Museums and the Mafia: The Secret History of Citrus

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It smells like I almost want to say a perfume factory, but I don't like perfume.

Like it's so intensely fragrant.

It is, it's amazing.

I spent a couple days, like almost all day out here, and it was like a little, my nose was like tired at the end of the day from just because you know when it's in the peak of bloom, it's just so intense when you're out in the middle of it.

You know, I was thinking this morning when I was here early how beautiful a day is.

We got like snow-capped mountains, we got blooming citrus.

What else could we ask for?

It is the most magical place on earth.

And it is in California, but it's not Disneyland.

This is the University of California Riverside Citrus Variety Collection.

And as the director Tracy Kahn said, it was unbelievably amazing.

The good news is we're taking you there in this episode on a citrus adventure.

You're listening to Gastropod, the podcast that looks at food through the lens of science and history.

I'm Nicola Twilley.

And I'm Cynthia Graeber.

In this episode, you'll not only stroll through clouds of fragrant orange blossoms and taste mouth-watering pomelos with us, but you'll also learn about what was quite possibly the world's first controlled clinical trial with lemons.

We made today's episode with the help of Givodin, a global leader in the fragrance and flavor industry.

They make a lot of citrus-based flavors, and many of them are inspired by the citrus variety collection at UC Riverside, so they help support the research there.

To mark the 10th anniversary of that relationship and to safeguard the future of this amazing collection, this year Givodin gave a million dollars to endow a new chair there.

And they flew me out to California to join them on a group tour of the Riverside Grove.

Thank you, Givodin, for your support of UC Riverside and for making this episode of Gastropod possible.

At the beginning, there were three kinds of citrus.

When we were walking around the citrus variety collection, Tracy Kahn told me there were four ancestral varieties.

Well, and maybe there were actually five.

It all depends on how you count them.

Helena Attlee wrote a book called The Land Where Lemons Grow, The Story of Italy and Its Citrus Fruit.

And she's referring to the fact that nearly all the most common citrus we eat come from three ancestors, the pomelo, the citron, and the mandarin.

We'll tell you more about each of them in a second.

And Tracy, she said that that fourth ancestor she told you about, Cynthia, that's the pipita, which no one has ever heard of.

And I brought one of them for you to see.

This is what it looks like.

You should smell it, because it smells really distinctive.

They're tiny.

They're tiny.

And most of the pupitas no one ever eats, but the one that you might know if you eat Thai food is called citrus hystrix or kefir or kufer lime.

I don't think I've ever seen a kaffir lime, but I have bought its leaves once.

I was trying to make an authentic Tom Yum soup.

I didn't realize it was a whole different species.

Okay, and for those of you keeping count, that fifth ancestral citrus, that is the kumquat.

And it's actually not a citrus.

It's like a citrus cousin, but it does interbreed with citrus.

A kissing cousin.

Citrus is so perverse.

It is, and that's kind of what's amazing about it, and why we have so many different varieties of citrus.

All these ancestors, and cousins, and relatives, they interbreed with each other all the time, and we end up with the delicious results.

There are more than a thousand different varieties of citrus in the UC Riverside collection.

Two of each type planted in the grove, and two more grown in pots in screened-in greenhouses to keep them safe from disease.

It has the most varieties of any collection in the U.S.

So, the UCR Citrus Variety Collection dates back to 1910.

It was originally part of what was called the Citrus Experiment Station.

And the Citrus Experiment Station was established here because there was a growing citrus community.

And the reason there was a growing citrus community is that Riverside was actually a planned community.

People moved here with the idea of growing things and having businesses here, but they didn't know what they were going to grow.

They tried all different kinds of things, including growing mulberries for silkworms and carob and eucalyptus trees for lumber.

But instead of all of those things, they decided on citrus.

The Spanish missions all up the coast had citrus groves brought from Spain and the trees grew really well in the California climate.

The first commercial citrus farm was planted in what's now downtown LA in the 1840s and immediately there was a huge market because miners were flooding into the state to dig for gold.

Citrus became the second gold rush and Riverside became the focus of that gold rush.

