Deformed wing virus

Deformed wing virus (DWV) is one of the viral diseases associated with Varroa mite infestations. Although the disease is also found in colonies not infected with Varroa, it appears to be both more common and more destructive in colonies where mites are well established.

Other things can cause an occasional case of deformed wings and a diagnosis is impossible without laboratory tests. However, if you see a young bee with distorted, misshapen, twisted, or wrinkled wings, there is a good chance you are seeing the results of deformed wing virus.

In untreated hives, the Varroa mite population skyrockets in late summer and early fall. The mites had all spring and early summer to build up and now, when the drones are being evicted and the honey bee population is shrinking, the number of mites may overwhelm the number of bees. When the viruses also become concentrated in the remaining bees, symptoms are more likely to be apparent to beekeepers.

Bees with deformed wings do not live very long. The one shown below wandered out of the hive this morning and was fluttering her misshapen wings and running in a circle when I found her.


A honey bee with severely deformed wings


  • I have noticed some drones with DWV but have not noticed any workers. I opened up a few drone cells and have noticed a couple mites here and there but by in large most of them appear clean. This is the hives second year after going the first year treatment free (caught a swarm last spring).

    • Evan,

      Since you know mites are in there, you should consider some management technique, such as removing drone brood or breaking the brood cycle. Those mites will move from your drone brood into your worker brood in the fall, so be on the alert.

  • Hi Rusty,

    I found a couple of mites on some drone brood I inspected a little over 2 weeks ago. I have done a powdered sugar dusting on both of my colonies the past 2 weekends (both are newly installed nucs, 1st week of May). I only left the mite boards in for a couple of hours on both hives for both treatments. Combining both sugar treatment numbers: hive 1 mite board had 14 mites and hive 2 had 9 mites after sugar dusting. Again, I didn’t leave the mite boards in for 24 hours, just for a few hours as the temps in East TN now are upper 80’s and about 80% humidity. I’m sure my mite numbers are higher.

    Yesterday I noticed about 8 worker bees outside one of the hive boxes walking around with deformed wings.
    Contemplating my next steps and wondering how concerned I should be over these bees with deformed wings. Would you continue powder sugar dusting or a different approach? Also is there any treatment for DWV outside of lowering the number of Varroa?

    I would like to stay away from chemical treatments, as naive as that may sound, but am not opposed to a soft treatment if absolutely needed (Api Life Var, Apiguard, can’t get Hopguard2 in TN yet).

    Any advice would be greatly appreciated.


    • Jon,

      Your mites counts were high. Even if you hadn’t seen DWV, I would say you were in trouble; the DWV confirms it. So, what to do? According to Randy Oliver, who has experimented extensively with powdered sugar, it will do the job as long as you dust every frame every week. This gets old after awhile and it’s disruptive to the bees. What I’ve always done is use one of the soft treatments, as you suggest. I rotate between ApiLife Var (thymol), MAQS (formic acid), and HopGuard (hop beta acids). Rotating lessens the chance of developing resistance. If you can’t get HopGuard, you can use the other two or also oxalic acid (not listed in the US, but readily available in the form of wood bleach).

      There is nothing you can do for DWV. It rarely transmits between bees except through the bites of mites, so it will not move from bee to bee unless you have mites. The bees that already have it are doomed.

      Mites are a part of beekeeping life these days, so you have to develop strategies that you can live with. In addition to those mentioned above, you can remove drones from the hive (drone trapping) and you can sequester the queen for a few weeks to break the brood cycle. Making splits also helps as it also breaks the brood cycle.

  • Thanks Rusty,

    I like what I’ve read about Apilife var so that is the route I will likely go. Unfortunately it’s hot and humid right now here in TN so that makes the use of a fumigant a little tricky. I’ve been told Hopguard 2 should be available here in the fall and thats another soft treatment that sounds promising based on your articles and what others report. For now I will continue to dust with powdered sugar. Also supplementing sugar syrup w/HBHealthy. I’ve ready several of Randy Oliver’s articles about dusting and was very glad to find that it definitely knocks the mites off. How thoroughly it works is yet to be determined in my opinion.

    Do you have any experience with or info about fogging with FGMO for varroa control? Would be interested in your thoughts on this.

    Thanks again, as a new beekeeper your site has been extremely helpful.

