Special Episode: Dr. Emily Monosson & Blight

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Hi, I'm Erin Welsh, and this is this podcast will kill you. I am so excited to welcome you all to another episode in our TPWKY book club series this season, where we interview authors about their wonderful books in science and medicine.

The effects these books have on us or the inspiration we draw from them can be as varied as the topics of the books themselves. With the books just this season, I've been on the edge of my seat, reading as fast as I can to find out what happens next in a book about an element essential to all of life. I've been absolutely raging over a story of misogyny in academia, my jaw fully dropped.

I've been delighted to learn about the regenerative power of the endometrium, and I've been moved in so many other ways by the incredible things I've learned from these authors. If you'd like to check out the books that we've covered so far in this book club, head to our website, this podcast will kill you.com, where you can find pages for each of our released book club episodes.

And if you, like me, were one of those nerds always going past your signed reading in middle school and you want to sneak peek at the rest of the books for this season, you can also find that through our website under the extras tab by clicking on a link to our bookshop.org affiliate account, which will take you to a list of lists, including a book club list, which features all of the books from this season and the one before.

But now, let's turn back to the present, and the book we'll be chatting about today. Blight, fungi and the coming pandemic, by author and environmental toxicologist Dr. Emily Monison. Here at TPWKY, we love talking about fungi.

even if we don't do it maybe as often as we should. We've covered Kitrid fungus, which affects amphibians, white nose syndrome, which has devastated some bat populations, as well as a couple of fungal diseases of public health relevance, coccidioidomycosis and blastomycosis, which was one of my favorite topics to research last season because I got to talk about dinosaurs. Go check it out if you haven't already.

This handful of fungal pathogens represents only a teeny, tiny proportion of fungi that can be pathogenic to humans or animals. And that group itself is minuscule compared to the mind-boggling, beautiful diversity of fungal species that place so many crucial roles in ecosystems and make life possible.

fungi truly are amazing, and all fungal species are certainly worthy of appreciation and attention, but today we're setting our sights on the select few that have the power to do us and plants and other animals harm, especially harm on what is an almost incomprehensible scale.

Allow me to take a quick trip down memory lane to explain in part why I love this book Blight so very much.

When I was an undergrad at the University of Kentucky, I spent many weekends escaping the horrendous traffic on Nicholasville Road on football game days, my teeny apartment with the bright orange walls, and of course, the homework and studying that I probably should have been doing. And I would head down to Red River Gorge for some hiking and camping. It's an amazing place, and you should absolutely go if you get the chance.

But sometimes, while I was driving through the park to get to a trailhead, I would stop at the visitor center, initially for the opportunity to use a nice clean bathroom rather than the pit toilet at camp. Once I had luxuriated and washing my hands with soap and warm water, I would wander around the displays at the center, peeping at the photos showcasing its history, the respectively-done taxidermy of local fauna,

and what quickly became my favorite attraction and my reason for future pit stops at the center. A massive cross-section of a tree, whose label read something to the effect of, this cross-section is of an American chestnut tree. The tree was 180-something years old when it was killed, along with millions of other chestnut trees, by the chestnut blight fungus in the early 20th century.

Next to this cross-section was a grainy black and white photo showing a forest of living chestnut trees whose colossal size was made very clear by the tiny humans standing in their shade. My mind was blown.

I could not fathom, even with the help of more old photographs, the sheer size of these forests, how the forests that I walked in today were so dramatically different than those of 100 years before, how it all changed so quickly and all due to a fungus.

That chestnut tree cross-section has never left my mind, and I admit to every month or two Googling historical chestnut forests out of this morbid fascination, the story of the chestnut blight is only one of many told in Emily Monison's captivating book.

blight, which delves into the history of fungal epidemics and pandemics and asks what these fungal pathogens may have in store for us in the future, as our climate changes, as global movement and travel increases, and as these notoriously hard to eliminate species, see the chestnut blight fungus, establish strongholds in our hospitals and across the world. So let's take a quick break and then get into it.

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Dr. Madison, thank you so very much for joining me today. Your book, Blight, fungi and the coming pandemic was such a fascinating read. And I loved learning more about this world of infectious disease that we, you know, we on the podcast, but also we as the general public don't really give enough attention to. And I'm super excited to dig into some of these fungal pathogens and the patterns that we've been seeing lately.