In fact, it was the richest city west of the Mississippi in the late 1800s all because of oranges.

But citrus was still a pretty new crop in California and growers had questions about how to keep their plants healthy and what varieties to grow and all sorts of things.

So they petitioned the U.S.

Department of Agriculture to start a citrus experiment station at Riverside.

And that's how the citrus variety collection got started.

Wandering around the grove now past each pair of flowering trees, it can feel something like walking through a citrus arc.

But the collection is not just an archive.

Right, it's also an amazing resource.

It's the source material for researchers developing new varieties or trying to breed disease resistance.

You know, being out in the collection tasting the different citrus, I didn't go with you this time, Cynthia, but I've been before and it's wild.

It's complete sensory overload.

I just wanted to eat everything.

That is your reaction to everything, Cynthia.

It's true.

The thing that blew me away is, you know, when you go to the store to buy an orange, it's just called an orange.

But when you're in the citrus variety collection, there's no such thing as just an orange.

I mean, there are ones that are early season, like Fukamota or Atwood.

There's mid-season ones, like Washington Naval and Fisher and other ones.

And then there's late season ones like Chislet and Autumn Gold and Powell and many others.

They do have fruits that you could find at the store.

One is called Oro Blanco.

It's a sweet sweet white grapefruit that they helped breed and it's delicious.

They also have new weirder ones they've bred that are not so easy to find.

Okay, this is called Valentine and Valentine actually matures around Valentine's Day.

It's a three-way hybrid, a cross between a blood orange, a mandarin, and a pomelo.

And the one another reason why we called it Valentine is because when you cut it long ways and look at it, it looks like a heart.

Wow, it's beautiful.

It has veins of red like a heart.

When When I visited, we tried something called a bale fruit, which is a strong candidate for the weirdest freaking fruit in the world.

And bale fruit is really important in the Hindu religion.

But you can also take the fruit, which are super hard, like sort of like a baseball in terms of its hardness.

And the only way I can get them open is by standing on them with my weight of my body.

I can squish them.

And then when I open them up,

they have mucilage.

They don't have juice vesicles like

we're used to with oranges and lemons and lime.

They have this goo, this yellow goo,

and it smells quite sweet.

That was one of those eating experiences I filed in the interesting category.

The texture was a challenge, to be honest.

A bit too much like mucus.

That's how Tracy described it to me, too.

Lovely.

But wait, we still haven't introduced you all to the ancestors of these varieties.

There was the citron, which is like an enormous knobbly lemon, which which grew in northern India.

There was the mandarin in China.

And the pomelo, which comes from Malaysia.

So of all of those, the mandarin sounds the most familiar to me, but no.

And it's not the kind of mandarins that you usually think of as mandarins.

It's actually much smaller, seedy,

and a little bit acidic, more acidic.

A pomelo is a huge citrus.

Some get to be almost as big as your head.

It's got a really thick rind.

I happen to pronounce it pomelo.

I grew up saying pomelo, but pomelo, that people say it different ways.

Gastropod listeners will already be used to me pronouncing everything differently, so I'm sure you guys can roll with a little pomelo-pomelo variation.

The final one in our ancestral three is the citron.

It's a strange one.

It's usually bigger than a lemon, but it's usually lemon-colored, and it's almost all peel.

The peel is what we generally use in citrons because it's the peel that gets candied.

Is it as bitter as the peel in an orange?

No, it's very sweet.

Should we cut open?

Tougher to cut through.

Yeah.

It's actually kind of interesting to eat the peel.

Okay, I've never eaten this peel before.

Oh, it's really sweet.

But weirdly, the fruit itself is wildly acidic and people tend not to eat it.

So those three, the mandarin, the citron, and the pomelo, those are the great-grandparents of pretty much all the citrus today, including oranges and lemons and limes.

And all three originated in the same part of the world, roughly, what is now southwestern China, northeastern India, and Malaysia.

And then they did lots of their incestuous interbreeding.

For instance, an orange is a cross between a mandarin and a pomelo back and forth a few different times.

A sweet orange is 5/8 mandarin and 3/8 pomelo.

And just to confuse things, a grapefruit is a cross between a pomelo and a sweet orange, which was already 3/8 pomelo.