    We are definitely on an uphill climb but I believe beekeepers are passionately stubborn enough to keep climbing. It also doesn’t hurt that honeybees are an incredible little creature with an amazing ability to persevere in spite of so many obstacles.


    • Jon,

      I don’t have any personal experience with FGMO, but here is an article written my one of my associates and it includes interesting photos.

  • I just noticed 7 or 8 wasp on my garden walking. They all have one wing and the other is small or shriveled. These are definitely wasp and has it been reported about wasp having this problem. As far as honey bees I’ve only seen 3 all season…

      • I live 20 or so miles north of Philadelphia and my neighbors and friends from surrounding communities said they have been seeing them too. I’m not sure how widespread it is, but the bee populations this year are as low as I ever saw. In fact only 3 that I can recall on my flowers.

        • Penn State is doing much of the research on CCD and other bee problems, at the Center for Pollinator Research.

          This might be of interest to them or they may have some info on it. Many wasps are also pollinators and this could indicate that DWV has jumped species or that there could be an environmental issue at work.

          The director’s name is Dr. Christina Grozinger.

          Their number is 814-865-2214.

          Email is cmgrozinger@psu.edu

  • This morning I went out to watch the bees and noticed that bees were dragging out dead pupa with deformed wings and they didn’t have any mites on them. I did a sugar role test last week and saw no mites. If they do have deformed wing virus is it treatable? I have pictures if you would like to look at them.

    • Elisabeth,

      I wouldn’t expect dead pupa to have mites on them. The mites will move on to live bees so they can extract their hemolymph. Deformed wing virus was around long before varroa mites, but it used to be more isolated and unusual than it is now because the mites help it to spread. Like most viral diseases, deformed wing virus is untreatable. If you are confident that your bees don’t have mites, then there is nothing more to be done. The bees are doing what they are supposed to be doing by removing deformed or damaged brood.

  • Can you see the mites with glasses? I have dwv I think. I don’t see any mites. I looked at the bees with a loupe I can see grains of pollen with it. I have no mites.

    • Jane,

      Varroa mites are big enough to see without magnification, but that’s not the problem. First they are seldom on the adult bees, and even when they are, they can hide between the segments where they are difficult to spot. You need to do a sugar roll test in order to estimate your mite load. Although you can have DWV without mites, it is unlikely.

  • I have DWV. I don’t see any mites. I used a loop I can see grains of pollen. I should be able to see mites but I don’t see any thing. How can I help my bees.
    Thank you.

    • What is a sugar roll test? how to do it? Are my bees going to die if I get rid of the mites.Im still finding 10 bees a day out side on the ground.I have treated twice should I keep treating?my friend and I are ready to give up on bees but I want to keep trying at least 1 or 2 more times not defeated yet.Are Russian bees stronger to this virus?

      • Jane,

        1. I gave you the link to the sugar roll test in the previous e-mail to you.
        2. The link explains how to do it; just follow the directions. It will not hurt your bees.
        3. I don’t know if your bees will die if you get rid of the mites, but they will probably be better off. By the way, ten bees per day is nothing. On a normal summer day, a healthy colony will lose 1000 or more. You just notice them more in the winter because they die closer to home.
        4. You say you have treated twice. Read the directions of the product you are using to know if you should treat again or not. Directions are usually on the side of the package and should be followed to the letter. Since I don’t know what you used, I can’t answer the question.
        5. I don’t know that Russians are more resistant to DWV. I haven’t read anything one way or the other.

  • Professor Klaus Wenzel published a paper in the last issue of The Beekeepers Quarterly which reviewed the most current research on bees, DWV, varroa and neonicotinoids. He elucidates the work of Dr De Prisco’s team in 2013 which confirmed the following:

    1. Deformed Wing Virus and Nosema Cerana are ‘endemic’ – present at all times, in just about every single honeybee colony on the planet. Varroa is also present in just about every colony.

    2. In healthy, robust colonies, these pathogens (DWV and nosema) are normally benign – like the coldsore virus in humans, they are always present but they do not normally manifest.

    3. Similarly, although varroa is a nuisance, there are very few records of varroa, on its own, killing healthy colonies.
    However, varroa has become more ‘lethal’ since the 1990s; a mite count of 2,000 or more was generally not lethal in 1998, but a mite count of just 500 is usually a sign of imminent colony death in 2016. How can this be?

