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Improving Honey Bee Health For Backyard Beekeepers and Varroa Mite Treatment ft Dr. Dennis van Engelsdorp

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Show Notes

Join Nicole and Dr. Dennis van Engelsdorp as they talk about ways to improve honey bee health and learn more about varroa mite treatment.

What You’ll Learn

  • How to keep our colonies healthy
  • Choosing the best varroa mite treatment
  • Integrated Pest Management practices

Our Guest

Dr. Dennis van Engelsdorp is the Associate Professor of Entomology and honey bee researcher at the University of Maryland, focused on improving honey bee health for backyard and small-scale beekeepers.

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    Announcer: 0:01

    Welcome to the Backyard Bounty podcast from when we talk about all things backyard poultry, beekeeping, gardening, sustainable living, and more. And now here's your host, Nicole.

    Nicole: 0:17

    Hello, everybody, and thank you for joining us for another episode of Backyard Bounty. I'm your host Nicole, and today I'm excited to introduce Dr. Dennis vanEngelsdorp. For those of you that don't know him, he's the Associate Professor of Entomology at the University of Maryland and a honeybee researcher. And if that wasn't enough, he's also the founding president of the Bee Informed Partnership. So Dr. vanEngelsdorp, thank you so much for joining me today.

    Dr. vanEnglesdorp: 0:42

    Well, thank you very much for having me.

    Nicole: 0:43

    Absolutely. So you have an incredible history. If anybody Google's your name, there'll be no shortage of articles and interesting things to read and TED Talks to listen to, and I actually stumbled across you in the Cornell Master Beekeeper program, where you had a lecture about how we need to be treating our bees, and it was really insightful. And so I was really excited when you agreed to come on to the show because you just have so much fascinating research and information. And I know that you are most interested in honeybee health and disease.

    Dr. vanEnglesdorp: 1:18

    Yeah, that's right. And so just as a little background, you know, I'm really lucky to be able to work on such an exciting system, right, like honeybees are cool. I mean, everyone takes the opportunity to open a hive of bees and hold that frame, you know, with those 30,000 workers in that colony, 50,000 workers, they're doing their magic, they're making gold, you know, the sun is shining... there is nothing more meditative and awe inspiring than a honeybee colony. And so, I've been really lucky that I've been working with them all my life. But I've never been traditionally a very good student. And so I never thought I would do a PhD. And so it was only when I was the acting state, apiarist in Pennsylvania and my connections through Penn State that I realized, no, I want to do this research. And at that time, what was really amazing was I inherited all these historical bee disease records, back to the 1814s. And I started really doing some research about bee disease in America like when, like you, of course, honeybees aren't native to America. So they came over with the colonists, but different diseases came in afterwards. And you can go back to some of the original New York Times articles about bee disease or when Wax Moth came into the country. And so that was really, really quite fantastic to look at culture and our culture, working with bees, and how bee disease change that culture and changed things. So I was really interested in that. And I was really interested in what beekeepers could do to help reduce disease, but then CCD happened, and that took my attention. And so I certainly had been working on that a long time. But now again, I'm able to get back to looking at some of those historical disease records and trying to tell that story because it's a really fascinating one. I mean, Bees are fascinating. And beekeepers are nearly just as fascinating. And so that intersect is really exciting and interesting.

    Nicole: 3:07

    Yeah, I didn't even know that these records existed from way back when so what were some of the common diseases that plagued beekeepers back in the 1800s?

    Unknown Speaker 3:16

    Yeah, no. I mean, it's it's a really interesting story. And you can see this in different states and the data isn't very clean. So you really have to sort of look for it in archives and different things. But if you think about it, when the European honeybees first came over, they were on these ships, right? Like they actually moved them in crates, sitting these skeps on blocks of ice to keep the bees calm, and so they would come out on the sailing ships, which probably meant that most of the bees that were sick probably died before they got over here. So when honeybees first came, there weren't very many diseases or pests of these, as far as we can tell, but then when you had new diseases come, of course, these diseases would ravage across the state. So most of the apiary inspector laws and programs that are in the state, result as a result of the 1920s and 30s, when American Foulbrood first came into the country, and it spread really quickly, and so this required there to be laws, like it said, okay, you can't use non movable frame hives anymore. Before that everyone would keep their colonies in box hives or in skeps that didn't allow you to look for disease. And so it became a law that you had to move all your colonies into movable frame hives. And in Pennsylvania, they got a fine that would be equivalent to 1400 dollars today, if they didn't do it, or they could go to jail for two weeks. So they were serious about controlling this. There is one state in the center of Pennsylvania, if I'm recalling correctly, that had more hives burned because of AFB in one year than there are currently in the entire state of Pennsylvania.

