MR. KOJO NNAMDIYou know, around 98 percent of the limes we consume in the U.S. come from Mexico. Our neighbor to the south is in fact the world's largest producer of limes. But those limes are in short supply these days for a host of reasons, including disease, weather and even drug cartels. And that's meant a serious spike in prices. Those higher prices are affecting supermarkets, bars, Mexican restaurants and anyone else who wants to make drinks or dishes with the tangy citrus.

MR. KOJO NNAMDIJoining us to talk about what's behind the shortage is David Karp. He writes the Market Watch column for the L.A. Times. He is also a citrus researcher, affiliated with the University of California Riverside's Department of Botany and Plant Sciences. He joins us by phone from Los Angeles. David Karp, welcome.

MR. DAVID KARPHi, Kojo, thanks for inviting me.

NNAMDIDavid, how much of an increase in prices are we seeing?

KARPWell, over the last two or three months, supply is down by two-thirds, from 90 to 30 truckloads a week. And prices are up by about 500 percent from 20 or $25 for a standard 40-pound carton to about $100 or more these days.

NNAMDI800-433-8850 is our number. Have you seen or noticed the spike in lime prices? Give us a call. Do you own a bar or restaurant? Has the lime shortage affected you? 800-433-8850 or shoot us an email to kojo@wamu.org. David, so can you explain what's hitting the lime market to cause this price spike?

KARPWell, it's a confluence of the three causes that you cited. Probably the most important in the short term is adverse weather, serious rainstorms last fall knocked the blossoms off the lime trees in many regions of Mexico, including the largest producing region that exports to the United States, Veracruz and Tabasco. And that's what's causing the current shortage. However, there is a bacterial disease, the worst disease in citrus trees, Huanglongbing, that in the long term is a much more serious threat.

KARPAnd I could tell you about that. It's a little bit tricky because the region that exports to the United States is not seriously affected now. In fact, the Mexican said that the disease is not prevalent in Veracruz. However, I was just having lunch yesterday with some citrus scientists who were on the west coast of Mexico and it's much worse than the Mexican government or citrus pathologists down there are letting on.

KARPThere are regions of Mexico where 100 percent of the trees are infected and will all be dead within a couple of years. (word?) Colima, that's on the west coast of Mexico.

NNAMDIYup.

KARPAnd it primarily produces the small fruit, so-called key lime that's preferred by Mexicans and grown about half of the acreage in Mexico. And production there is, according to officials, that says that it's down by 30 percent but I think it's a lot more. And the disease is spreading to Mexico. There is no cure. It's going to just get worse and worse and worse. So it may very well be that, at least in the medium term, the era of cheap limes is coming to a close.

NNAMDIAnd what are the drug cartel related or causing?

KARPThat's tricky. You have to go state by state and see what the situation is. In the state of Michoacan, which is famous not only for its limes but for its mangoes and avocadoes among other produce that's exported to the United States varies too. But that state has been largely controlled by that Knights Templar drug cartel. And they've been battling with vigilantes, with possibly other cartel interests and with the Mexican government for control of that state, which has disrupted shipments.

KARPProbably the most important factor, however, in terms of the security situation in Mexico adversely affecting lime shipments to the United States, when the price spike, suddenly -- limes in the past have generally been a very low priced commodity. They only brought the farmers a few cents each. Now it's green gold worth five or six or eight times as much. And so, criminals, to what extent they're affiliated to drug cartels is certainly hard for me to say, sitting here in Los Angeles.

NNAMDIBut they're organized.

KARPBut criminals have been stealing the fruit from the trees and from truck shipment coming -- headed north to the American border being hijacked.

NNAMDIWhoa. You mentioned earlier key lime. Can you go over some of the basics? What kind of limes, key limes are apparently favored by Mexicans. What kind of limes are we talking about that we typically get in our grocery stores?

KARPThere are two kinds of limed, the small fruited, rounder, seeded key lime preferred by Mexicans. And that's the true lime, the original lime, Citrus aurantifolia. And that only accounts for just like 5 percent or so of lime sales in the United States. The bulk of sales, 95 percent or more consists of, as they're called in Mexico, confusingly enough, Persian limes. They're also called Tahiti limes or in California Bearss lime.

KARPThat's larger fruited, it's seeded, it has a longer shelf life and that's the preferred lime here in the United States, although it's not quite as aromatic as the key lime. And I noticed something very interesting. Just looking at the terminal market prices. In Los Angeles, at least, where a lot more key limes come in than come in to New York, the prices have fallen by half over the course of the last month from $50 for a 36-pound to $25.