But first, can you tell me where the idea for this book first came about? Sure. And first, I just want to say thank you for having me and I love your show. So I'm excited to be here. Thank you. So this is something that

kind of was running in the back of my mind for a long time. So many years ago, my first kind of experience with a fungus-like pathogen was a thing called late blight in tomatoes. So if people grow tomatoes, I think they probably know about late blight, especially if they're on the east coast. And that is an organism that I think there was sort of an outbreak of it in around 2006 or seven or something like that.

And it was a disease where growing tomatoes, they looked beautiful, end of the summer, and all the sums, something just came and hit them. And within a day, the tomatoes and their leaves just were dead, hanging on the stock, looking really pretty ugly. And what it turned out was that that was a disease called Pause by an organism called phytophthora infestins.

and it was new to the east coast for tomatoes and it turns out that that disease was probably distributed by a big box distributor who was growing tomatoes starts down in I think Florida and then shipping them up the east coast

and infected the whole least coast. And we have had phytophthora infestants infections pretty much every year, or maybe every other year ever since then, because once it, you know, so what I learned from that was just that I was writing, and I was trying to understand the disease, and what I learned was that it's caused by phytophthora infestants. Same organism that caused or contributed to the great famine in Ireland, the potato blights, same organism.

Um, that it could be spread so easily through buying plants and being distributed up the coast. And that once it gets got established, it's very hard to get rid of, if not impossible. So that was sort of an introduction to a sort of new disease that just kind of came in, you know, cause havoc and.

Like I said, it's not a fungus, but it behaves like a fungus. I think when it was first discovered, they probably thought it was a fungus. It's really something called a water mold.

Then around that time, there was a paper that came out in a scientific publication. I grew up as scientists who were across different disciplines about the emerging fungal threats across species. And so what they were saying was, hey, hey, people, you need to take, you know, be aware and actually included phytophthora infestins because it's fungus-like in this paper. But they were talking about frogs and bats and humans and crops and that, you know, there are fungal pathogens across all of these

species, and they weren't getting a whole lot of attention. So together, that seemed like a really good topic for a book. I had just finished a book about how all sorts of things were getting resistant to all the chemicals we used to kill them.

which was a pretty depressing book. And then this would have been a pretty depressing book. And I was talking with the editor and I was like, this is kind of depressing. And she agreed. And so I wrote a different book that was kind of hopefully more hopeful. So I put this off. And then I didn't really think about it. And then in, what was it? Whenever

fairly recently, Candida Orris. So the yeast fungus that's been infecting people started infecting people and it became a problem and the CDC started putting out alerts. I think that was 2016 maybe. So when that came about, that was sort of seemed like, okay, maybe it's time to revisit and write a book about emergent fungal pathogens.

of which there are many and not just in sort of these big devastating epidemics that we have come across the news like in amphibians or in frogs or in bats, but also as you mentioned in humans. And so what are some of the unusual patterns that we've been seeing lately in this rise in these human fungal infections that have been observed over the past few decades?

So I think the biggest one, I remember speaking to an infectious disease doctor who specialized in fungal pathogens. And he said, he got his degree in the 80s. And he said, if somebody were to come to rounds with a hard to treat fungal problem, that would have been news. That would have been a big deal. And then came HIV, human immunodeficiency virus.

And people started becoming immunocompromised because of it. And fungal diseases started to rise. So that was one of the things, because a lot of fungal pathogens, so I should say first of all, that there are a lot of fungi in the world. Most of them are beneficial. Some of them don't do anything. And only a very small proportion of them cause problems. So that's important to keep in mind.

that we really rely on fungus for a lot of things. In most fungi, we're not really the target for a lot of fungal pathogens, so there are very few compared to viruses and bacteria. They're a small proportion of those kind of pathogenic problems. It would have been unusual

And one of the reasons is we have a pretty robust immune system. And when we do have a robust immune system, we can, you know, we're breathing in fungal spores all the time. And most of us, it's not, you know, for most of us, it's not a problem. So when people are immunocompromised, then fungi are opportunistic.

and they take advantage and they can start to infect you. So back in the 80s, there was a rise. There's also been, there was some commentary that I came across that in the 50s when we started using antibiotics on a large scale. So that there was a quote somewhere where, you know, they fun fungal pathogens were kind of a disease of the antibiotic age and

the thinking there is in part because of our microbiome. Although back then they didn't really talk about that in those terms because I don't think we, you know, nobody really realized how much of a part of us our microbiome is. But so we have, you know, fungi and bacteria that keep other fungi and bacteria in check. So once we start using antibiotics, you wipe out the bacteria, they're not keeping the fungi in check.