    3. De Prisco’s experiments found that when neonicotinoids were added to the equation, all became clear as day.
    When colonies were exposed to field relevant doses of clothianidin (used on 200 million acres of US crops) – the replication rate of Deformed Wing Virus DNA in those colonies was increased by a FACTOR OF 1,000. The situation with Nosema was the same; it changed from a benign, hidden fungal pathogen into an explosive disease which killed the colony.

    The varroa burden of the control colonies and the neonic exposed colonies was the same. In the control colonies, the bees continued to thrive, despite the varroa burden. In the neonic exposed colonies, DWV and Nosema suddenly appeared and grew exponentially, as did the varroa count.

    Dr Wenzel concluded that exposure to even the most minute dose of neonicotinoids destroyed the bees natural immune system defences, and catalysed the explosion of DWV and Nosema, turning benign, hidden pathogens into colony killers.

    He also stressed that it was ‘biologically impossible’ for varroa mites, on every continent, to simultaneously evolve to become 4 times more lethal than they were just a decade ago. It just does not add up, until you add in the neonicotinoids/ immune suppression factor, which turns varroa into a colony killing virus carrier (DWV).

    Confirmation of this hypothesis comes from studies of bumblebees, which are dying at a much higher rate than honeybees in areas where neonicotnoids are present. Bumblebees are NOT parasitised by varroa but they are dying from DWV, Nosema and other infections in uncountable numbers – because their exposure to neonicotinoids destroys their immune systems – just as in honeybee colonies. This is the crucial insight which reveals that Varroa is merely an ‘accomplice’ – an accelerating factor – in the death of bee colonies; but the real killer is immune system suppression by neonicotinoids.

    The Wenzel paper is published in the Spring 2016 edition of Beekeepers Quarterly. The De Prisco study is available online here: http://www.pnas.org/content/110/46/18466.abstract

    “Honey bees are exposed to a wealth of synergistically interacting stress factors, which may induce colony losses often associated with high infection levels of pathogens. Neonicotinoid insecticides have been reported to enhance the impact of pathogens, but the underlying immune alteration is still obscure. In this study we describe the molecular mechanism through which clothianidin adversely affects the insect immune response and promotes replication of a viral pathogen in honey bees bearing covert infections. Our results shed light on a further level of regulation of the immune response in insects and have implications for bee conservation.”

  • The Klaus Werner Wenzel paper is available free online here:

    “Recent research has clarified certain biological phenomena, which previously we could not explain. Generally, it is the sub-lethal effects of systemic pesticides, mainly Neonicotinoids, which damage or destroy the bees’ immune response. As far as the Varroa mite is concerned; there is no scientific proof that Varroa causes the collapse of honeybee colonies, as claimed by the agro-chemical lobby and many official institutions in Germany. Varroa mites clearly live as parasites in honeybee hives, where they may weaken bee larvae, but they do not kill colonies. They may contribute to bee deaths indirectly, by infecting bees with viruses and bacteria via their bites. However, such endemic infections may already exist within the colony, as was proven for the potentially deadly DWV, since both the eggs and drone sperm can already be infected with the virus. Such endemic infections in the past could also explain why DWV is to be found in almost every beehive worldwide. DWV exists chronically and covertly within healthy bee colonies, but DWV only becomes virulent and deadly when direct immune suppression is triggered by NN (Di Prisco et al. (21):”

  • I had it last year; I know what it looks like. It depleted my hive. I’m just hanging on; hoping it can make a come back. Queens not laying much, hardly anyone left to take care of the brood. Took one hive off better chance if hive is smaller, not so many robbers and a lot warmer.

  • I am based in Auckland, New Zealand. I think my girls are in big trouble. They have been doing sooooo well since I got them last November. Treated November with Apivar and March with Bayvarol. The climate is considered temerpate in Auckland over winter, and they have raised drones all winter. The activity has been very high, so much pollen and full abdomens coming in, lots of orientating bees every lunchtime. But over the last few days there have been a lot of newly hatched with deformed wings. About 20 discarded per day, at least. And I don’t have any Apivar cos I thought I had until 1 st September to start treatment. So won’t have that til Thursday ass I had to buy online. And hope the weather is OK to put it in. What are their chances of surviving this? I haven’t seen any mites on any bees coming in or out (I look at the foragers closely and catch drones and look with my 3.0 spectacles) But I haven’t opened for 4 weeks because it’s been cold and as I say, from the entrance everything looked great. Your experiences in bringing a hive back from DWV appreciated. Or should I order another nuc now? Thanks

    • Valeria,

      Mites are not something that you would normally see on your bees. Most mites, up to 80 percent of them, can be hidden inside of capped brood. I never see any mites at all until I treat, and then I see them drop off in great numbers.