KARPAnd that's to the extent that they're available there on the East Coast, that's an excellent substitute. I encourage your listeners to investigate key limes or they're sometimes called, confusingly enough, Mexican limes or West Indian limes. But they're much smaller than regular limes and more aromatic, and now they're cheaper too.

NNAMDIYup, I remember those limes from growing up in the Caribbean. Here is Cathy in Forestville, MD. Cathy, you're on the air, go ahead please.

CATHYHi, Kojo and guest. I just have a very simple question. Whenever I go grocery shopping, I try to buy local, U.S., organic whenever I can, and I've never understood why if the U.S. can grow lemons and grapefruits and oranges, why we can't simply grow limes. You know, why the limes are always from Mexico. And I just never understood that.

NNAMDIIt's why we have David Karp here. David?

CATHYThank you.

KARPWhat a great question. You know, when I was growing up, and I hate to say it but it was like 40, 50 years ago, most of the limes in the United -- consumed in the United States came from southern Florida. Limes are the most tropical of citrus fruits, more so than lemons and can only be grown in the United States at the southern tip of Florida, Texas and California because they're too cold tender to be grown further north.

KARPNow, those plantings in Florida were very considerable at one point. There are 7,000 acres as recently as 30 years ago. There are virtually none now. What happened? Three things. One, low priced competition from Mexico. When limes are coming across the border for $5, they're $5 at McAllen, TX in a typical year, or has been in the past. Very hard for an American to compete with our higher cost of land, labor, inputs, water, et cetera.

KARPNow, then Hurricane Andrew in 1992 devastated the planting in southern Florida. And just as they were getting back on their feet, another serious bacterial disease, canker, led to a mandatory eradication, a program that basically wiped out all the lime trees in Florida commercially at least. There may still be a few in backyards, but that doesn't supply commercial production.

KARPThere might be very few trees in southern Texas. California, however, is the largest domestic producer and yes we could grow limes in somewhat larger quantities. However, couple of things. We've got 400 acres now down from a thousand a decade or so ago. Again, the main problem is competition with Mexico, number one. Number two, a very -- prices for water has spiked so that nobody in their right mind would be planting limes.

KARPThey can only be grown in north San Diego County, prices for water have gone through the roof. And third, there's also the threat of disease here. So California produces about 5 million pounds of limes a year. The total American consumption is 810 million pounds. So that tells you it's just a drop in the bucket. And our production here is from basically August to December, a little bit year-round. I've got a lime tree in my yard, I can see it from here, and it's got a few limes on it.

NNAMDIBut, David, our consumption in the 1970s was not as great as it is now. What in fact has led to the increase in our consumption of limes? We never used to apparently like them as much as we do now.

KARPWell, consumption 30, 40 years ago was less than half a pound per capita annually. Now it's two and a half pounds. It's largely ascribable to the increased immigration from tropical countries. Lime is the lemon of the tropics. It does much better in tropical countries than lemons do. So anyone looking for a souring agent, well, Latin America or Southeast Asia is used to using limes.

KARPAnd partly as a result of the change in immigration policies in the 1960s, there's been a great influx of immigrants from countries where limes are native. And a consummate increase in the taste for the food of, say, Mexican food or Thai food or something like that from countries where limes are prevalent.

NNAMDIThank you very much for your call, Cathy. We move on now to Reid in Bethesda, MD. Reid, you're on the air, go ahead please.

REIDHi. I was just wondering why we couldn't import limes from, like, India or elsewhere in Asia where I think lots are produced?

NNAMDIDavid Karp?

KARPOkay. Very good question also. Yes, they are producing quantities there. However, they have very serious diseases. Like, Brazil produces huge quantities of limes and exports them to Europe, but they're got a disease called citrus variegated chlorosis that basically for plant health reason, those limes are not allowed to be exported to the United States. Same thing in Southeast Asia.

KARPNow, Mexico has this disease and we're bringing in key limes which has this that could theoretically transmit the disease here. But that's a political and trade hot potato. Anyway, the short answer is, just because something is grown somewhere doesn't mean they can send it to the United States. There has to be U.S. Department of Agriculture approval and that does not exist for other lime-producing countries.

KARPThere is -- there are small quantities, larger right now because of the high prices, being imported from other countries in Latin America like Colombia and Ecuador and the countries in Central America. But they're a drop in the bucket compared to Mexico's 800-pound gorilla.

NNAMDIReid, thank you very much for your call. We're talking with David Karp. He writes the Market Watch column for the L.A. Times. He's a citrus researcher affiliated with the University of California Riverside's Department of Botany and Plant Sciences. We're discussing lime prices and moving on Daniel in McLean, VA. Daniel, you're on the air, go ahead please.