And then sour orange crossed with citron generated lemons.

Sour oranges might be unfamiliar to many of you today.

Unless you're a Paddington Bear fan, sour oranges are the key ingredient in his sandwiches.

A sour orange is a less pretty fruit than a sweet orange.

I mean, to eat it is impossible, raw.

It has to be cooked.

And it's what you use for marmalade.

So when you...

bite into a chunk of peel in marmalade and you get that taste which is almost incense-like and that's the taste of a sour orange.

It has an incredibly distinctive, powerful bitterness which is wonderful when it's cooked.

For a long time sour oranges were the oranges.

They were the ones that introduced the rest of the world to citrus.

It was brought by traders either by what, as seedlings, as pips, as fruit, we don't really know, but wherever people settled they grew it.

Sour oranges travelled all along the Silk Road to Baghdad in the ancient Persian Empire and people fell in love with them.

You see them in very very ancient cookery books making a great fuss about extracting the juice from sour oranges, the oranges we used to make marmalade today, and then adding it to meat dishes.

Sour oranges actually play an important role in one of the oldest Persian dishes, this sort of lamb meatball thing that people still make today.

The citron came along the Silk Road with a sour orange too.

We told you listeners that most people don't eat citrons today, and I personally know them because every year Jews celebrate the holiday of Sukkot in the fall with an etrog.

It's a type of citron.

But when you look in the Torah, the Bible, it doesn't specify that you have to use a citron.

It turns out that the ancient Jews discovered this amazing new fruit after they were exiled to what's now Iraq about 2,500 years ago.

As I understand it, as I've been told, it was when the Jews were exiled in Babylon.

And in Leviticus 19, the instructions for preparing for Sukkot are to, among other things, pick the fruit of the most beautiful tree.

And they saw the citron in Babylon, and it's a tree that it's not terribly beautiful in its form, but everything about it is scented.

Its bark is scented, leaves are scented, the fruit is scented, and the flowers are scented.

And so they chose it as the tree, the most beautiful tree.

When the Jews were allowed to go back to Jerusalem, they took the citron trees with them.

And then when the Jews were exiled again, they left for Europe.

And obviously, they brought this gorgeous citron with them, which makes them the first people to introduce Europe to the wonders of citrus.

But Europeans weren't that crazy about it at first.

For a long, long time, if we jump backwards a bit and you read about citrons in ancient classical Greek treaties, they think it's inedible.

And then I I think gradually people

saw Jewish children eating citrons, you know, after the festival was over and things, and they realised you could eat it.

But it appears more as something that you might use as a gigantic mothball in your clothes.

It wasn't really considered something to eat in Europe for a long, long time.

Europeans didn't start eating citrus until hundreds of years later.

That's when a bunch of North Africans showed up in the 9th century with some tastier varieties.

They were Berbers, really, nomadic tribes and farmers from the edge of the desert,

started to look for better farming land.

And they came to Sicily and they came to Spain and also to a little bit to Calabria in southern Italy.

And with them, they brought lots of different crops, including sour oranges and lemons.

There was a lot of work involved in bringing the Sicilian irrigation system up to scratch to grow these precious fruits.

But they were important to the invading Moors and they quickly became important to Europeans too.

Well, in the Middle Ages, sour orange was king, partly because lemons weren't reliably bitter

and people

wanted to know they were going to get that bitterness in their cooking.

So they turned to sour orange to get that dimension of flavour in their food.

And they often combined it with spices because spices were a way of sort of adding prestige to your cooking.

They were very expensive, they were very exotic.

And they were often mixed to a paste with sour orange juice, then put onto meat as a marinade and also sort of put on again during roasting.

Sour orange juice was added again at the end of cooking time.

And so it really was the distinctive taste in cookery at that time.

But while Europeans loved the puckery, sharp flavour of a sour orange, they hadn't even tasted what we think of as an orange today.

It took another few hundred years for sweet oranges to show up.

There's a lot of debate about that, but really not till the late 15th century.

Probably came from China.

Finally, Europe has a full suite of citrus.