      Since you have temperate winters and you have brood all year long, you can raise a lot of mites between treatments. With no winter brood break, you need to treat before you put on honey supers and then again after you take them off.

      That said, if your last treatment was in April, that was only four months ago, so I’m surprised you are seeing so much deformed wing virus. Did you check the expiration dates on the packages? Did you follow all the directions?

      It’s not obvious to me what’s going wrong. Still, if you treat soon, you may be able to overcome it because your bee populations will be building up for the season. Normally, once the mites are under control, the virus disappears because the bees don’t transmit it themselves.

      My guess is that your bees will make it, but do write back and let me know how it goes.

  • Thank you so much for your reply, Rusty, I will certainly update you in about a month. I was neglectful after my last treatment as I did not sugar shake to determine efficacy. Maybe the remaining mite load was still too high. I did follow all treatment instructions and left it in for correct amount of time, as per local beekeepers’ advice so carelessly presumed all would be OK. Today, when I put the new treatment strips in I will try to do a sugar shake so I know how bad it is before and then will definitely do one after the treatment period. Again, my sincere thanks for your advice and this blog.

    • It was 2 years ago I wrote about DWV in my area..I appreciate the replies. The problem now here north of Philadelphia is no honey bees, none. I haven’t seen one bee this year, and only 3 bees last year..Truly concerned..
      No Monarch butterflies for 2 years either..

  • Does anyone on this page has any experience with bumblebees as well? I work on Bumblebees with my team. We breed them under controlled conditions. Recently we have seen some workers and drones with deformed wings. I thought its DWV disease but I am not entirely sure. Because the bees affected by this happen to survive very long (pretty much normally), while according to research papers I read, their life span is reduced drastically. Could it be any other disease? Can someone please help me.

    • I don’t think there is an answer. I do know one thing: I will kill my own bees with nuclear waste before I let the varroa mites win again. I put my second dose of apiguard in today. I don’t know what to nuc them with next.

  • Rusty-

    Thank you for all of your knowledge and wisdom about the bees!!!!! I am a first year beek and am in a pickle…. (I live in the Hudson Valley, NY and it is September 11 as I write to you). I have 1 hive of Italians and they are doing very well but I did notice mites on my bottom board and I did an oxalic dribble on September 4. Yesterday I noticed about 16 young bees walking around on the ground and they could not fly. I am thinking about treating the hive with Formic Pro strips so the capped brood can get treated as well. Here’s the kicker to my issue, I have been fighting off yellowjackets and robbers as well! I know that with the formic strips the entry way needs to be completely open for a week for ventilation but I am concerned about keeping it totally open because of the yellowjackets! Do you think that if I have a robber screen on the front, it will be ok? I just don’t know what to do. I’m stressing out. If you can give my any advice I would so greatly appreciate it! Thank you!

  • The best thing I have found to test for veroa is a bottom board that you can pull out every day and count them.One of my hives I have been fighting veroa all year I count from 300 to 150 veroa a day I have used Apiguard for 21 days in spring in June I used mite away killed so many I would guess it was around 1000 for two days then it started to climb back up in Aug.I used Mite away again,7 days after treatment I used Apiguard again.Im on my 14th day time to change the meds. still getting 150 veroa a day.I have never lost a hive from winter kill, starvation or condensation or any thing else except veroa . You may think its winter kill but I bet its veroa ,it kills so many bees it cant keep the Queen warm in the winter and they die, and even if they do make it to spring ,when you look inside you may see a baseball size group of bees and the Queen laying multiple eggs in a cell ,the nurse bees can not take care of the number of eggs she is putting out so she puts them close together.What I did was merge two frames nurse bees with brood and in about a week or two I had a good hive.But year after year I lose hives to veroa k wing.I treat and treat nothing stops them.Larger hives seem to be taken down more then small hives. I have one hive every time I treat a good lot of the bees stay out side of the hive when the fumes go they go back in the hive.That does not help me they just bring them back in.Well good luck to you bee keepers and get removable bottom boards they are the best thing ever to check for veroa ,put oil or Vaseline on the bottom tray and they get stuck to it ,count the veroa if you have more then ten veroa on the whole bottom board time to treat.