And we've been seeing some unusual cases in terms of like person-to-person spread or outside of hospitals or outside of people who have immunocompromised of some kind. Is it sort of a mix of all of these things where we have overuse or potential overuse of antibiotics? We have higher rates or higher detection of immunocompromised. And is it just that we're better at finding and isolating and treating? Well, maybe not treating, but finding and isolating or detecting fungal infections

period.

And it's not just the other thing is there's antibiotics, there's immunocompromised, and there's a lot more tissue transplants. So just a lot of good medical advances have also contributed to this because if you get tissue transplant or an organ transplant, then you can be on immunosuppressants to prevent rejection, that sort of thing. So we have a large population of people that are also transplant recipients and things like that. So there's a lot of reasons why people can be immunocompromised.

Um, the part about are we detecting, you know, what changed and are we detecting it? So one difference in almost all most fungal pathogens is that when we think about bacteria and viruses, we think about spreading it from one to another, you know, where you sneeze on somebody and you spread your virus, we all know that.

So, fungi don't spread like that usually. There isn't that sort of person-to-person contact. So, that's one thing that was raised sort of red flags with Candida auris. So, when this was the yeast that, you know, emerged somewhere around 2016, at least came to recognition in 2016 as a problem. I think it was 2016. I can't remember the year that the CDC issued their warning. And part of it was because here we had a yeast

And yeast is, you know, it's a fungus. We have Candida albacans. That's a very common yeast that a lot of us, you know, we all have it on us and some of us problems. Some of it's not. Candida Ores is another kind of yeast. And this one was one that had a high mortality rate when it infected people in the hospitals and it seemed to spread person to person. So it could spread around the hospital room and it could spread, you know, they thought maybe health workers were spreading Candida Ores.

It was very hard to clear from the room. So there were a lot of problems with Candida Auris. And the other odd thing about Candida Auris was that it emerged here in the US and in many other places around the world, kind of at the same time.

So in 2016, there were these outbreaks in far-flung places of this kind of new pathogen, which was kind of frightening. And one of the things that the scientists that I spoke to at CDC had said was, we wondered, was it something we just couldn't detect before and now we detected it?

So was it something that was just misdiagnosed? And now we know that it's something different. And so they could go back into the archives. They'd had some programs running where physicians were taking samples of fungi from patients. And it wasn't that case. It wasn't that they were detecting it now and not before. They found a few cases that had been misdiagnosed. But

Most of them were really new cases. So it really was an emergent fungus in that case. So it's a very rare thing to have a new disease like that, just sort of emerge. And this one was so deadly. And it was resistant to a lot of the antifungal medications. And it was hard to clear from a room, although they now have learned better how to sterilize a hospital room afterwards. Let's take a quick break. And when we get back, there's still so much to discuss.

Welcome back, everyone. I've been chatting with Dr. Emily Monison about her book, Blight, fungi, and the coming pandemic. Let's get back into things. I do want to take a moment because I feel like I have to ask, even though I'm sure you get this question a lot since writing this book, to go into the fictional world a bit. Have you ever played The Last of Us or have you watched the show? And if so, any thoughts?

I have not played the game, but I did watch the show because it came out right before the book came out. One thing was, it came out in January 2023. One striking thing was right after that came out, there was so much about fungal pathogens in the news.

And in the end of 2022, the World Health Organization had just made this big announcement of these 19, you know, priority fungal pathogens. And so they were trying to get it out there in the news that, you know, here are some fungi that we want you all to be aware of. And that didn't really make such a splash. There was maybe a couple of weeks of the news that, you know, World Health Organization has these priority fungal pathogens.

Then last of us comes out, you know, fungal pathogens are everywhere. So it was sort of like that show did an amazing thing for awareness of fungal pathogens. The one thing that I just cringed from in the show is only mostly that, you know, they had no concern about spores. So they'd be going in where they're dead zombies and you can see the, you know, my Celia or whatever all over the place and

You know, nobody's worrying about breathing in the stuff. But, you know, so I since read, you know, that they didn't want to put masks on all the stars, which you can imagine why, but

Yep. Yep. Okay. That makes sense. And speaking of masks, I read that you worked on this book a lot or at least wrote a lot of this book and researched for this book during the COVID pandemic. What was that experience like compared to previous books that you've worked on and another two-parter? How did writing about pathogenic fungi during a pandemic shape this book?

