of any other organism occupying that particular parasitic niche. So, for the mites it was a case of all their birthdays having been rolled into one - with no competition, and no effective resistance against their activities.

All a treatment (such as VOA) is doing is trying to 'wind the clock back' to the days before Varroa - admittedly, such that the same parasitic vacuum continues to exist - but your wording unfortunately gives the impression that treatment is an active participant in stimulating the mite to breed. Whereas VOA is benign as a stimulant - it is the mite's reproduction which remains unopposed and thus it will continue to breed at the same rate as it did before. There's no evidence that this reproduction rate has changed, and thus no evidence that adaptation has taken place.
LJ


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## username00101 (Apr 17, 2019)

I also wonder about mites ability to develop resistance to oxalic acid with glycerin, as the mode of delivery is different than OA Vaporization. 

Glycerin release, is, I'm assuming a vapor over time? 

While OAV are small solid crystals.


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## 2Sox (Dec 17, 2011)

Eaglerock said:


> In all my years of beekeeping, I haven't had much of a problem with mites. Confectionery Sugar kills the mites and the bees use the sugar. It's a win win.
> My stores sell Formic Pro which is safer than the other ones on the market. We sell other brands but this is safer and natural.


I rotate treatment: OAV in the spring and Formic Pro in the Fall - one month apart starting around Labor Day. First time ever I had 100% coming out of winter. (6/6). Always wrap my hives but used Bee Cozys for the first time last winter and I'm sure it helped.

This may bring up some debate, but I never do mite counts and never will. I can't see the logic in spending the time testing for something that is always going to be here. (Yes, I know the argument about breeding stronger bees. That's a discussion for another time.) Tracheal mites in my area are a VERY big problem. It breaks my heart to see hundreds of bees in the Spring, crawling on the ground unable to fly (Much of my yard is concrete) so even if I had low varroa counts, I'd be treating anyway. A couple of OAV treatments in spring and hardly any bees crawling around. (The wands take much too long and I just bought a fogger.)

Then I hit them in the fall with Formic Pro, as I mentioned. Seems to take care of things.


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## GregB (Dec 26, 2017)

little_john said:


> But is it really a case of "adaptation to treatment" ? ............LJ


Somehow, the "adaption to treatment" by default is viewed as if some qualitative change - like say, a thicker shell.

Well, the behavioral changes are one such thing that could develop rather quickly.
Fortunately for them, the animals are not plants and can actually move around and scratch and more...

For example, IF you are regular sauna user (I am) you know really well about different temperature gradients in the sauna and select the zone which fits you the best.

I will challenge the OA applicators now - do you know about and do you have absolute control at all times of the OA concentrations in every single hive (AND in every single corner of that hive) while it is being treated?

One thing the mites should do (and they will, being the darn robust creatures they are) - figure out where in the hive they can temporarily hide out to improve their chances.
There is plenty of behavioral mite training going on just for this single parameter...

It maybe the mites who like it cooler (OR warmer OR more humid OR more dry OR at the back of the hive) are being selected as we speak by the pretty random OA applications across the variety of the hives and the beekeepers and the locations. Gee, artificial selection of the mites for the best survivors is going with some crazy pace...


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## crofter (May 5, 2011)

username00101 said:


> I also wonder about mites ability to develop resistance to oxalic acid with glycerin, as the mode of delivery is different than OA Vaporization.
> 
> Glycerin release, is, I'm assuming a vapor over time?
> 
> While OAV are small solid crystals.


There are over one hundred pages of posts on NZ beekeeping forum discussing OA/ gly. The assumption seems to be that the glycerine provides a moist rather sticky mixture with the oxalic acid that is spread around by the bees bodies over the course of about a month as they chew up and discard the strips. 

Sublimed OA may not remain in crystal form for very long in the hive. They pick up moisture quite quickly and dissipate. Moving around on either comb or bees will expose the mites delicate feet to the effects of the acid and how it is presented may not make a lot of difference in regard to the possible development of resistance. The oa/gly gives a timed release affect.


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## Saltybee (Feb 9, 2012)

But is it really a case of "adaptation to treatment" ? LJ keeping me in check with quick sloppy language.

Really can't say that it has happened. Am saying it will happen. Reproduction rate of the mite when they arrived was not uniform (assumption on my part) and was developed to suit a host that had defenses. Removal of most mites creates a void that will be filled by those that can fill the void fastest. 