  • Jane – I feel your pain. Being a second-year beekeeper I’m still well on the “learning-curve.” Varroa mites were not on my radar screen. Last year we lost two hives to yellowjackets. Hence, my focus this year was to try to keep our bees alive through wasp season. The year was so successful we produced two hives from a single package. Our June flow gave us a nice honey harvest in early July and then another large harvest came in August. I recall seeing a few mites cleaning bottom boards at time of harvest but not until early September were they obvious. I organized treatment (oxalic acid fumigation) as rapidly as possible. First treatment was Sept. 12. We saw 360 and 150 drop from those treatments. Following counts went down in the hive with 360 but up significantly in the hive that had the initial lower mite count. A second treatment – 5-days later – saw 565 and 658 on the count boards after treatment! I was not expecting that. Nor did I expect our best and largest hive had the count go up to 825 two days after treatment and remain high (400). Now, today we witnessed our first emergence of bees with wing deformities. Enough of them to suggest our best and largest hive might be in serious trouble. Treatment 3 commences tomorrow. I can only wish we see some kind of decline in mite count. Each day is learning episode. Daily counts help me evaluate the efficacy of oxalic treatments. Stressful because our bees could not have performed better this year and so far yellowjackets look to be less of a problem – due likely to an intense control effort. Nearly 4,000 killed to date. I want to see these hive survive to winter and hopefully through to spring.

    • Oxalic kills some brood. I was told to use it when they stop laying. Right now I’m using MiteAway strips. It works good. But like the oxalic, it needs to be repeated until they are gone. Best time for the oxalic is November when they stop laying and once more in December when they stop flying. Do you put Vaseline or oil on the bottom board? If not try it it will give you a good count.

      • For yellowjackets try cutting a coke bottle one third of the way down, flip the top over so the top is now facing down, fill the bottom up not touching the hole at the top. They will try to go in and they will drown. Fill it about 2 or 3 inches from the hole. Hope that helps some!

        • Jane – for those who don’t know the coke bottle trap is a good one. I have not tried pure Coke but will. I have run wasps traps since July 24. I have a vengeance for them. They killed two hives last year – one a weak swarm but the other a well established hive which was our first attempt at raising bees. This year I used pheromone traps for most of the season then added something similar to our coke suggestion. In my case they were 1.5 litre jugs with two holes drilled in them to let the wasps in. I would take a commercial pheromone lure and split it into 3 equal parts making 3 traps. These filled the jugs to only about 1/2 inch off the bottom but deep enough to drown the wasps that entered the trap. The lure gets expensive when using is all season – I even put traps in neighbours yards. Later in the season I tried several other baits. The best to date has been balsamic vinegar, sugar, banana peel, and a few drops of dish soap. This bait after a few days captured more wasps than did the pheromone. This sounds a bit over-board, but yes, I have counted wasp throughout the season. Again, more for learning but also for vengeance. Total is to date 4085 wasps. Average kill rate is 60 wasps/day with 70/day being high season. A friend lost two hives to wasps this summer. I also trapped in early spring killing 25 queens which suggests another 12,500 – or any upward number if each queen produced more than 500 offspring which is all too likely. You can see why I’m especially sad about messing up on mites. But, fair to say we learn by Doing and why the information given by Rusty, you and others is so helpful. Bees are far from easy.

  • Within my beekeeping group (based in Auckland, New Zealand) I am the only one that uses chemical treatments such as Apivar & Bayvarol (alternating) – the others all use alternative treatments such as oxalic acid, MAQs etc. I’m the only one that hasn’t lost a hive to varroa. I feel sad for my beekeeping friends but I just think that the mites are so strong nowadays that it takes chemicals to rid the hive of them. People can be successful with alternative treatments but they have to be super vigilant and they have to be prepared to strictly follow all instructions, including following temperature guidelines, frequency, monitoring etc.