    Nicole: 4:50


    Unknown Speaker 4:50

    So this was like 60-80% of colonies were wiped out when AFB first came. Of course, that's because this disease is very, very long lived. They have been storing spores of American Foulbrood for 50 to 70 years and those spores are still viable. And it only takes maybe less than 100 spores to kill the right age larva, but that, if it gets infected produces millions and billions of spores. So it's a very contagious disease. So looking at how these diseases and interact and so then we had American Foulbrood and you can see as you look down the list, then we had European Foulbrood introduced, Chalkbrood introduced, Tracheal mite, Varroa mites introduced, and as you look at the disease incidence over time, you see that every time there was a new disease, sort of the level of all the diseases increased. And so this is sort of what we're seeing today, too, right? Like we're always talking about it's not one thing killing bees. There's some primary drivers, of course, but it's sort of the cumulative insult of 100 cuts. And we can really clearly see that in that record. It's also fascinating because, you know, we right now are so used to seeing maps, pretty maps. colors you know to explain things back then it was a state apiary inspector who hand painted watercolor on a map in order to show disease and then back then we move bees by train or by horse and buggy and and there's all these, there were all these receipts of the inspectors returning train tickets as they were moving between counties in order to inspect bee colonies. So yeah, it reminds you of a great history sort of. And that's what's fascinating about bees of course is it's this you know, I you jokingly say it's the second oldest profession known to man. And that's because we've been beekeeping and fascinated by bees as a species for a really long time. And that's just amazing.

    Nicole: 6:42

    I never really thought about the history of beekeeping. I mean, of course, I knew they brought them over, but I guess I never really thought about the logistics of it. So I think that's really interesting.

    Nicole: 6:52

    I mean, it's, it's great because, you know, the more things change, the more they stay the same, right? So you look at these articles written a hundred years ago, and they're saying the biggest threat to beekeeping is all the beekeepers are old. And I've been to a lot of beekeeping meetings where they're saying exactly the same thing right now, you know. So yeah, it's fascinating. One of my favorite stories back there was when wax moth came through the country, a lot of people would blame their dead hives on wax moth. And this sort of grumpy, I guess, inspector once wrote, he says, saying your colonies died from wax moth is like shooting a horse coming back a week later and saying the maggots killed it. isn't that, a descriptive, a great way of describing it?

    Nicole: 7:39

    And absolutely correct. I would say that's great.

    Dr. vanEnglesdorp: 7:42

    Yeah, it's a really good analogy.

    Nicole: 7:44

    So looking at the history of these beekeeping diseases and things and with the research and information that you have, what are some things that we can do as hobbyists and backyard beekeepers and small scale beekeepers to help improve the health of our own hives?