The main point was lack of resistance to OA true or false is not the complete story of whether it is harder to keep them in check.


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## Gray Goose (Sep 4, 2018)

Oldtimer said:


> No i rotate several treatment methods including synthetic strips, formic acid, and thymol. One treatment spring and one treatment fall. Right now the hives have cardboard strips soaked in oxalic acid / glycerine mix.


How long do you leave the cardboard strips in Oldtimer? Have you tried the blue Towels? what is it about the cardboard you like?

thanks In advance
GG


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## msl (Sep 6, 2016)

> We do NOT possess resistance to the plague bacterium. The reason why plague is under control these days is as a result of improved Public Health measures and improved personal hygiene.


yes, and no 
The CCR5-Ä32 mutation is from plague survivors, pre plage is was 1 in 20,000, to day its one in 10 of the European pop and confers HIV resistance.
but for most humans, the change was IPM (attacking the vectors), its still out there, we see out breaks in prairy dogs in my area. how ever if the IPM measures had not been enacted we likely would see higher levels of CCR5-Ä32 in the gen pop. 



> But is it really a case of "adaptation to treatment"


behavioral resistance is still resistance.. genetically bait/trap shy mice/rats are out there. In areas that have a large amout of people treating brood on with corces of OAV a reduction in the mite phoric period would be a likely adaption of behavior as your slecting for the mites that go back into brood between treatment , So thats a +1 for extended action treatment like dribble and OAG. There are people (anti treatment) arguing that the study's show this has all ready happened and the poric period of mites has shortened, but its hard to compare the data for the 90s to now, and realy its amazing how little we know about these buggers, 2 years ago we all new they feed on bee blood... yet some how no one had bothered to test that?


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## little_john (Aug 4, 2014)

Evidence of historical antibody production from hundreds of years ago, is not the same as historical adaptations continuing to offer modern-day protection to the same disease - if it did then there would no longer be any need for immunisation programs for our young, nor for the frequent top-ups of Anthrax jabs.



> > But is it really a case of "adaptation to treatment"
> 
> 
> behavioral resistance is still resistance..


Developed resistance to a systemic miticide may be a reasonable observation - but to then claim that such treatments have actually improved the biological performance of the mite in some way is baseless.

I would suggest that there are two factors which could account for this perception: firstly, as we learn a little more (but still nowhere near enough, certainly) about the Varroa mite, then our expectations become greater - in essence the bar becomes gradually raised such that we now expect total, or near total eradication from whatever treatment is being used. We compare treatments: we monitor the mite fall; we have developed methods of determining levels of infestation; resistance to some systemic miticides have indeed occurred - none of these existed 20-30 years ago, and so as a result there is a perception that the problem is actually worsening.

Secondly - and perhaps more importantly - I would suggest that there is a higher concentration of honeybee colonies per given area of land mass in the United States than anywhere else on earth. The spread of parasites and disease are well-known to go hand-in-glove with population density, and so the Varroa problem has become more severe in the States than elsewhere, and especially wherever the colony density is highest. Now whether this is factually true or not I couldn't say, but it would account for a perception of increased severity, especially when contrasted with reports from those who have the Varroa mite problem well under control.
LJ


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## jim lyon (Feb 19, 2006)

Oldtimer said:


> No issues where i am. However for me anyway, i found from the gitgo, that treatments 5 or 7 days apart were ineffective, to get a good result I had to do 7 treatments 3 days apart.


Interesting, thanks for this. Oh, and love your tag line. Good ole Sol. Almost forgot about him.


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## little_john (Aug 4, 2014)

msl said:


> The CCR5-Ä32 mutation is from plague survivors, pre plage is was 1 in 20,000, to day its one in 10 of the European pop and confers HIV resistance.


I've always found this claim of a connection to be somewhat 'fishy', as HIV is caused by a virus, and plague by a bacterium - which suggests to me that any transferred resistance must be as a result of lucky happenstance - i.e. pure coincidence.

So I 'did a Google' which came up with the following update re: this idea:



> La Jolla, CA, February 11, 2004 -- A group of scientists at The Scripps Research Institute have provided strong evidence that a popular hypothesis concerning the origins of a genetic mutation common among Caucasians of Northern European descent that protects against human immunodeficiency virus (HIV) is wrong.
> 
> The hypothesis suggests that the mutation conferred resistance against bubonic plague in the Middle Ages, much as it does against HIV today. This idea was based on the fact that the mutation first appeared around the same time that the "Black Death" plague epidemic killed a third of Europe's population in the years 1346–1352. Since HIV was not present in Europe at this time, individuals with the mutation must have been protected against some other disease.
> 
> ...