Yeah, so for this book, I had this, like the other books I've just sat at home, read a lot of papers, called up some scientists. And so for this one, I'm like, I'm going to do a better book. I'm going to go visit laboratories and I'm going to go see bats and bat caves and frogs and that, you know, so I had this, I was going to travel and be right there with the scientists. And so that's what didn't happen.

I did get to Costa Rica. We went to a banana plantation, which was really cool. And I'm glad I had that experience. But yeah, the rest of it was sitting at home talking science except over Zoom. So that was different. I also felt that a lot of them were kind of more relaxed because they're sitting in their living rooms talking to me. And I think the other thing was once I realized that we were really in a pandemic, I had this book called Blight.

to come to pandemic. I asked my editor, I'm like, do you really think people are going to read this? Maybe I should stop writing it because, you know. And the last thing is that it also, since it's come out, talking about the title, you know, when I was before, when I proposed it and was writing it, there hadn't been a pandemic like this. And so the time, you know, pandemic wasn't such a hot button word, I don't think.

you know, and I chose it because I was trying to say that, you know, some of these fungi are like, they're big outbreaks. They're not just an epidemic here, you know, small outbreaks here in Europe, you know, so you might have thought I'm using the name a word like pandemic, but I wanted people to think about it in a large way. But then we had this global viral pandemic and I'm like, but not like that. So,

Right, right. And I think it's a completely apt term. I think that we tend to maybe, in part because of COVID, think about pandemics as in happening to humans especially, very human-centric ideas of what a pandemic is. And that's not necessarily the case. But anyway, so all that is to say is that I love the title. And I think that it is something that we are a little bit in part

have this human bias where we don't think about fungi as much as we do bacteria and viruses, things that we're more familiar with. And humans represent, of course, only a small proportion of organisms impacted by fungal pathogens. Some frog populations around the world have been absolutely devastated by BD, a Kitrid fungus that we did an episode on years back at this point.

Can you talk about why frogs are so susceptible to this pathogen and what the latest is on this fungal pandemic? And are there any glimmers of hope out there?

Yeah, well, so I only know what I've learned from the scientists, and I spoke to Karen Lips, who is one of the lead scientists, and she sort of experienced this decline. It's a good question about why frogs are so susceptible. So part of it is, is that their skin, you know, caroten on their skin, just like we do, and it's food, or the kitrid. Kitrid's are aquatic.

So that's one thing is that they'll spread their spores into the aquatic ecosystem and then that can spread easily. Move around.

frogs breathe, they're basically breathing through their skin. And so this is a skin pathogen. And so once it infects the skin, it, you know, it will poke through and send out its spores. And when it does that, it's completely ripping apart the frog skin. So you've got this skin that's very important for managing electrolytes coming in and out. And then you've got all these, it's just being shredded by this fungus that's eating the skin and then growing.

and sending out its spores through the skin. And so that is what kills the frogs. They're not, I mean, they are. So obviously it's impacted a lot of different species. So that's another thing is that it's not species specific. It's impacted a lot of different frog species.

There's a very similar fungus, and I do think that BD, I might misspeak, but I think BD can also infect salamanders who have a similar part of their lifestyle. But it's not as problematic in salamanders, but there is another kindred fungus that has become called B-cell.

That doesn't act salamanders and that outbreak for that was in Europe and there's a lot of concern because we have some really biodiversity hotspots here for salamanders and there's a lot of concern that if that be sell enters the US, you know what happened to frogs around the world could happen to the salamanders here.

It's alarming, especially because there is so much global exchange, global movement, global trade of thousands of species of plants and animals. And in your book, you use this great term, conveyor belt of disease. So what role has this conveyor belt of disease played in fungal outbreaks? So just about every fungal pathogen that I wrote about,

was an emerging disease and it was emerging in large part because of trade and travel. So every fungus that became emergent pathogen is because it was brought to a new place and it found something to infect that had never seen it before. And that's how why it became so devastating. Those organisms had no defense.