Citron, sour and sweet oranges, and even lemons.

And people love them.

Italians in particular.

They use them for all sorts of things.

Oh, yeah.

Certainly there were some traditional games where citrus used to be stuffed and used as a football.

On the more prosaic side, citrus provided a wide variety of treatments for the medicine cabinet.

I seem to remember reading a treatise that suggested that the essential oil of the citron, when applied to the appropriate parts of the body, could act as a contraceptive.

Good luck with that.

And of course, citron was still used in its traditional role as a giant mothball.

A mothball contraceptive two-for-one bargain.

One that smelled absolutely divine and probably didn't work, at least not as a contraceptive.

And citrus didn't stop being promiscuous itself in its new European home.

For example, the citron on the sour orange got it on and produced something called a bergamot.

It happened just by chance in the 18th century on a stretch of coastline in Calabria, which is the southern tip of Italy.

And it looks like an orange, sort of orange-sized, but it has glands, if you like, just under the surface of the skin that are full of essential oil, which makes bergamot the most valuable citrus in existence because that essential oil is needed in the perfume industry.

One of the earliest and most famous modern perfumes, Eau de Cologne, that has bergamot oil as its base.

You might more commonly know bergamot today as the flavor in your earl gray tea.

But all that breeding back and forth, it produced some truly bizarre varieties, and the Italians loved to collect them in special citrus gardens.

The most famous collection was the Medici one in Florence.

Throughout the 16th and 17th century, their citrus collection continued to expand, and tourists flocked to gawp at all the weirdness.

There was an orange that was said to be so sweet that you could bite into it like an apple and eat its peel.

I doubt that would be the case for us, but that's what they thought then.

There was another one which was described as being pregnant and the uterus, slightly disgusting, was split open so you could see all the tiny babies packed inside.

There was another one that looked as if it had babies' fingers coming out of the top of it.

And it's these sort of strange fruits which were called bizariye or bizarre from the 16th century onwards that were the kind of prime objects in a citrus collection and it was because of this and because they were so interesting botanically they were so rare they were so highly prized that citrus collections became part of a much larger intellectual landscape they became part of the collections of curiosities which were the first museums private museums in italy citrus collections as the foundation of modern museums i had no idea one of the citrus oddities that the Medici prize is something you can still find in the store today.

It's called a Buddha's hand and it's the result of an ancient mutation in a citron that caused the sections not to fuse together into a ball but sort of curl outward like fingers.

Yeah, Tracy showed me one on the tour.

And each one's different but this is really very pretty.

But the cool thing is that unlike this citron there's no flesh inside.

It's all peel.

There are entire web pages devoted to what the heck to do with a Buddha's hand, other than simply gaze at its weirdness and wonder like a Renaissance Italian.

People tend to candy the peel or use it in cocktails.

We've now caught you up on the peculiar ancestors and the early history of oranges and lemons and citrons, but we promised you the story of the first controlled clinical trial.

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Some of you may remember that I am a limey, otherwise known as a Brit.

So the thing that makes no sense, really, is that Brits should be named after citrus when it's too damn cold in England to grow limes.

Whether a side Brits should really have been called lemonies, though that's a little harder to say.

The origin of this nickname goes back nearly 300 years.

That's when a Scottish scientist discovered a way to keep British sailors from getting scurvy.

And it took our Royal Navy in Britain a very, very, very long time to accept his findings.

But when they did accept it, they gave Sicily and Malta the contract for supplying lemon juice to the British Royal Navy all over the world.

Scurvy is caused by a lack of vitamin C, so if you eat enough fresh fruits and vegetables, you're usually fine.

But at the time, there was no refrigeration, so sailors on long voyages couldn't bring fruit and vegetables with them.

And they came down with scurvy pretty frequently.

It's a disgusting disease.

You feel weak and tired, you get loose teeth, horrible breath, bruising, swollen limbs.

And then your gums bleed and your teeth fall out.

And then you die.

So obviously, the British Navy wanted to prevent its sailors from succumbing to the horrible scurvy scourge.

And so that brings us to Helena's Scotsman and a controlled therapeutic trial that some people claim is the first in history.