    Dr. vanEnglesdorp: 8:00

    Well, that's a really good question, I will say. So I'm going to say some things that I know the data supports, and then some things that I think the data will support or we may discover soon. Okay, so the data clearly supports that it can be the accumulation of insults that cause colonies to collapse and to die. And so I think the take home message for that, is we need to keep our colonies as healthy as possible. And so how do we do that? That's not complicated. It's, it might be challenging, but it's pretty straightforward. We have to make sure they're well fed. And by well fed, we have to think about their sugar, their carbohydrates, so we have to make sure they have food all winter long. It has to be in a place that they can access because remember, these bees produce or form these clusters, and in order to move on to honey somewhere else, they actually have to move over that cold honey and heat it up and eat it. So we have to make sure that when we set our colonies up for the winter that the colonies are low, so they're going to move up on top of the honey and eat the honey, as it heats up and warms. If the honey is all packed to the sides, it's going to be hard for them to access it if there's a really small cold snap. So thinking about what we're feeding our colonies, of course, we should only feed our colonies if we're feeding them, we should only feed them sugar that is cane sugar, not beet sugar because you want to avoid starch and you want to make sure it's clean sugar so they don't get diarrhea. Of course, we also have to provide protein and it's this depends on where you are, but you want to make sure that when those colonies are building brood, they have a lot of protein. So maybe adding pollen patties or artificial feed for a while before there's a good pollen flow. The other thing we have to do of course is to make sure all our diseases are low so that means regularly inspecting for brood diseases, like burning colonies and destroying colonies with American Foulbrood, getting good quality queens that are hygienic in order to help control some of these brood diseases. And of course, controlling Varroa. And I can't over emphasize the fact that every responsible beekeeper needs to regularly monitor their mites and treat them as soon as you think they're going to hit three mites per hundred, you need to get those mite levels down. We have growing and ample evidence to say that if those mite levels get above three, that it's going to dramatically increase the chances those colonies die. And that's of course, because of the viruses they transmit. So keeping your colonies well fed and well nourished, making sure that that diseases are low, especially Varroa. And then of course, making sure as much as possible to protect them from pesticide exposure. So being really deliberate about what products you're putting in the hive to control your your mites, and also encouraging people to only use pesticides if they're needed.

    Nicole: 10:54

    And as far as my treatments, do you have any recommendations on ones that you would feel like are more effective or are safer for the hive?

    Dr. vanEnglesdorp: 11:04

    So that's a really good question. We had something published based on the Bee Informed Partnership data earlier this year, or last year, I guess. And what it showed was it's a little bit different for different types of beekeepers, and it's a little bit different depending where you live. And so my general recommendation is that you need to have more than one type of control applied in a year. In northern states the people who are most successful applied four different treatments, and they were different treatments at different times of the year. And so I think you want to alternate and again, you have to figure out what's your own personal preferences if you're willing to use hard chemicals and synthetic chemicals, starting with sort of a hard chemical just before the honey flow. Then in the middle of the season, when there might still be honey on using an organic acid like formic acid, then in the fall using an essential oil like Thymol and then cleaning them up with an oxalic acid trickle when they go broodless. But of course, if you're in southern states where you have brood all the time, your your plan is going to be different. And so you really need to look to your local organization or look on the web for what is appropriate for you. A general guide is you need to monitor your mites every month. And if they get above three, you need to do something. You can also always have some things installed that help reduce mite growth. So there are things you can do to put in your colonies that slow the growth like screen bottom boards, there are management practices, you can employ like drone brood removal, where you put in a sheet of larger celled brood comb, where the Queen can lay drones and if you take that out every 24 days and put it in the freezer overnight, because mites like drones better than workers, it acts as a sink for mites and so you can sort of flush them out. Again, you can't get away with no treatment with that but it reduces how many treatments you need and the space between. Another really good thing for controlling mites is just when you're increasing your colonies, the number of columns you operate, is to do that by splitting when you split colonies and put in a new queen, that really does reduce mite loads over the season.

    Nicole: 13:15

    So as far as ways to improve our colony health, I know that there's a lot of debate about going into winter and things like insulating them and you know, you mentioned that the colony moves and has to warm the honey. So is it beneficial to insulate our hives, does that help their health or disease prevention?

    Dr. vanEnglesdorp: 13:35

    So yeah, the idea of insulating your hives it depends really where you are. I mean, I grew up and was trained in Canada, right? You would not think about not insulating your hives in most of the places I kept bees when I was in Canada. In Maryland, we don't insulate our hives, there's just no need. And so it really depends on where you are. I think that having like inner covers is a good thing. I think really what you want to do is make sure it's clean feed that is taking your colonies through the winter. Like that's generally true for everybody, that you also want to make sure it's well ventilated. So if you are insulating your colonies, you probably want to make sure that there's an upper entrance engaged. And that upper entrance engagement is in the same direction as your your bottom entrance. So it doesn't cause a chimney effect that wind doesn't blow through the hive. But that upper entrance also allows for the ventilation of a lot of humidity. And remember, these bees are eating honey, and they're respiring, which means they produce water. And so that water vapor needs to be able to escape the colony.

    Nicole: 14:39

    That yeah, that absolutely makes sense. I know that I see a lot of posts on social media, and these are people that say, "Hey, I treated my hives and I still lost them and it looks like I lost them to mites". So do you think that people make mistakes when it comes to treating typically or do you think they're just treating prophylactically without checking the mite loads?