So the movement of plants and animals and us too. I mean, there are some outbreaks that, you know, what happened to the bats, which the whiteness disease is thought to have been kicked off by cavers, bats living caves. That's a pathogen that has killed bats across in the East and is moving across the country. And it was discovered also that that pathogen

does infect bats in Europe, but it doesn't kill them. And it's in the caves in Europe. And so it's believed that people tramping around those caves then came here, tramped around in caves here, left some spores, disease. So yeah, movement.

movement. I mean, it's a real driver of the spread of pathogens. And fungi, especially because like you've talked about, the vast majority of the fungi that we encounter are, or the pathogenic fungi that we encounter are stable in the environment. And so they're or long lived in the environment. And they're

They stay somewhere for a very long time. They're very sticky in terms of not being able to get rid of them. And that's, I think, one thing that makes them so, I don't want to say scary, but kind of alarming in that sense of like, once it's here, it's here. But the other thing that I find really both fascinating and terrifying about some fungal pathogens of humans, especially going back to the humans,

is that some of them can be incredibly deadly even with treatment. And I know that our treatments are somewhat limited in what they can do, but why are some of these fungal pathogens so very deadly?

Ooh, that's a good question and I'm not a physician. And I don't really have a good answer for that except that when we're thinking about some of the people who are infected that they're immunocompromised. So that gives the fungus some advantage. I think some fungi are also good at evading the immune response. So there's that.

And I do think part of it is just that some of them are hard to treat because there aren't that many antifungal medications. There are very few classes of antifungal medications. And so once a fungus can overcome all of them, there aren't that many options after that for treatment. So resistance to antifungal medications is a real problem.

Most, if not all, countries have regulations or laws that limit the importation of plants or animals into the countries, in part, to try to prevent pathogens from coming in and affecting these immunologically naive populations. But these laws aren't perfect, and you pointed out one gap with like

humans just not knowing that we're transporting the fungus responsible for white nose syndrome on our boots if we're cavers and we're going from one airport to the next and what a cool cave. Let's pop in that one and then go back home, pop in that one.

So there are some of these gaps that we see, but there also seems to be sometimes resistance to stricter laws or longer quarantine periods. Why is there some resistance? So that's kind of both a big and simplistic question at the same time. Yeah. To why there's resistance? I mean, I think sometimes it's just such a

a big ask in many ways. And then some people would say it's not a very big ask. And I think what I wrote about was sort of, so there were two things. And I have to say right up front, regulation, not my strong point, I find them very complicated to even, you know, to try to dig into the history to understand the current regulations. The biggest gap that I came across and I think that people would point out is that for plants,

since the 1900s, because there were a lot of outbreaks in plant diseases. The USDA, I think it was, there was a big fight between a couple of different factions of people who wanted to bring in plants from all over the world and people who said, no, no, no, those were bringing in pests and pathogens. And so there was a big fight. But in the early part of the 1900s, they actually did eventually come up with some regulations about quarantines. And you couldn't bring soil in. You couldn't do this to protect plants.

So plants, there is some healthy regulations. And we actually have a national mycologist. We have two. So that's a position. And their role is to identify odd things that come in plants that can't be identified. And that might be pathogenic. And so they're sitting there in their labs constantly. And a lot of stuff comes in. They look at a lot of different kinds of mostly fungal spores, because that's how they can identify them.

So we have these people looking out for plants pretty much. And still we get plant pathogens slipping in. OK, we don't have the same thing for animals that are pet trade animals. So for food animals, we do because we're worried about humans and disease and our food. But for other kinds of animals that are in trade, there is not, for a lot of them, there is no, you can't come in with this disease. They're not checked for disease.

Part of it is a capacity thing and part of it is, you know, I can't tell you why not. So now we're talking about millions of animals coming over and crates of animals and things like that, how difficult that is. So that's a big gap and it was almost shocking. I had to ask a lot of times, I'm like, you mean there's no national mycologist equivalent for animals? This seems so important.

And there isn't. So I will say one more thing just about when I mentioned the BD in the salamander. So this is something that's kind of good that came out. I mean, the B-cell in the salamander. So I mentioned that there's concern that this ketrid fungus that's in Europe will come across to the US. And so those scientists that were working with frogs and knew how devastating the disease could be of the ketrid BD could be in frogs.

got together and they first tried to have some new regulations, there's some enforcement about bringing disease frogs into the country and that really didn't go anywhere because the response was, we already have the disease here, so how are we going to stop it?

But when the B cell came along and the salamanders, they got together again and they said, hey, it's not here. Maybe we can stop it. And what happened, and they worked with, it was non-profits and federal agencies and academics all working together to do this. And what they did come up with was in the end a list of, I think, 200, maybe nine or something salamanders that cannot

coming into the country because they are known carriers of BSL. So it's not exactly what they wanted, which would have been, you know, you just can't bring the FB tested for disease or get a health certificate that says you have no disease. But it's a step. And so in so far, we haven't had BSL here. There is monitoring for it. But so that's kind of worked. But that's really, you know, when you ask about regulations, how you do things. And, you know, that took a lot of effort.