    • Valeria,

      I agree. It seems that the concentration of viruses is getting worse, so the same amount of mites nowadays inflicts even more damage than it used to. You are correct: super vigilance is important.

    • I agree with you I keep trying to stay somewhat organic but may need something stronger. Maybe the Apavar. Does it work well?

      • Hi Jane. I am in New Zealand and for me Apivar still works wonders. I have brought two hives with DWV back using it. The alternating chemical treatment I use is Bayvarol but mites are getting resistant to it here. So the normal practice is to use Bayvarol for autumn treatment and Apivar for spring. However, whenever I use Bayvarol my hives are in trouble about 8 weeks after treatment finishes. Therefore I have to assume Bayvarol is failing. Unfortunately I have no other effective chemical option but to use Apivar for every treatment period. This is not ideal and presents the risk of resistance but I have read that resistance is less likely with the action offered by Apivar. I am going to make sure to give each hive a brood break every year by splitting. I will also cull drone brood occasionally using a drone trap, although I really hate killing my boys 🙁

        • A very active discussion that is greatly appreciated. My situation looks grim. I chose oxalic acid as a treatment option 12 days ago (Sept 12) not fully understanding the alternative choices. Our treatments have been effective, but never did I expect mite numbers to be so out-of-control. Presently into the third oxalic acid vapour treatment – it is doing its job but still hundreds of mites being dropped. I can see now it’s likely too late to save such infested hives.

          Our largest and best hive had 20 DWV bees show up at the door and a second formerly strong hive 2 DWV bees. These seen in the last 3-days. Reading all of the valuable information provided by each of you has been greatly appreciated. I questioned myself about mites in mid-August after removing a honey harvest but sadly got put off by a comment from a local beekeeper who said he was treating his hives at the end of September and would give us a hand if we needed. Oddly, I became nervous about that idea and decided to be more “pro-active” and started a treatment program sooner, Sept 12. Little did I know I was already 3-4 weeks late and had I known the risks I would have selected a much faster treatment option – such as a 7-day formic acid prescription.

          Unfortunately, with animal husbandry it takes experience. Emerging beekeepers are acutely vulnerable to these kinds of issues. Mites, DWV, even yellowjackets! Painful to think after all of the year’s best efforts a problem like this would occur. Maybe a few of our bees will make it through the coming winter, but not counting on it. Next year thanks to the well articulated posts by each of you my IPM options are much better understood. Spring care, splits, drone control, early intervention, and close monitoring are now in the tool box. Thanks greatly.

          • Keep trying, don’t give up. If you have to for the winter, if you still have a queen, if the hive [colony] is too small to keep the hive warm enough for the winter, move all the food to one box. It’s easier to keep one hive warm than two, only use one hive I have saved hives with small amounts of bees before, but in the spring you might need to steal one or two frames of brood with nurse bees to give the queen a boost. That’s all. She really needs and the hive will be strong again.

            • Jane – it looks like I came to that decision this morning – no bees flying from what was our most heavily infested hive with mites. 68 mites on the drop board yesterday (1-day post Treatment 4) and 14 today – but no bees moving this morning at 10 am. Buzzing in our other hive, but no buzz in this one. Tomorrow if warm will do a hive check, but the lack of mites also suggests what I’m seeing is very low bee numbers. Our second hive is down from 190 to 100 today and is active. The issue is both hives came down with DWV which is why the infestation is especially serious. Combining the hives now is a good suggestion and I think the only remaining option. That assumes I still have some bees alive. It is impossible to tell whether the bees were affected by the treatments themselves, DWV, or degree of mite damage done to them. Most studies seem to suggest bees can handle oxalic acid treatments. I mistakenly used it too late in the game and more than likely would have had better chances of controlling things with an alternative method. But your experience shows all treatments are subject to less than great results. I dragged feet to long for lack of fully understanding just how to go about the various treatments. It won’t happen again. The hive I am about to loose was an amazing population of bees. It grew to huge numbers and produced well over 80 pounds of honey either harvested or stored – all of this coming from a split and why we still have one hive left.

        • Thank you I just got some Apivar. I’m putting it in tomorrow hope it works! Why do you use it in the spring and the bayvarol in fall is there a reason?