    Dr. vanEnglesdorp: 15:00

    That's a very astute question. And I actually have to say that we have about three or four different ways we're trying to answer that question because I think it's not a straight forward thing going on. So I think that in some cases, and we have very good evidence of this, that there are people who find that the mites go above threshold, they treat and then they check a month later and mite levels are down exactly as they expect. For some cases, then they might stay low as you project. But it's surprisingly often how many times we see people see their mite levels go up, that it drops down after treatment, and then one month later, it goes up again, well past where it was even two months before you treat it. And so what we think is happening there is mites are coming in from the greater environment. And so we learned all of this from the Sentinel, apiary program which is in the Bee Informed Partnership and that program is where you sign up, and you have to actually pay the cost of this. There's some subsidies, but you you get a kit and every month, you monitor. If the same four or eight colonies and you send those bees back to us, we do the processing, we give you a result back. And so when we do that, we find that there's a group of beekeepers who don't treat and their mite levels go through the roof in one season. Then there's a group of beekeepers who do treat some of them are successful and the mite levels say low after treatment. But some see the mite levels go straight through the roof. And so this is this invasion. And so the take home is you need to keep monitoring, even after you've treated. The other problem is is that some of these products aren't working with the same efficacy as they once did. And that's really tricky because some products seem to work well in the spring and then not in the fall or the other way around. And we're trying to tease all of that out right now. We think that that may have some inherent resistance in the bees or in the mites so it's really important that you check your mites regularly, even after you've treated to make sure there's not an invasion. I will say here, we are surrounded, we run about 120 to 100, or 200 colonies at the University of Maryland. And we are surrounded by a lot of beekeepers, small scale beekeepers. Between July and October last year, we needed to go out and treat five times because of the invasion pressure for mites in the area. We would treat the mites would go down, we were happy. And then a week later, they went through the roof again. And that's because there's so many beekeepers, and as those hives die, somehow those might seem to be making it into the colonies.

    Nicole: 17:34

    So for those who would like to maybe get some more information, what sort of resources do you recommend for beekeepers to not only for mite treatments, but just you know, general beekeeping health.

    Dr. vanEnglesdorp: 17:46

    So I guess it's just mite treating the Honeybee Health Coalition came out with a great guide and you should download that. I think that one of the things we tried to do at the Bee Informed Partnership is we have an interactive web page where you can hit the state you're in, and then you can look at the results of all the surveys we've done in that state. So you can see, for instance, okay people in your state, what they treated with and what their outcomes were. So you can see if people my state if they treated with this product, then they lost on average, this number of colonies. And so that's a way you can sort of explore sort of what things work. It's not just treatments there, there's feeding, there's queen type, there's a whole bunch of over 70 different management practices that we asked about in our survey, most of those are being represented so that you can find the important information for your state because beekeeping is very, very local. So that's a good place. We also have the Sentinel Apiary reports there where you can go and look at your state and you can track how fast mite populations grow and change over the course of the year in your state based on all our historical data. So that's a really good sort of advanced if you're really interested in interactive learning. The best thing that any beekeeper can do is find a mentor and the best place to find a mentor, of course, is at your local bee club.

    Nicole: 19:03

    Absolutely. I think that learn from other people's mistakes. And having a mentor is definitely useful. I know I've participated in the surveys and used a lot of those resources and they're really, really helpful.

    Dr. vanEnglesdorp: 19:17

    Good. That's good to hear.

    Nicole: 19:18

    Those are great.

    Dr. vanEnglesdorp: 19:19

    I do want to say that beekeeping is one of the best things to do. I think everyone owes it to themselves to have that experience. And once stung, you know, you're going to be a beekeeper, like, if you're going to be beekeeper once you're stung, it's in your blood. And you know, you're going to do this. But I think it's easy for us, and it's very tempting for us not to be responsible beekeepers. And so I think that it's really important I get that there is this idea, "Well, I'm a backyard beekeeper. If all five of my colonies die. It doesn't matter to me". But I think beekeeping is not an isolated event. You're beekeeping practices are going to affect your neighbor's bees, we have evidence that when a colony is collapsing, we've painted every bee in a colony blue, because we knew it was dying. And we came back three days later, and we found blue bees in every apriary but one within three kilometers of that dying colony.