On this podcast, we're mostly talking about animal diseases and animal immune systems. But as you discuss in Blight, plants, especially trees, are incredibly impacted by fungal infections. How do tree immune systems work? And why are they so susceptible to some fungi? So trees have

They do multiple things so they grow. They have, you know, when you look at bark, that's like our skin first line, but they also do this thing where they grow, you know, in layers, right? So when you sometimes see the inside of a tree that's looks kind of, there's nothing there. It's, it's dead. And so they grow and they can wall off.

pathogens, it's just the way they grow. And so that's one defense is that if something gets infected, they can kind of just grow around it, wall it off, and don't need that part. They don't need a branch or like we need our arms. So that's one thing. But the other thing, they do produce a lot of chemicals. I mean, we know this in plants, right? Because we either use a lot of plant chemicals for drugs or whatever. And a lot of these sort of secondary chemicals that they're producing, including things like alkaloids,

that might make foods bitter are defenses against pathogens. So that's another thing that they'll do is they can produce different kinds of chemical products to fend off disease and in pests too, insect pests.

when that doesn't go according to plan, it can be incredibly dramatic and awful. So one of the most tragic stories of a fungal epidemic is chestnut blight. And it's just so hard to wrap my head around how different some North American forest looked like before this epidemic struck. So can you take us through this tragedy? How was first recognized and then what led to this

dramatic and rapid change.

Yeah, so chestnut trees, the American, because a lot of people around me are like, well, but I just got some chestnuts. I'm like, yeah, but they're not American chestnuts. If you got them from the farmer down the road, they're probably some hybrid. So American chestnuts were huge trees, beautiful trees, very productive. They ranged along sort of the Appalachian range and up along the East Coast. They were really important trees in many ways, both to humans and ecosystems.

And so the story of the demise of the American chestnut kind of begins at the Bronx Zoo. So when they were first developing the zoo, the society that wanted to bring these, you know, have these exotic animals on show and everything.

They were also very interested in the trees on their property. So they had a lot of acreage and they had a lot of old trees. And so they thought that those trees were just as important almost as the animals that they were going to bring in. And so they hired a forester.

He was in charge of the trees and it was his job to make sure that all the trees in the park were good, healthy, whatever, and plant other stuff in the park. And so he knew all the trees in that park and there were something like over a thousand chestnut trees and some of them were the big old beautiful chestnuts. And so I think it was in 1904 that Merkel noticed on a couple

chestnut trees, some of the leaves were kind of curling and look like they kind of look like it was fall. They were sort of dying at a time when they shouldn't have been. And so he thought, well, this seems like some kind of disease and he could see some little spots on the trees and he thought, you know, maybe it's a fungal disease, but just a few trees, maybe won't come back next year. So you didn't worry about it.

1905 almost every tree in the park was infected with this fungus and their leaves were curling up and dying. And so he, at that point, got worried called the USDA asked what to do. One of the things that they did at the time, what to treat fungal pathogens, which I thought was interesting because we still use this today's treat them with copper.

So copper is an organic fungicide, and it is effective against fungus, but it's topical. And so the response to him was, well, cut off the dead branches and treat the trees with copper. Well, he had 1,000 big old trees. That wasn't really in early 1900. He tried to do that, but that was not that effective, and it was just overwhelming.

He brought in a colleague from down at the botanical gardens and he identified as something different and he identified as what would become known as chestnut blight. By the time he figured out what it was within that year and identified that it was in fact the organism that's infecting and killing the chestnut trees, he predicted that all the trees would probably be infected and dead within a few years and he was right.

And what happened from there was that the blight spread from New York all the way down through the Appalachians, killing chestnuts, just about every single chestnut tree, millions of trees, maybe billions. Within decades, there were no more American chestnut trees growing. Now, people also cut down the trees in part to maybe make a firebreak of infection, you know, to stop the infection. And also because chestnut wood was so valued and, you know,

They were going to try to stop this and nothing stopped it. One thing we haven't talked about is spores. So, you know, fungi makes spores except for last of us, which didn't have spores, but it could have. And I think maybe in the game it does. I'm told that they actually were mouse in the game. So anyway.

You know, fungi spread by spores. They can put out hundreds of thousands or millions of spores. And in the case of the chestnut of light, you know, these trees would be infected. The fungus is putting out spores. The wind can carry spores and these spores can be carried by birds and insects that, you know, go to the trees and then go to the next tree. And so, you know, it just, it spread rapidly and it was unstoppable.