It was the mid-1700s, and James Lynd was a naval doctor.

He took 12 patients who had scurvy.

All of them were in pretty bad state and pairs of them got a variety of treatments.

Some had cider to drink every day, some had sulfuric acid, some had vinegar, others had seawater, and two were given two oranges and a lemon every day.

In his paper describing the experiment, James wrote that the results were clear.

Oranges and lemons were the most effectual remedies for this distemper at sea.

And then the Navy ignored his findings for 40 years.

But then finally they said, yeah, we need lemons.

They got those lemons from Sicily and Malta.

And this made millionaires of the Sicilian lemon farmers.

But then the Brits did something almost as dumb as waiting forty years.

It was patriotic, Cynthia, not dumb.

Or maybe both.

But anyway, they switched citrus.

And so after I think it was barely fifty years, they were using lemons.

And then somebody said, well, it would be much more patriotic to buy lime juice from Bermuda and so we keep the money you know within British territory and so they pulled out of Sicily and Malta and they started to use lime juice.

What they didn't realize was that the vitamin C content of lime juice is very very inferior to lemon juice and so everything went on as before with the sailors dutifully taking their lime juice every day to the extent that they became known as limeys.

The funny thing is nobody noticed this big mistake at first because it coincided with the invention of steam power.

And suddenly British boats were moving a lot faster, voyages were a lot shorter, and so scurvy was a lot less of a risk anyway.

And it was only when there was an Arctic mission and everybody took their lime juice and the expedition had to be abandoned because they all got scurvy.

And that's when it was discovered what a big mistake had been made.

It was very humiliating because the British had been boasting that they could keep a crew scurvy free for months and months and months.

And they certainly couldn't.

This is not a very flattering story for me and my compatriots.

To be fair to all you Brits, few people had a good understanding of fruits and vegetables and nutrition at the time.

We didn't even know what vitamin C actually was until it was isolated in 1927, and that discovery won a Nobel Prize.

But the Brits weren't the only ones to get confused about lemons and limes back in the citrus grove.

I asked Tracy about them.

What's the difference between a lemon and a lime?

Well, okay, first of all, you have to know the fact that limes, when they're mature, are actually yellow.

But we market them in the United States as green to distinguish them from lemons.

But that's not the case in other countries.

Right, and just to add to the confusion, those ripe yellow limes, they're known as limon in some places.

I have stumbled into that trap in Mexico.

Lemons do have different characteristics, but some limes, especially if you get into the bears and tahiti limes, have a somewhat similar shape to a lemon, whereas the small ones that are really acidic have a little different shape.

But even the acid-less ones can look very much like a lemon.

Lemons and limes have slightly different genes, and so they taste different.

And then even within lemons and limes, there are mutations that change the flavor.

Okay, so this is

amber lemon, and you can see it has sort of an amber color to its flesh.

And it does taste like a lemon, but it is a little bit sweeter.

Mm.

Yeah, it tastes like a lemon, but it's not as puckery.

Not as acidic.

Oh, this is the kind of lemon you could just eat.

Tracy compared the sweet amber lemon to one called the feminello.

They grow in Italy, and they're used to make limoncello.

Do you think it has a different taste?

It does have a different taste than amber, but so don't take a huge bite of it.

Yeah.

Can't eat it the way you could the other.

And so now, since we're doing lemon.

Oh, that's acidic.

It makes you realize how sweet amber is.

Sweet or sour.

Either way, lemons have a dark side.

Yes, indeed.

Well, I mean, I think we can blame lemons

for the roots of the mafia as we know it today, which is an extraordinary responsibility.

You heard that correctly.

Helena thinks lemons are to blame for the mafia.

And this is because, well, it's all about one place at one time, and the time is 1860, which is when Italy was changing from being a disparate collection of states and principalities ruled by foreigners and the Pope and a few dukes, Italian dukes and princes, into a unified kingdom.

And the place was a place called the Concadoro, which was an area of level land between Palermo on the west coast of Sicily, the mountains and the sea.

And at that time, and in that place, growing lemons was the most lucrative form of agriculture in Europe, which is extraordinary.