    Nicole: 20:20


    Dr. vanEnglesdorp: 20:20

    And so you're part of a community, and what you do is going to affect your neighbor. And so it's important that you control your mites, and that you control your disease. It's very tempting to say, "Oh, yeah, I'm just going to let nature take its course I'll let the colonies die that need to die. And I'll breed from the survivors". And I get that that is a great way of making impact and thinking, "Yeah, I can save the world", and who doesn't want to save the world. You know, if you have that colony that survives, you can breed from it and give it to all your neighbors, and that's great. Unfortunately, it's not that simple. Because as those colonies are dying, we have growing evidence that they're killing the neighbor colonies and some of those colonies might be resistant. So if you're really interested in breeding a resistant line of bees, which is, of course, the long term goal of any Varroa strategy, then what you should do is be monitoring mites, and those colonies that consistently have lower mites breed from those, but you can't get away with not treating, you still need to treat for the mites.

    Nicole: 21:18

    I really appreciate your insight on that. Because I know as I've said in other episodes, and on my website, I started out as treatment free because I wanted to be one of those people that you know, let nature take its course and it in your mind, you know, makes sense like that. But it's important, I think to realize that the research shows that that's not the case. And in talking to Randy Oliver, he also mentioned that you know, it's painful, miserable death to let your bees just die of mites. So not only for your community, but if you actually care about your bees, it's really important to control your mite levels.

    Dr. vanEnglesdorp: 21:53

    You're absolutely right and also remembering that we're making it artificial by putting all the bees in an apiary. That's not what happens in nature. In nature, bees stay apart by about three kilometers. So they don't spread diseases quickly. We are keeping bees in an artificial way, and we can't think that the rules that govern nature are always going to apply in those artificial settings.

    Nicole: 22:14

    Yeah, I think that's a good takeaway as well. Well, on that note,

    Unknown Speaker 22:20

    And bees are so much fun and enjoyable. And I talk about them dying all the time, which is a little depressing. But they are fascinating. And I hope that the listeners know that, like, I mean, talk about amazing things and this evolutionary dance they did with flowering plants. I mean, it's an incredible system. And I hope that that positive and fun element comes through even though we're talking about depressing stuff, of course.

    Nicole: 22:41

    No bees, bees are amazing, but I think it's important to understand all aspects of beekeeping to really make yourself a successful beekeeper.

    Dr. vanEnglesdorp: 22:49

    You're absolutely right.

    Nicole: 22:50

    So sometimes we got to talk about the crummy stuff. Yeah. Well, Dr. vanEnglesdorp I really appreciate your time and this I think, has been a really insightful episode and hopefully one that can encourage new beekeepers or current beekeepers to kind of look at the research and incorporate some of these things into their apiary to make them healthy and to help the colonies around them. So thank you so much for your time.

    Dr. vanEnglesdorp: 23:13

    And thank you, thank you very much for what you do.

    Nicole: 23:15

    Thank you. And for those of you listening, thank you so much for joining us and we'll see you again next week.

    Sentinel Apiary Program: 23:23

    Are you concerned about the current state of your honeybees and manage four or more colonies? Bee Informed Partnership is a nonprofit organization dedicated to working with beekeepers to improve colony health and increase colony survivorship. One of the ways we accomplish this is through our Sentinel Apiary Citizen science program. Beekeepers enrolled in the Sentinel Apiary program perform monthly health inspections of each participating colony. In addition samples of bees are taken and sent to our lab to be processed for Varroa and nasima. Beekeepers will receive a report of the results within two weeks so they can make timely management decisions. The Sentinal Apiary Program is a great colony health monitoring tool, and provides Bee Informed with critical research. To learn more about the program or to join, please visit our website at forward slash Sentinel. Happy beekeeping.

    Announcer: 24:24

    Thank you for listening to Backyard Bounty, a podcast by Don't forget to subscribe and leave us a review. If you have a question you'd like us to answer on the show. please email us at [email protected]. Also find us on Instagram, Facebook, and YouTube at Heritage Acres Market. All the links mentioned in this podcast will be included in the description. See you again next week!

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