As that was happening, as they were realizing that they're losing these valuable trees, they wanted to understand something about the fungus. And so they, there were these people called agricultural explorers around 1900s, which was part of that fight. Remember when I said there was the argument about, you know, collecting and bringing in stuff from all over the world, but so wrong with that.

So they had these, and they were dedicated explorers who would do that. They'd go all over the world looking for plants and fruits and crop plants and trees and bring them back. And so they're having to have an explorer that was going to China or he was in China at the time. They got in touch with him and said, hey, there's this fungus on the chestnut tree.

We know there's chestnuts in China. Can you see if this fungus is there? Can you identify this fungus on those trees? And he did. And what he also noticed is that those trees weren't really impacted by the fungus.

He got word back. And so in the end, what people figured is that some of those trees that had been imported from either China or Japan, they're very popular. We have neighbors with Chinese chestnut trees still. That fungus probably came in on some of those imports and then spread throughout the country.

But that understanding that now they know that the Chinese chestnut trees have some kind of resistance against the fungus because it co-evolved with it, right? The two evolved over how many hundreds of thousands of years together. That maybe there might be some way to use the resistance of Chinese chestnut trees and breed it into the American chestnut trees. So that started a whole new program to try to bring back American chestnut trees.

One thing that I haven't mentioned, because we are so human centric, is that each time you do this, you're changing the whole ecosystem. And so you remove a key species like that, where you remove a frog or a bat and it changes things and it's not, you know, it doesn't always have to, sometimes it is still relevant to us that the ecosystem has changed. But, you know, you can just imagine the changes that happen when this occurs and you take a whole species out of a system.

instant huge transformation with unforeseeable consequences. And there are some consequences, I think, that are a bit more easily seen when it comes to agriculture and especially a lack of biodiversity in agricultural practice.

So monoculture, basically. So could you take us through the story of bananas, this fruit that we eat so much of all the time around the world, and maybe we don't ever give a second thought to the banana that we hold in our hands? Yeah. So the banana story, which we did, like I mentioned before, it got to go to Costa Rica, went to this place called Earth University, which is a really cool place. They're growing

Banana sustainably, because it's difficult to grow banana sustainably. For a couple of reasons, one of them is fungus, no matter where you grow.

But the story that I focus on there is a story of a fungus called TR1. It's an oxysporum, some kind of fungus. And so back in the 30s, 40s, and 50s, bananas, big business, they were grown on these huge monocrop plantations in Costa Rica and elsewhere, Honduras.

And they, at that time, there was this fungus that emerged. And it started killing those bananas in the bananas that we ate were called the gross michelle banana. And so they call them dessert bananas. The bananas that we're all eating. So I should also clarify that there are

There are different kinds of bananas. We happen to eat one, as you mentioned, that's grown in a big monocrop, basically clones. They're just clones of each other. They're not even because bananas don't have seeds, so they're really, really clones. A lot of people eat other kinds of bananas. So this particular fungus impacted the banana that we were all eating, the banana that was grown, the gromi shell that was imported.

and it was devastating to those crops. And interestingly, it didn't bother the other kinds of bananas.

But it was the industry that got worried. And so basically at that time, back in the 50s and 60s, there were concerns that they might not have any more bananas because that's a fungus that if you when you talk about scary spores, that's one that makes spores and it can make this kind of spore that some scientists say has been detected in soil. So it's a soil born fungus means that it's in the soil, then it gets up through the banana from the soil.

makes spores, it can last in the soil for 10 years or more, so decades. So this is a kind of thing that once it impacted plantation, got in the soil, you just can't grow bananas there anymore. And so what the industry would do back then, because it was not a great industry, would just be to move to another place and grow their bananas there.

leave behind the other land that they, you know, so they just kept moving, but it became clear that they were going to be out of bananas. And so in around that time, there was a, you know, discovery that there was another kind of banana called the Cavendish that was not susceptible to that fungus. So that was a very, you know, that fungus was very specific for the Gromishell banana. And so they replaced the Gross Michel with Cavendish, which is what we eat.

but they basically did the same thing. So they just planted huge monocrops of banana, same kind, same clone banana everywhere.

wherever bananas are grown for export. I think it was in the 70s, maybe slowly, a new kind of fungus emerged called TR4, so the first one was called TR1, second round TR4, similar kind of fungus causing the same kind of problem, and it is frightening growers.