Remember, that's mostly because of the the scurvy connection.

The Italians were supplying the British Navy.

It's also because they were shipping to America, which didn't have its own citrus industry yet.

So you can see why everybody wanted to become a citrus farmer.

And this is how the mafia starts.

The first thing you have to know is that, sure, lemon farmers could make a lot of money, but first they had to spend a lot of money.

They had to invest money to dig wells and provide irrigation.

They had to build access roads.

They had to build barns to store their fruit and their tools.

They had to build walls because lemons are very tender and the Concadora is right by the sea.

And when they'd done all that, they bought little tiny lemon trees and planted them.

And it would be eight years before they got any return on that enormous investment.

And this is where the original mafia members see their opportunity.

People think that the first mafia operators were sort of disenfranchised Sicilians in the most impoverished parts of the island.

In fact, that's wrong.

They were the big aristocratic landowners on the Concaduro who spotted these new investors and what they do then in the 1860s is exactly what the mafia do today.

They turn up like your favourite uncle.

So if you open up a new restaurant, say, these friendly neighbours come along as you're putting the final touches to the decor and they say hey it's so cool you're opening this place we really want to help you.

How about I supply your bread?

In the 1860s they'd come and say do you know it's really expensive digging your own well and we've got more water on our farm and we've been here for years.

We've got more water than we know what to do with.

We'll supply your water.

And they would give you a contract that was so obscure and so full of arcane references and subclauses that that they had you over a barrel immediately.

Because if you didn't fulfil the contract that you'd signed by paying them when they demanded it, they could just cut your water off.

They also controlled the transportation to the docks and the dock workers.

If you didn't pay them, your fruit wasn't going anywhere.

And so they had the whole industry absolutely in their hands.

And it's here really that you see the beginnings of mafia behaviour because you've got intimidation.

You know, if you said no to any of the services they were offering, the same guy who'd come and offered you so kindly so much help would dispatch a gang to scale the walls of your lemon grove, hack down your trees, smash up your irrigation plant and spoil your fruit.

The intimidation and violence became so pervasive that when a researcher visited Sicily in the late 1800s he was horrified.

And he said that area, the Concadoro, when you see it for the first time it looks like the most beautiful place in the world.

But when you hear what's going on and how people are being murdered and how the mafia is exploiting people, you'll begin to think, as he does, that the scent of orange and lemon flowers reminds you of the smell of corpses.

Obviously, the mafia have gone on to diversify their operations and go into all sorts of different industries, slaughterhouses, the drug trade, and on and on.

But they got their start in citrus.

Those protection rackets, pay us and you won't get hurt, that all got its start in the Sicilian lemon groves.

That's where the mafia developed their signature style.

This has kind of changed the way I look at lemons.

But that's history.

And there's something lurking in the citrus groves today that makes the mafia look like pussies.

Wang Long Bing.

It is not a scary Chinese gang taking over from the mafia, it's citrus greening disease, or HLB, that's what most American scientists call it.

Millions of trees are, in fact, in Florida.

So in Florida, the production,

right now is about a quarter compared to 10 years ago, just only 25%.

And that's really owing to this one single disease, not anything else.

And also, the whole acreage in Florida now that's actively producing fruits in the industry is equivalent to before World War II level.

So it was

really that bad.

Wen Beauma is one of Tracy's colleagues at UC Riverside.

She's a researcher in plant pathology and microbiology, and she just won a multi-million dollar grant to work on how to protect trees from HLB.

HLB is a bacterial disease, but it's transmitted by insects, specifically this one Asian psyllid.

It's like a little jumping fruit fly that feeds on citrus trees and brings the bacteria along with it.

It's like mosquito, how mosquitoes spread malaria.

Scientists aren't exactly sure when or where the disease originated, but it was first described in China about 100 years ago.

That's why it has a Chinese name is called Huang Longbing, and this Chinese name means yellow dragon disease.

And it's called yellow dragon disease because when the tree was infected, the symptoms are very sectioned.

So it's only showing some yellowing of leaves on one part of the tree or separate parts of the trees.

So when you look at the tree from a distance, you sort of see this sectioned yellowing on the canopy.