      • I’m going to try it, I have no other option. I just lost a hive to MiteAway strips. It was so strong the bees swarmed. I caught the swarm, put them in a hive, they did not like the hive and they flew back to the original hive, it caused a war and they were killing each other. I’m not sure who won but I hope it was the mated queen because there are no drones around this time of year. I have a feeling the hive is lost. It also killed some brood and bees. So what they tell you is not true. Does Apivar kill the bees? Or brood? thanks for your help.


  • Wow, did I learn that!!!!! Next year the day after those honey boxes come off treatment will start. I’ll never let a week go by without keeping track. All the advice here has been super helpful. Thanks greatly.

  • Hi again. To answer Jane’s two questions: 1) in New Zealand the protocol is to alternate treatment chemical types to prevent resistance however, also said, in already finding resistance to Bayvarol so may just have to use Apivar for both treatment periods.
    2) Apivar doesn’t appear to have any negative impact on the bees or their colonies.

  • There is a lot to read.

    Is there a time period we should stop seeing dwv after treating with formic acid?

    The temps have been down so I didn’t do a second round but am still seeing dwv after weeks of treatment.

    • Jim,

      Imagine you got bit by a mosquito and contracted malaria. You can kill the mosquito, but that won’t cure your malaria. Right?

      Well, the bees got bit by a mite and contracted deformed wing virus. You can kill the mite, but that won’t cure the deformed wing virus. When all the bees that contracted DWV have died, then you won’t see it anymore.

      • I have been fighting mites all year. I used Apiguard twice, the mites were multiplying, it did not work at all. Then I went to MiteAway strips. I used it three times and yes it did kill a lot of mites the first two days but also killed some of my bees and although they say it does not kill brood, two of the three times I used it there was live brood on my bottom board and my bees swarmed twice when I used it.

        The bees did not like that and I still had mites over 100 a day. It’s easy to count with a removable bottom board. Than I used HopGuard did not work at all. Now I’m using Apivar still have mites 42 days will be Sunday. It’s hard to say if it works or not because it’s late in the year and they have almost completely stopped laying eggs so my count would be lower. Still counting about 100 a day. If this is the case nothing works and nothing is killing the mites. I would bet you still have the mites, when I was checking the drone brood it looked clean then we got a bottom board I was so wrong it was loaded. All I can say is good luck.

    • Valeria, I have used all these things this year and I still have a count of 100 mites a day. My Apivar treatment is almost over, still have a lot of mites, never used it before, the bees did not mind it at all. I have never used Mite Away strips till this year or HopGuard. Apiguard was the only thing I have used, it won’t work any more. Acid is next. That is the only thing I have left to try nothing else has worked. I count daily, I am going to give up if they don’t come up with something that will kill these things. I’m not going to get into splitting my hives. Yes it does knock them down but does not get rid of them. My friend and I are disappointed in the products out there, she sees it too. We’re both ready to give up. Do you have any more ideas? I’ll try most any product. Thanks for the help.

      • Hi Jane. I’m sorry to hear how difficult it’s been for you to get rid of mites. I’ve always found Apivar to be the best so far. Not trying to be patronising, but are you sure you are using it correctly? Fresh strips that have been stored correctly? Inserting correct number of strips into centre of all brood nest boxes where all nurse bees will crawl over them? In New Zealand the general consensus is to leave them in for 10 weeks but not longer than that. I feel the same as you though, if nothing better is developed then it’s only a matter of time until I think about giving up this losing battle. Let us know what you have success with. Good luck!

  • Hard lessons here. I lost the battle with my two hives due to mite infestations. Wrong treatment and not early enough to minimize the impact of DWV. Then came Nosema which was the last straw. We start fresh in spring with an expanded outlook on IPM.

  • Valeria,

    Hi. I put the Apivar between the frames over the brood chamber two frames apart top and bottom box. They said 42 days no more than 52 days. I don’t know if they sent it fresh or not but I image they did. Mite-away strips work the same way but I think it was seven days. I can’t remember. I heard you’re having troubles with the mites. I have a removable bottom board; it has a grid to count the mites. It’s easy and it works great. In the past I saved my hives by stealing a couple frames of brood and merging them together with newspaper. I had such a small amount of bees they would never have made it, it did end up being one of my strongest hives. If you still have a queen and you can put them in one box instead of two and keep her as warm as you can, she might make the winter then you can merge them. All that was left in my hive in the spring was a baseball-size group of bees and they made it. Good luck, just food for thought.