It was believed to be transport in soil, so that would have been in boots of people or farm machinery that was transported from one place to another. But one of the scientists I spoke to said, you know, even though we know that, I don't think that that's the only way it spreads and that that would really stop, you know, that even if we were totally hygienic about this. But there are, you know, you used to be able to go in Costa Rica,

I think if you went several years ago before TR4 became a problem, you could go take a tour of banana plantation, which is just really fascinating to see how much care.

The bananas that we eat, we don't pay enough for our bananas. Let's just say that they require a lot of care. And so you used to be able to go there and see how they do that and that you're not allowed to do that anymore because there's too much concern about TR4. So we were kind of fortunate to be able to get a tour of the smaller plantation. But yeah, so there's

TR4 is out there and there are concerns about what will be next. And so some of the banana breeders and people who work with bananas have said, yeah, we might lose this banana, but there are a lot of other kinds of bananas. And so one thing to think about is that when we, you know,

When I was growing up, there were a few different kinds of apples, and that was it. And now it's mind-boggling. I think just in the last two years, how many different kinds of apples there are out there? So there's that, that different kinds, if we are open to having some diversity in our banana, that would be great. And another thing is that growing these huge monocrops,

Um, with, you know, so there are other ways that was one of the things that the scientists that I had visited was doing was experimenting with how to grow large crops, but not in these big monocrops to have them in blocks and have other stuff planted, you know, agro, ecology, agro, forestry, whatever have other stuff growing in between other crops growing in between so that the, you know, disease can't spread so easily. So there are ways of, you know, dealing with this and it's just that we, you know, we, we,

Need to change what we want and what we accept and also how we grow things. Diversity, you had mentioned diversity, so I'm glad you said that biodiversity before, because it reminded me that that's one of the most important things for all of this is that we need to understand and do whatever we can to preserve biodiversity across species, no matter what we're talking about.

It's amazing to me that we are provided, you know, learning opportunities all of the time from fungal pathogens, from other types of pathogens, from don't, you know, maybe giant monoculture is not a great idea and that we have to keep relearning those lessons over and over again.

That's a problem. It means we didn't want to learn them. Yeah, exactly. If we're learning them over and over again, we never learned them in the first place. For my last question, I want to go back to the title of your book, Blight, Fungi and the Coming Pandemic.

And I want to ask you not about why we should be wary of fungal pathogens, because I feel like we did a pretty good job covering that so far. But I want to ask about what should give us hope in our ability to detect or control or treat a possible fungal epidemic in the future. So one start is awareness.

So just being aware, when we talk about, you know, you go to the airport and they ask you to not take any plants or plant bits or whatever, pay attention. There's a reason for that. There's hope in new developments, like we talked about better analysis, faster analysis, you know, if you can, you know, diagnosis, if you can have rapid diagnosis, that sorts of thing. There is some hope there.

You know, I would hope that with trade and travel, but trade that we can be more aware of sort of what we want. There are some people that say, well, why do we need to plant, you know, plant plants from other countries? Why don't we just

you know, grow what's native. So that's why not, you know, freely. And similarly, I think there are people who would like to see less animal trade or, and you know, the flip side of that is that some people say, but then when you do get to have a salamander or some kind of odd lizard, you develop an awareness for that animal and a, you know, some kind of you.

want to save that animal. So there is, you know, it goes both ways, this kind of thing. I think that just having some greater awareness grow things in different ways. I think, you know, people in agriculture are beginning to understand and think about how to grow crops differently so that they're not so disease prone.

just diversity in what we eat and what we want. Why do we just want one type of wheat? Maybe we could be eating all sorts of different grains, which we're just starting to do. But that's one way. So there are those kinds of things that we just have to be open to more diversity in what we want. We also have to be aware of protecting the diversity that's out there.

and just more cognizant of how we all live in this one world. Plants, animals, humans, we're all together in this one world and we all impact each other. We're not in our little human bubble.

everything interacts with each other and we really need to take that seriously. And I think if COVID didn't get that us thinking that way, I don't know what will, which is kind of a sad note to end it on because I'm not sure. You know, I do think there's more awareness of ecosystem health, how important that is for diseases and things like that. So we just have such short memories. That's the problem.

You know, this conversation just reinforced how amazing and fascinating fungi are. Dr. Monison, thank you so very much for taking the time to chat with me. We covered so much ground in this convo, but there is still so much more to the world of fungal pathogens that I'm sure you all want to learn about.

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