Dunno whether there's anything more recent on this particular topic.
'best,
LJ


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## gww (Feb 14, 2015)

LJ


> I would suggest that there are two factors which could account for this perception: firstly, as we learn a little more (but still nowhere near enough, certainly) about the Varroa mite, then our expectations become greater - in essence the bar becomes gradually raised such that we now expect total, or near total eradication from whatever treatment is being used. We compare treatments: we monitor the mite fall; we have developed methods of determining levels of infestation; resistance to some systemic miticides have indeed occurred - none of these existed 20-30 years ago, and so as a result there is a perception that the problem is actually worsening.


I am the dumbest guy to comment on this thread and so what I say has no meaning from me but is just an observation. I saw a randy oliver vidio I think in Europe or NZ. I can not even remember the treatment they were talking about but do remember it pertained to a 97 percent kill rate of mites. Randy put out the position that a high kill rate would speed the rate of resistance to the treatment compared to something with a smaller percentage of kill rate.
Cheers
gww


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## e-spice (Sep 21, 2013)

tbishop said:


> I believe you are experiencing a "mite bomb" year. Last year did your area experience heavy swarming. If so, your bees may be robbing those feral hives out and that is why you are having problems with mite levels. This is what I have dealt with here in Indiana over the last 20 years. It has taken me this long to figure out what what was going on. I use Apivar during this time to help control the mite influx.. In late October I will hit with OA.


Sorry for the delayed reply tbishop - that's an interesting thought. I did have a lot of swarms this year, as in, nearly all my stronger hives and nucs. You may very well be right in that the swarms are getting robbed out and introducing additional mites.


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## e-spice (Sep 21, 2013)

ericweller said:


> e-spice. This is exactly why I changed my fall treatment from OAV to a thymol based product. My first year, I had great results with OAV but after that my losses were over 60%. I still do a winter treatment with OAV but my fall treatments are with a more effective product.


I'm leaning toward trying that eric. Are you referring to Apiguard?


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## msl (Sep 6, 2016)

> Randy put out the position that a high kill rate would speed the rate of resistance to the treatment compared to something with a smaller percentage of kill rate.


I think it was NZ



> I will challenge the OA applicators now - do you know about and do you have absolute control at all times of the OA concentrations in every single hive (AND in every single corner of that hive) while it is being treated?


with dribble, yes. 
Rademacher EtAl 2017


> In order to reach high efficacy, the ingredient acting by contact must be distributed in the colony.
> The distribution of OAD was shown by macroCT. The results of the roentgenoscopy showed high
> density values for the individual bees in the test, much higher than in the control measurement. A good
> distribution was already achieved after 10 min; this could be documented in the central and boundary
> ...


More importantly then all over the hive, its spread to every bee.


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## little_john (Aug 4, 2014)

gww said:


> LJ
> I saw a randy oliver vidio I think in Europe or NZ. I can not even remember the treatment they were talking about but do remember it pertained to a 97 percent kill rate of mites. Randy put out the position that a high kill rate would speed the rate of resistance to the treatment compared to something with a smaller percentage of kill rate.
> Cheers
> gww


Hiya
That assumes that the survivors 'actually survived the treatment', as opposed to simply not being killed during the process of treatment. The best example of this being mites protected by having been located within a capped brood cell during VOA treatment. They are not killed by the treatment, but are no more likely to have developed a resistance to it than those which died. Yet they are - in a sense - survivors.

In the same way, small numbers of colonies of AMM 'survived' the ravages of the tracheal mite within the British Isles during the 1920's, when most colonies were wiped-out. But did they survive those mites by virtue of having a genetic difference, or did they simply not come into contact with sufficient numbers of mites ? I think it's significant that those colonies which survived were located at the 'extremities' of the island group (relative to the initial outbreak), such as in Western Ireland and Northern Scotland. Yet AMM enthusiasts claim that these colonies are 'survivor stock'. In one sense, they are - but in another sense they're not. 

Same with Randy's 3% of 'survivors' - if they actually survived the treatment, then yes - the numbers of genetic mutants (or whatever caused their survival) will quickly become concentrated - but if they've somehow simply avoided being killed, then nothing will have changed. 

