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Is it tougher and tougher to control mites with OAV?

14K views 70 replies 28 participants last post by  little_john 
#1 ·
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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#4 ·
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.
 
#7 ·
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.
 
#8 ·
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?
 
#9 ·
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
 
#66 ·
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."
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
 
#10 ·
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!
 
#11 ·
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.
 
#12 ·
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.
 
#51 ·
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.
 
#15 ·
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?
 
#14 ·
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.
 
#16 ·
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.
 
#17 ·
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?
 
#19 ·
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
 
#18 ·
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.
 
#22 ·
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.
 
#23 ·
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.
 
#24 ·
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.
 
#27 ·
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.
 
#28 ·
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.
 
#35 ·
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
 
#30 ·
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).
 
#32 ·
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. ;)
 
#33 ·
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
colonies to Sicily, where similar problems may
have been occurring, but precise data is
lacking, although resistant mites were later
detected.22 Resistant mites quickly spread via
bee movement into the neighbouring regions
of southern Switzerland, Slovenia and
southern France. From there it continued its
spread throughout Europe following
established colony trade routes in France22
finally reaching Germany in 1997, Finland via
possible bee movement from Italy in 1998
n 1997 pyrethroid resistant mites were
detected in the USA. Although the first
reports of resistance were from South
Dakota,1
it was quickly established that this
was linked to bees moved from Florida where
tests confirmed that pyrethroid resistant
mites were also present.6
Incidentally, Florida
was also the place where the original varroa
mites entered the USA in 1987.19 Florida is a
major bee breeding and distribution centre
with bee packages sent to all over the USA.
This has aided the long-distance spread of
both the original varroa and now their
pyrethroid resistant sisters. In only seven
years resistant mites have spread nationwide
in the USA
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
 
#37 ·
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.
 
#39 ·
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
 
#38 ·
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.
 
#41 ·
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.
 
#40 ·
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.
 
#43 ·
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.
 
#44 ·
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.
 
#46 ·
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?
 
#49 ·
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.

Mosier performed studies that demonstrate that the mutation does not protect against plague infection in mouse models and that it is unlikely to have offered any protection against the plague in humans during the Middle Ages. [perhaps against smallpox, or maybe a completely random mutation ?]

https://www.sciencedaily.com/releases/2004/02/040212083108.htm
Dunno whether there's anything more recent on this particular topic.
'best,
LJ
 
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