So it looks like yellow dragons.

And what it is, is like an immune disease for trees.

It damages their internal plumbing.

The root systems and all the nutrient pathways in the tree gradually collapse, which makes it harder and harder for the tree to stay healthy.

And so they just get weaker and weaker.

But that can take many years.

And a lot of people are having this analog of citrus HLB to ACE of humans.

People with HIV infection, they don't die of HIV.

It's because their immunity is compromised and they diet from other infection.

It can take years before before the trees die.

During that time, the psyllids are still feeding on those trees and are infecting other citrus trees nearby.

And meanwhile, the fruit of the infected trees, that's suffering too.

The fruits are usually green, so that's why this disease is also called the greening disease.

The fruits are,

they don't look like they will ever ripe.

And when you cut them, you have one half is larger, the other half is small, and the tastes change.

Oranges from a tree infected with HLB taste really sour and not in a good way.

Although this disease popped up in China a century ago, it didn't go anywhere for 70 or 80 years.

But then it was identified in Brazil in 2004, and then in Mexico, and then in Florida.

Those places mostly grow oranges for juice, and their citrus groves have been decimated.

The situation in Florida is really bad.

They are so highly infected.

I've heard

different numbers, but I've heard anywhere from 80% to 90-something percent infection.

And the thing is, there is no cure.

Once a tree is infected, that's it.

There's nothing we can do.

So, we want to prevent the infection from happening at the beginning.

And for that, spraying is obviously the most important way.

You have to, if you kill all the psyllids, then they won't be able to transmit.

But that's expensive, and there's a huge environmental cost too, to using all those pesticides.

So, there's another strategy: find and get rid of the infected trees so that the flies can't feed on them and transmit the infection.

In Texas, I know that's what they do.

They train these scouters and they go out and they walk through the alchers and find potential infected trees.

And for trained eyes, they're actually really good at spotting these.

But the problem is that these are trees with symptoms.

And we know the trees can be infected long before they show any symptoms.

But in Florida, they're past the scouting stage.

There are so many infected trees that the farmers just keep those trees alive.

They don't have any other choice.

I mean, the only solution is to try to make them live longer and produce just a little bit more fruits for the farmer to get a little more things back.

As you can imagine, this has all created a little bit of a sense of urgency in the citrus community.

Researchers are frantically trying to come up with ways to tackle it.

Last summer in our field recordings episode, we spoke to a Florida scientist who's testing a way to lure male flies into a trap using the sound of a horny lady citrus psyllid.

Scientists have been trying genetic engineering.

They've put spinach or pig genes into the trees to protect them from the disease.

At UCR, they're breeding orange trees with a cousin, a variety they found in Tracy's collection.

This cousin seems to be resistant to HLB, and so the hope is that resistance will transfer.

Wenbo is also trying genetic engineering, but with a little bit of a twist.

She's not adding genes, she's deleting them.

The idea is to make the tree immune to the specific toxins that the bacteria secretes.

And she has another idea about those toxins.

She wants to find a way to identify them early on before the tree shows signs of the disease.

It could be an early detection system to help prevent the spread of HLB.

Wenbo's research project just got funded as part of the big U.S.

Department of Agriculture effort to push forward more than a dozen different promising approaches to the problem.

They're kind of throwing the kitchen sink at it right now because it's really scary.

You're gonna consider if we don't have a very effective way of treating this, manage this disease.

California and Texas may be like Florida now.

And, you know, in the next 10 years, we could have very, very little citrus production, which means that you have very, very little or no citrus juice, and not to mention fresh fruit.

And billions of dollars, billions of dollars and jobs.

California growers are crazy nervous about this disease.

It's only just reached the state.

Tracy said they found 12 trees with the disease, but the threat is real.

Standing in the UC Riverside Citrus Variety Collection, surrounded by hundreds and hundreds of glorious citrus trees with their clouds of fragrant blossoms and the golden orange fruits, you really feel what we could stand to lose if Wenbo and her colleagues don't succeed.

There are just so many amazing different varieties that most of us have never even heard of, let alone tried.

Have you ever heard of Australian finger lime?