LJ


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## Gray Goose (Sep 4, 2018)

msl said:


> I think it was NZ
> 
> 
> with dribble, yes.
> ...


re: this statement: I will challenge the OA applicators now - do you know about and do you have absolute control at all times of the OA concentrations in every single hive (AND in every single corner of that hive) while it is being treated?

YES i know about and at all times , on every single hive
I am going for the "assist" i know i do not kill all and am ok with that. (ie small kill rate)


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## GregB (Dec 26, 2017)

> I will challenge the OA applicators now - do you know about and do you have absolute control at all times of the OA concentrations in every single hive (AND in every single corner of that hive) while it is being treated?


And does it happen EVERYWHERE and at EVERY single application FOREVER and EVER for years and years to come (the 100% mite kill efficiency, to clarify)?

I can not believe someone will seriously and honestly say - YES.

Because the YES means - we should not be having the mites in the years 2019/2020 anymore everywhere.
Basically of this immediate writing.

The mites should be ALL killed and done with and forgotten about and there is nothing to talk about.
We have 100% effective formulations and methods of applications of those organic and natural acids (OA and FA) available.

I don't get what is the problem still on hand and why is the talk?
What? We still have mites?


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## Saltybee (Feb 9, 2012)

" Even after 14 days, the density of the bees was still significantly higher than prior to treatment, indicating
a potential efficacy of at least up to 14 days."

Is this "on" the bees rather than "of" ?

Does not match the real world; Not seeing anyone saying I treat the 1st time on day one and again on day 14 with great results.


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## Gray Goose (Sep 4, 2018)

GregV said:


> And does it happen EVERYWHERE and at EVERY single application FOREVER and EVER for years and years to come (the 100% mite kill efficiency, to clarify)?
> 
> I can not believe someone will seriously and honestly say - YES.
> 
> ...


Greg, I read the question "do I know the concentrations of OA, in all places." YES I Do. on the lid 0%, on the Floor 0, in the corners 0, in the spot I placed the GlyOA pad 25g in every Hive same pad ,same amount. I know how much is where. So hence my answer. Nothing about kill % in the question I answered. And I do not care, the way I do it it is a little help, the bees need to do the rest.
GG


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## msl (Sep 6, 2016)

> Does not match the real world; Not seeing anyone saying I treat the 1st time on day one and again on day 14 with great results.


I would counter most of those talking are (fad) OAV users, dribble is much different, kills mites much longer, kills many more mites in a brood on situation because of this. 
And that bring a good point to mind, the old Tx schedules were based on dribble, and the climbing number of Tx with OAV may be do to its limited effectiveness with brood on ,it does gain a few points broodless and kills more mites, but its short action period (2 or so days) limits it efectness when there are mites emerging daily 

here is me from a year ago



msl said:


> OAV kills more mites in a brood less situation, but OA trickle drops mites for a longer peirod of time... ie mite peak drop is usaly 6 or so days. Studys are showing that when used brood on it kills more mites, it seems the longer action time alows it to contact more mites as they emerge and thus kill more mites even thow it kills a lower prestantage of mites exposed to it
> 
> _Significantly more mites fell six days after OA application than 2 or 4 days after OA application. This statistic may be interpreted several ways. One interpretation is that OA has residual activity against varroa for at least six days post-treatment. Charrière et al. (2004) and Gregorc and Planinc (2004) report that mite fall can occur over a 3 week period in hives treated with OA _ Aliano 2008 refereeing trickle https://digitalcommons.unl.edu/cgi/...redir=1&article=1181&context=entomologyfacpub
> 
> ...





> Studys show OAV kills more mites in a brood less situation, but OA trickle drops mites for a longer peirod of time... ie mite peak drop is usaly 6 or so days. Studys are showing that when used brood on it kills more mites, it seems the longer action time alows it to contact more mites as they emerge and thus kill more mites even thow it kills a lower prestantage of mites exposed to it
> 
> "Significantly more mites fell six days after OA application than 2 or 4 days after OA application. This statistic may be interpreted several ways. One interpretation is that OA has residual activity against varroa for at least six days post-treatment. Charrière et al. (2004) and Gregorc and Planinc (2004) report that mite fall can occur over a 3 week period in hives treated with OA Aliano 2008 refereeing trickle https://digitalcommons.unl.edu/cgi/v...tomologyfacpub"
> 
> ...


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## Juhani Lunden (Oct 3, 2013)

I eagerly wait how long we have to wait for the first attack against OAD, by the OAV users...


