Think Out Loud

Oregon State University leads study of disease threatening honeybees

By Sheraz Sadiq (OPB)
Dec. 4, 2023 5:40 p.m.

Broadcast: Monday, Dec. 4

A colony of bees Wednesday, June 21, 2023, in College Park, Md. A recent survey says America's honeybee hives just staggered through the second highest death rate on record.

A colony of bees Wednesday, June 21, 2023, in College Park, Md. A recent survey says America's honeybee hives just staggered through the second highest death rate on record.

Julio Cortez / AP


A team of scientists at Oregon State University has recently received more than $4 million from the U.S. Department of Agriculture to lead a study to understand a disease threatening honeybees. The bacterial disease targets the larvae within a honeybee colony, killing them within a few days before they can emerge from their cocoons as adults. Although the disease is not new, it appears to have gotten worse in the past five years, according to Andony Melathopoulos, an associate professor in the Department of Horticulture at OSU, and the co-principal investigator of the study. The disease is of particular concern to beekeepers who travel across the country with their colonies and have noticed a rise in infections following the start of blueberry pollination in April. Melathopoulos joins us to talk about the details of the study, which will also include steps beekeepers may be able to take to protect their colonies and the multibillion-dollar industry that depends on their services.

Note: The following transcript was created by a computer and edited by a volunteer.

Dave Miller: This is Think Out Loud on OPB. I’m Dave Miller. A team of scientists at Oregon State University was recently awarded a $4 million federal grant. They will lead a study into a disease that’s threatening honey bees. It’s called foulbrood. It targets the larvae within a honey bee colony, killing them within a few days. The disease isn’t new but it appears to be getting worse. Andony Melathopoulos joins us to talk about this. He is an associate professor in the Department of Horticulture at OSU and the co-principal investigator of this study. Welcome back to the show.

Andony Melathopoulos: Thanks, Dave. So great to be here.

Miller: What is foulbrood disease?

Melathopoulos: Foulbrood disease is a disease of honey bees that goes all the way back. It’s likely been associated with honey bees for as long back as honey bees have been honey bees. But in 1912, a USDA scientist found out that there were multiple kinds of…they call them foulbroods, and one was designated American foulbrood, the other European. And this European foulbrood is the one that we’re really concerned about today.

Miller: Why is that?

Melathopoulos: You know, it has always been around. I remember when I was a young researcher, seeing it come into a colony and it kind of comes and goes and it was a problem, but not such a big problem. And maybe about five or 10 years ago, throughout the Pacific Northwest and Michigan and Canada, researchers started to notice that this disease was not going away. It would hang around for quite a bit longer than what we were used to in the past. And it would kill a lot of the honey bee larva and the colony wouldn’t really recover after that.

Miller: How does a beekeeper initially know there’s a problem?

Melathopoulos: You can see it. First of all, it’s called foulbrood for a reason. It’s a stinky rotting honey bee larva. So you know it’s there. It also has a kind of distinctive look. A lot of the things that kill honey bees, there’s all sorts of bacteria and fungi, but this one in particular kills it just as it’s going from laying in a ‘C’ shape, as a honey bee larvae starts off, to laying flat on the cell before she spins a cocoon. And so it dies in a kind of corkscrew look in the cell. It’s really distinctive, beekeepers, when they see it, they know it. So as time has progressed, the beekeepers are seeing a lot more of this in their colonies, specifically in the springtime.

Miller: And just to be clear, foulbrood is different from Colony Collapse Disorder, something that we started hearing a lot about in the early 2000′s.

Melathopoulos: It is. Colony Collapse Disorder is, in some ways, where people don’t see the symptoms of it where a lot of the adult bees take off, and they leave the developing bees untended. And people don’t see that symptom anymore, but we still have other problems and this one has really replaced it as one of the problems that beekeepers are really worried about.

Miller: I just want to make sure, I mean, that does seem like good news. So you’re saying Colony Collapse Disorder is not happening now to the extent that it was, say, in 2005 or 2015?

Melathopoulos: Yes. Let the word go out. Colony Collapse Disorder fortunately is something in the past, but there’s always new problems and this one has proven to be really stubborn.

Miller: And worsening, it seems.

Melathopoulos: Yeah.

Miller: What are the big questions that you hope to answer with this new Federal grant?

Melathopoulos: This disease seems to always be in colonies. You can detect it at low levels throughout the year. The thing we don’t know is what caused it to simmer over and ignite into a disease that takes a colony down. And it is a complicated set of problems.

One might think, oh, it’s just the conditions that the colonies are going through. But the beekeepers have really identified some areas where the problem gets worse. But it’s also coupled with new research that shows that there are new strains of the bacteria. And we have this fuzzy idea of these new strains that are sort of marching in, but we don’t have a real inventory of them nor do we understand the function of these different strains.

And on top of it, there’s this - you ask a beekeeper about it and you go to the traditional literature, they say this disease is associated with nutrition. And there’s this question of, is that ignition point that the bees aren’t eating right? Is there a kind of nutritional dimension to it? There’s a whole lot of pieces. There’s a lot of ideas of why this disease suddenly erupts. But nobody seems to really have a kind of concrete way [to] predict it. Some years we have terrible outbreaks of this. A couple of years ago, beekeepers got really hammered and some years it’s light.

So trying to figure out how this disease actually is spreading in the colony, what causes it to erupt into an epidemic. And what points in this disease cycle can we intervene, and maybe keep these peaks from happening? That’s the focus of this research.