Nope.

My husband said he thinks they look like coyote turds, which would not be a very

saleable, that name.

The coyote turd variety they're calling it the caviar lime but it's not a lime at all so it's shaped like small maybe coyote like a coyote turd purplish on the outside blackish purple so sort of like coyote turd color when you cut them open the juice vesicles are on little stalks so they look like bubbles or like caviar and that's why people are calling it caviar lime and they taste like lime a limeish flavor i've actually tried this a specialty citrus grower in la gave me one to try It has this pop rocks quality to it.

It sort of fizzes on your tongue.

I loved it.

I didn't get to try that one on this trip, but I tried so many different ones.

I have lots of favorites.

What's your favorite right now in this particular season?

Or favorites?

I've been eating a lot of blood oranges.

There's one I'm eating right now that's called the kuzba.

It's from Tunisia.

Oh, tango's really good.

I think tango's good.

I like gold nugget.

Lots of them.

I like Tahitian pomelo.

She cut open a Tahitian pomelo.

It has a pale green tinge to the flesh.

Oh yum.

I love this.

This is nice.

This has a really nice blue.

I really like this one.

Oh this is amazing.

So good.

That was probably my favorite one of all.

I'm still dreaming of it.

It's got this sweet yet acidic flavor.

It's really fresh tasting.

It has an almost green grassy note to it.

My favorite that Tracy showed me when I was there was this gorgeous multicolored lemon.

Did you see that one?

I did.

It was crazy.

And this is a sport or a mutation of a eureka called variegated pink-fleshed eureka lemon.

And the fruit are actually striped when they're very young.

They're actually pink inside.

So green and yellow striped and pink inside.

Yeah, green and yellow striped and pink inside.

It's kind of cool.

Let's cut out over one more.

Okay.

I think it's really super pretty.

Flavor-wise, it just kind of tastes like a lemon.

But oh my god, it is beautiful.

Really?

We have lots of photos from the Citrus Variety Collection online.

Check them all out at Castropod.com.

So Cynthia, the thing for me about visiting was that I realized that, you know, I shop for apples by variety.

I know which kind I like.

Cox's orange pippin.

Hard to find outside the UK, but worth it every time.

I've been known to grab all sorts at the market to try.

There's honey crisp and pink lady and maccoon.

Right, but with oranges, I just would buy oranges.

I didn't think about all the different varieties and how they taste so different.

It's something I think we're all just starting to learn.

It's not just tangerines and navel oranges.

There are different kinds of blood oranges, and there are Meyer lemons and Oro Blanco grapefruits.

And my new grocery store favorite, the Decapon, which has this enormous wrinkly jacket and incredibly juicy tangerine-y flesh inside.

Because I used to live in Israel, I'm kind of obsessed with pomelos.

They're common there and very hard to find in Boston.

But even in Israel, I'm not sure I had anything like that Tahitian pomelo.

Basically, it's time we all got excited about citrus.

I'm excited.

I am too.

Now let's just hope that Wenbo can keep the industry alive.

No pressure there.

That's it for this episode.

Thanks to Givodin, a 200-year-old flavor and fragrance company.

They celebrated their 10-year collaboration with the UCR Citrus Variety Collection, and we want to thank them again for flying me out to California to join the festivities.

Thanks to Tracy Kahn, director of the UCR Collection, for introducing us to the many wonders under her care, and to Wenbo Ma, whose research will, we hope, help solve the scourge of citrus farmers today.

I have photos from my visit visit to the citrus variety collection on our website at gastropod.com.

And thanks to Helena Attlee, her gorgeous book is called The Land Where Lemons Grow: The Story of Italy and its Citrus Fruit.

If you love citrus, or if you love Italy, and who doesn't love one or both of those, then this book is definitely worth a read.

This month on Explain It To Me, we're talking about all things wellness.

We spend nearly $2 trillion on things that are supposed to make us well: collagen smoothies and cold plunges, Pilates classes, and fitness trackers.

But what does it actually mean to be well?

Why do we want that so badly?

And is all this money really making us healthier and happier?

That's this month on Explain It to Me, presented by Pureleaf.