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## little_john (Aug 4, 2014)

I've never once used the Dribble Method, nor have I ever been tempted to use it - not because of what others say or claim - positive or negative - but for 3 reasons. 
Firstly, the presence of sugar syrup will undoubtedly cause the bees to ingest some of the solution. I also question why sugar is needed as a carrier. 
Secondly, I question the uniformity of spread - with those at the top of the seam getting wet, whilst those at the bottom will stay dry. There is therefore a reliance upon bee to bee spreading of OA, which may not be that effective, especially during winter.
Thirdly, and most importantly, for maximum effect OAD requires a hive to be fully exposed during winter, and wetting the bees during a very cold time of the year.

It's also more labour intensive than VOA, but that isn't a factor in my own decision-making.

Spraying OA solution would undoubtedly provide more guaranteed coverage, but would involve more disruption and exposure at a time when the bees benefit most from being left in peace.
LJ

PS - this isn't 'an attack' against OAD - it's just never appealed to me as a treatment, when contrasted with VOA.


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## crofter (May 5, 2011)

Below is an example of how results can be misleading. Not deliberately so, but there can often be incidental effects that could be seen to discount the basic premise. Note in the highlighted words the time frame of the OA vaporizations which are much further apart than presently considered most effective. 

For what little that is worth I think the applications with glycerine as the carrier will be seen to have a timed release benefit. Also, as compared to sugar syrup, glycerine appears unpalatable to bees so less likely to be ingested. The instant, and no hive opening benefits of the vaporising method can be used to advantage but the shortfalls of it should be well recognized.


_"The glycerin dribble caused by far the greatest initial increase in mite drop--the other three were about the same. The two dribbles resulted in the best mite reduction initially, but by Day 26, all four colonies exhibited roughly 50% reductions in their alcohol wash counts from baseline--after a single dribble, compared to three vaporizations at roughly 10-day intervals. Keep in mind, that there was an n of only one for each treatment, so don't run too far with this data.

The above results suggest that the added humectants increased the efficacy of the OA greatly--initially as well as over time, and indicate that the
effect of the crystals from vaporization is very short term (this is supported by Saskia Schneider's findings)". http://community.lsoft.com/scripts/w...L&D=0&P=115030

it took 3 OAVs to have the same effect as one dribble"_


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## mgolden (Oct 26, 2011)

I find with two OAVs during no brood period in late fall and Apivar in early spring, mites are very minimal. This is consistent with what Ian Steppler is finding. We do have a distinct winter for 5 months. I did a OAV and installed a sticky board for 4 days to check mite infestation in early Sept and counted less than 10 mites per hive.

Vaporization is the only practical way(IMHO) in late fall. Opening a hive and exposing both brood boxes and dribbling a wet syrup is not good. One needs to dribble each brood box to get an effective control. One is also breaking propolis seal.

I use the Varrox on my four hives and time is not a factor. It takes 30 mins tot at each location, as there is two hives at each location. There is little vapor exposure when one is standing 10 ft away, so very safe to use.

If I had more hives, a band heater type vaporizer and vapor mask reduces would be the next logical step as the time is 30 secs per hive.


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## msl (Sep 6, 2016)

LJ... I dissagree on ALL points 

1 when they do that It knocks back Nosema ceranae https://www.sciencedirect.com/science/article/abs/pii/S0034528815300333. Tests with water have failed. seems its a carer and helps with the spread. 

2 post 53, they did a cat scan in 2mm slices to see the spread. Bee to be contact spreads dribble, vap nees the convention currents of the hive and lose cluster.. thats why dribbles appulaction temp is lower then vap

3 not a single study shows this to be an issue.. if its cold enuf for that to be an issue, the cluster is too tight of vap to be effective any way.. 

labor? ... I step out of the truck and get to work. My new tool is a home depto spray bottle... 1.5ml a pump.. split a box, 4 pumps per seam . In a small yard I am back on the road before I could have drug out the batt and got the band heater up to temp, much less waited for it to cool after I was done.


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## little_john (Aug 4, 2014)

Fine - then you use Dribble, and I'll use VOA. Both of us will be using methods which we're happy with, and so there's nothing left to argue about. I'm NOT advocating that others don't use Dribble - that's up to them - I've just given my reasons why I've never once seriously considered using that method. I don't really care much about what 'studies show': I used to be a scientist and am well-aware of the scientific games which are played. Once my Crown Boards (Inner Covers) have been replaced after the last inspection of the season, they NEVER come off again until Spring. The bees want them sealed-up, and so they stay sealed.