Miller: Why do you think there are so many questions still, given that this has been, as you said, most likely in honey bee colonies seemingly forever, and that humans have been aware of it for centuries?


Melathopoulos: I’ve been working with honey bee diseases since the 1990′s. This has been the one that nobody can figure out. Some of the other honey bee diseases, there’s some complications with them, but they don’t nearly have the multidimensional aspect of this disease. And I think one of the reasons is that this disease has such a touch point to the environment, to the way that the colonies are being managed. It really has triggers that we don’t understand. And the real focus of this research is to finally, for the first time in 100 years, really pull back the veil and see what’s causing this disease and what drives it.

Miller: What are the different phases of this study?

Melathopoulos: Well, the first phase is very ambitious. It’s a longitudinal survey. Longitudinal means “over time.” We’re gonna go…we have partners at Washington State University, Mississippi State University and at UC Davis, and we’re gonna track 1,000 commercial bee colonies through two years. We’re gonna track them across time, and at each of those time points we’re gonna look for, where is that disease hiding? Where is it spiking up, what is the consequence to the beekeeper of having this disease? And really try to figure out, where is this disease simmering? And find out where it’s hiding and where it ramps up so that we can really pinpoint how to work with this disease.

Miller: Let’s say that it does crop up, whether in this study or just in general. Are there effective treatments for it?

Melathopoulos: Yeah, that’s another part of this project. Right now, it’s a little bit of a shot in the dark. Beekeepers largely have been using antibiotics on prescription and they don’t want to use antibiotics. They’d rather not put that into their colonies.

Miller: How do you give bees antibiotics?

Melathopoulos: Oh, you just, one by one, they line up and you give them a little tablet. [Laughter]

No, you have to feed it...

Miller: You had me for like a quarter second. [Laughter]

Melathopoulos: Roll up your sleeve there, buddy!

No, no, you can put it in syrup into the colony and that spreads it to all the bees and they feed it to the larva where the disease is erupting. And the larva have a little bit of a dose inside their bodies that theoretically prevent the disease from spreading. But beekeepers have been doing this and still have problems. So either the timing is off or it’s really not effective.

And so part of this work, we have a really good microbiologist, Maude David, who’s gonna be looking at micro probiotics, these little microorganism supplements. This bacteria is in the gut of the honey bee larva. And the idea is, what if you stock that larva with bacteria that are really good…all of us have these microorganisms in our gut. What if we stack the deck? Could we displace this bad bacteria from taking hold? So there’s a large project looking at the microorganisms in the bee’s guts, trying to characterize how this bacteria may take hold of it and hijack the gut and take it over.

We’ll be looking at that aspect, but also there’s some other beekeepers who have all sorts of ideas of where the disease is residing in the colony and where we could snip that away and maybe cut the disease cycle.

Miller: What agricultural sectors are most affected right now by foulbrood?

Melathopoulos: A lot of them are. There’re two points to this answer. Our beekeepers in the state of Oregon, they dip out of the state briefly in January, February to pollinate California almonds. But then they bounce around, they’re doing pears in Medford and Hood River, cherries in The Dalles, they’ll be doing all of the blueberries and cane berries in the Willamette Valley, Hermiston melons, the South coast cranberries.

All of these crops depend on this pool of honey bee colonies. What beekeepers have been reporting is that as they come from California into blueberries in the spring, the disease erupts. And so beekeepers have colonies that are really debilitated and have a hard time doing the subsequent pollinations that we need here in the Willamette Valley. And the repercussions could be much more than what we see on the surface. Tim Delbridge is an economist on our team and he will be going through, trying to figure out what the overall costs are - not only to the beekeepers, but to our agricultural sectors - and kind of working out the economics of this disease.

Miller: You know, I’m just imagining these bees being trucked all over the Northwest or down into California. Does that mean that there’s no way to quarantine bees, that basically you just have to assume that whatever bacteria is somewhere on the West coast, there’s a good chance it’s going to get everywhere?

Melathopoulos: That’s a great question, Dave, and one of the cool aspects of this project is we have a really amazing molecular biologist, Dr Jeff Chang. People have looked at the DNA of this bacteria in the past, but he’s going to be doing whole genome sequencing, taking the entire DNA of all these samples that we pull out from these commercial beekeepers, these thousand colonies, and answering just that question. What is the linkage between these bacteria? Are they related? Is it one homogeneous pool, or is it kind of these little pockets of really virulent bacteria? If we knew that, then we could give the beekeepers much better information and forecasting. You’re in an area where there seems to be a highly virulent strain and you can take action accordingly.

Miller: The timing here seems to be important. If this is getting worse and it’s really affecting some colonies and some beekeepers, I imagine they’d like to get better management practices quickly. How quickly can you turn basic science into industrywide recommendations?

Melathopoulos: It can be challenging and what’s really wonderful is, this project is being led by Dr. Ramesh Sagili and there’s a whole bunch of others in California and Washington - the top apiculture programs. What’s great about these programs is that they work really closely with the beekeeping industry and they’ve had a great track record of solving problems in a timely way.

My sense is that we’ll come out of the first two years of following these colonies, and we’ll really be able to see where these pinch points are. And in the third year, we’ll have experiments testing some different treatments at those points. I am an optimistic person, and I think as the grant comes down, we’re gonna have some real solid recommendations for beekeepers.

Miller: Andony, thanks very much.

Melathopoulos: Thank you.

Miller: Andony Melathopoulos is an associate professor in the Department of Horticulture at Oregon State University.

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