DANIELHi, Kojo. How are you today?

NNAMDIDoing well.

DANIELAwesome. So this is going to sound oddly optimistic given the circumstances. But...

NNAMDISure.

DANIELYou know, I work in restaurants and one of the things that we've sort of been forced to do because of the price of limes is start looking locally not for a source of citrus but rather for source of acid for both food, in our dishes and also in pastry and then of course in cocktails. And so one of the things that we started to see is that we've been using vinegars. Actually, we found two really cool sources in Virginia.

DANIEL(word?) Farm Vinegars and Virginia Vinegar Works. And then, we've also started to use things like granny smith and apple juice for ascorbic acid, different berries. Later on in the summer, we're probably going to be looking towards tomatoes for all of our acidity. We're using green tomatoes right now. But, you know, it's really making us a little bit more creative. I think it's actually, sad to say, but it's probably better in the longer term because it forces us to go local for something we've always sourced from outside of the country.

NNAMDIYeah. But if I insist on lime in my margarita, what do you do?

DANIELI mean, honestly, people have insisted on certain ingredients for certain dishes for the entirety of...

NNAMDII know what you're going to do, you're going to try to fool me. Is that what it is?

DANIELI wouldn't fool you. I mean, I would offer you, you know, an honest alternative and see if you like it. And if you don't, we can always find something else that you'd be interested in. But in the meantime, I'm sure that this is something that would work. And, honestly, there are places that are trying to confuse about those limes and the market will start to trend people toward those places and that's fine, because I think that a lot of people will be just as interested in something that maintains the same quality that isn't what they're used to.

NNAMDIYou know, Daniel, that is universal in the way where shortage has spur creativity and that seems to be what is happening here. But thank you very much for your call, Daniel. David Karp, it's not only limes. Criminal cartels now control large portions of other produce apparently. Can you talk about that?

KARPYeah. You know, I just know that because I go to a lot of horticultural conferences and when I speak to consultants who spend a lot of time down in Mexico, they tell me shocking stories how things have changed over the last three to five years. It used to be that they could out in the middle of the day and at night they could just hang out and pretty much perfect safety. Now, in many regions of Mexico, they only go in the middle of the day, never in the morning, evening or night.

KARPThey don't tell anybody where they're going and they tell me stories of packing houses being burned down in the dead of night of growers who were afraid to go out in their field, who are afraid to even dress like a grower because they're afraid of being killed like other people have been killed in their field, so they can't really take care of their plantings anymore. They tell me about growers who receive a you can't refuse this offer of silver or lead, if you know what I mean.

KARPMainly, they're told by drug cartel interest, we're taking over your land and take this tenths of a payment or you're dead. I hear of packing houses that have been taken over by drug cartel interests that are interested primarily in laundering their money and not so much in the food trade. What are the implications of that for the health and availability of the produce that's coming into the United States?

KARPMore and more of the produce we consume is imported, almost half now at this point. And by far the largest exporter of produce to the United States is Mexico, if not in all states of Mexico. So, really what somebody -- I challenge if there are any journalists listening, it's not going to be me because I don't speak Spanish and I'm not suicidal. But if somebody needs to spend some time in Mexico, very well guarded I would hope, and ask these questions for each individual commodity in different growing area, what is the effect on American food supply?

KARPAnd the last I've seen callous in regard to the effect on the Mexicans themselves, whatever the inconvenience to American margarita lovers caused by the current lime shortage, that's trifling compared to the anguish of Mexicans whose lives and livelihoods have been destroyed largely by the blowback from our drug policies.

KARPI'm not a drug policy expert and I'm not suggesting that we do one thing or the other, but I think we should take into account that by creating this high-priced commodity that led to that prevalence of drug crime in Mexico, there is an effect on our very own food security.

NNAMDIFinal question, David. We only have about a minute left. This particular crisis with limes is likely to be temporary. What do you expect to happen?

KARPWell, what I'm hearing from importers is that a new crop's coming on, so prices should go back to the 30s by June and there should be plenty of limes this summer. Limes are generally abundant. And even though they may be slightly less abundant than usual, there will be plenty of them and not at these super-high prices.

NNAMDIWell, I guess there are a lot of people who will be glad to hear that. David Karp writes the Market Watch column for the L.A. Times and he's a citrus researcher affiliated with the University of California Riverside's Department of Botany and Plant Sciences. David Karp, thank you for joining us.

KARPThanks so much, Kojo. It's a pleasure.

NNAMDIAnd thank you all for listening. I'm Kojo Nnamdi.