These days I have zero over-wintering losses (plenty of mating failures during the season - but that's a whole different can of worms), and so I'm using this success rate as a barometer by which to judge mite levels, as I've never done a mite count in my life and I'm not going to start now. The day I lose a single colony over the winter period is the day I'll re-assess how I go about tackling the mite problem. "If it ain't broke, then don't fix it." 

This thread is entitled, "Is it tougher and tougher ... etc.", to which my answer is "For me, no - quite the opposite."
'best
LJ


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## msl (Sep 6, 2016)

> I've just given my reasons why I've never once seriously considered using that method.


Green eggs and ham Sam I am. 


> Fine - then you use Dribble, and I'll use VOA


 I use bolth, I build haunted houses so this is the busy time for me, no way could I make 4 trips to all my yards to vape them .Not trying to change your winter ways, just was pointing out that dribble might be a better choice for your "belt and braces"



> This thread is entitled, "Is it tougher and tougher ... etc.", to which my answer is "For me, no - quite the opposite."





little_john said:


> VOA only for this European. Until this year, 1x treatment in late December kept Varroa in check. This year I've added a 4x 5-day program (last dose tomorrow), as a 'belt and braces' measure..
> LJ


I find it odd then that you are now using 400% more treatments, after 8 years of zero winter losses.... Most would take that as things getting harder 
For most of us a single bloodless treatment isn't going to be enuff to get to zero winter loss as you did


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## aran (May 20, 2015)

i have had the best success rotating between OAV, Formic pro and apivar.
This time of the year my MP style nucs which im not taking honey from all have apivar strips on and the production colonies all have formic pro on.
The second round of formic pro will go on in a week or so then nothing until early November/late october when i will use OAV. They will get OAV again in december x 1 round.
I wanted to put apivar on everyone but there is still a lot of honey on the production colonies that i was unable to extract just due to a family crisis going on at the moment.


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## little_john (Aug 4, 2014)

msl said:


> I find it odd then that you are now using 400% more treatments, after 8 years of zero winter losses.... Most would take that as things getting harder


Sure - but they'd be drawing the wrong conclusions. I'm now *choosing* to increase the number of treatments - primarily because it's so easy to do with the latest kit. I don't really *need* to - it's purely that I *want* to - in the interests of keeping healthy bees. 

Zero winter losses simply means that they all 'survived' - what I'm trying to achieve now is to ensure that they enter winter with a seriously reduced mite load and so endure the winter period comfortably, and then emerge in Spring as strong as possible - something rather more than 'just survival'.

It's not that the situation has become 'tougher' - it's that I've raised the level of expectation. 
LJ


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## Juhani Lunden (Oct 3, 2013)

little_john said:


> Sure - but they'd be drawing the wrong conclusions. I'm now *choosing* to increase the number of treatments - primarily because it's so easy to do with the latest kit. I don't really *need* to - it's purely that I *want* to - in the interests of keeping healthy bees.


Like TF
or IMP
or OAD
or IMHO
this could have an own shortening:
CITANW =*Choosing* to *Increase Treatments Although* they don´t *Need* t but I *Want*


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## Michael Bush (Aug 2, 2002)

>I would suggest that there is a higher concentration of honeybee colonies per given area of land mass in the United States than anywhere else on earth. 

Very doubtful. Even in a populated state like New York there are places very remote and unpopulated such as Hamilton County where there are only 2 people per square mile. Then you get out West where places like Cherry County Nebraska have less than 1 person per square mile and the county is 2/3 the size of New Jersey. Cherry county Nebraska is bigger than Connecticut, Rhode Island and Delaware... My guess is that All of Europe has a higher density of bees by what people there tell me.

Now one county in California every February has the higher concentration of honeybee colonies per given area of land mass than anywhere else on earth...


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## little_john (Aug 4, 2014)

Juhani Lunden said:


> Like TF
> or IMP
> or OAD
> or IMHO
> ...


Naughty, naughty ... :no:

I didn't say *they* don't need it - I said: "*I* don't really need to - it's purely that *I* want to - i*n the interests of keeping healthy bees*."
... and it *isn't* simply an increase in treatments - it's treating at the end of summer in order to ensure the production of healthy winter bees - thanks to Samuel Ramsey we now know the importance of this.
LJ


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