  • Wow. I thought I was the only one these posts. Sound just like what I’m experiencing. Spent all weekend trying to get OA stuff together big strong hive mites all over bottom board still fighting

  • Paul Stamets says he has found the solution and apparently has patents in the works. Mushroom Extract. Call it crazy. Mushrooms love decaying timber. Bees will naturally nest in decaying timber. See a connection? Paul did. Tested it. Proved it. Research it for yourself.

  • Last year I had 100 mites in my bottom board I did battle I won and I’m mite free. Oxalic acid vaporizer 1/4 teaspoon per deep put it in turn it on clog up whole leave it in for ten minutes. Take it out and you’re done once a week for one month. Best time to do it is in the winter 45 degrees it can be done and its a good time there is no brood so you kill them all. Again once a week for one month. Just be careful not to catch the hive on fire. The new packages are coming in with mites 5 out of 5 from different places came in infested with mites so by July you have a problem. When I got mine in I vaped it 110 mites off one package, I told my friend to check his he had them too we both have bottom board with draws we can pull out and look. This is why we are having so much trouble. None of the other chemicals work. Oxalic dosen’t seem to bother the bees much. I do it at night so all the bees are in the hive. Hope this helps keep your bees alive I have been trying real hard to find the answers I think this will salve most of the problems. I also in the sugar water give my bees chaga tea they love it and from what I read its really good for them 90% less virus. This is all my studies try it i think you will like it.

  • Hi Rusty, new to beekeeping 2nd year. Lost 2 hives 2017 over winter. I started spring 2018 with a package for just a single hive. I’m in transportation support so gone long stretches at a time, so just treated for mites on 9/7 with Miteaway quick strips. Sitting watching my bees tonight, I see there are bees just emerging from the entrance, basically being drug out that have deformed wings. I’ve read a lot of your posts and great information, just wondered if there is any chance of the hive surviving this winter? I’m sure these are the winter bees hatching now and will they all have the DWV? I live in northwest Wisconsin. Thank you for all your information.

    • Mary Ann,

      It’s hard to say how many will have the virus. Now that you’ve treated the hive, just make sure the other pre-winter preparations are done and hope for the best. That’s all you can do it at this point.

  • The odd thing about finding a bunch of deformed-wing bees in my last inspection is that this was the hive with the long brood break cycle (walk away split). I think another stressor may be to blame, such as poor ventilation and/or really cold nights. I’m on the other side of the Cascades from you, Rusty.

    • Marty,

      You have to consider when the split was. If it was back in spring or early summer, the mite population has had plenty of time to re-establish itself. Poor ventilation or cold nights could cause problems in a hive, but they will not produce bees with the symptoms of DWV.

  • Marty, try chaga mushroom in your sugar water. It has been studied 90% less chance to get deformed wing. Also I would guess you have mites. Try a beetle bottom board and put Vaseline on the board that’s what I use. Get one that the bottom pulls out you can do a count with out all the hassle of pulling drones and sugar shake it really works. Splitting the hive just brings it from one hive to the other. I bought a hive this year it was infested with mites when I bought it by July. If I did not treat it when i got it all most of my bees would be dead. My friend did not treat his hive and his hive is now dead. Last year I was pulling 100 to 150 mites a day out of my hive. I had a bee man come over and pulled 1 dozen drones none had mites on them but my bottom board said different 100 different. When I got rid of the mites the virus went away within about 45 days. People tell me they had winter kill when I look in the hive there was a small ball of bees not enough bees to keep the hive warm. Mites were the real killers knocked the hive down so far they could not keep warm. I tried apivar. It knocked them down then in the winter oxalic acid vaporizer on warm days once a week for four or five weeks till there are no more in site. Hope this helps you. jane

  • Hi Rusty,

    I have a question not associated with this post, but haven’t found any information on your blog so I figured this would be the closest place to ask a question.

    I keep bees in southern Oklahoma and noticed a bunch of dead bees outside the hive that had small abdomens, as though their abdomens weren’t fully developed. Do you have any idea what it could be? I treated using Apivar strips once in the summer and once in late fall. They’ve had a hard summer with the high temperatures. I requeened the colony mid summer and combined them with another small (but strong) colony in mid October. My mentor and I are a bit stumped on what it could be, maybe you can help guide us? Thank you!

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