ALFREDO ESTRELLA via Getty Images Two former 'punteros' (informants) of the Templar Knights drug cartel pose during an interview with AFP at la Nopalera community, Michoacan state, Mexico, on February 15, 2014. Presently the two young men are part of the community's self-defense group. Mexican federal forces have taken over police duties in some 20 towns in the restive state of Michoacan, where vigilante groups are fighting a drug cartel. Michoacan, where much of the population lives in poverty, has become the most pressing security issue facing Mexico President Enrique Pena Nieto, who inherited a bloody war on drugs. AFP PHOTO/Alfredo Estrella (Photo credit should read ALFREDO ESTRELLA/AFP/Getty Images)

In some cases, Canadian supermarkets are now charging well over a dollar for a single lime.

The cold weather and agricultural pests have played a part in curtailing lime production and so raising the cost to consumers. But there is another factor at work here as well: In fact, the price of limes in Canada is closely tied to one of Mexico's infamous drug cartels.

While these cartels are known for their tight control of drug production and export, they are also branching out into other businesses, limes being one of them.

Limes are an essential ingredient in much of Mexican cuisine, and one of the country's key exports.

The green citrus fruits are largely grown in one specific region: the state of Michoacán in the country's southwest. And that's where a cartel called the Knights Templar has been elbowing in.

Gustavo Arellano, a syndicated columnist and author who writes about Mexican cultural issues, says the Knights Templar have been making their presence known in an area called La Tierra Caliente for a few years now.

"So what they've done over the last couple of years, is that, if they're nice, they put humongous taxes on the farmers. If they're not nice, they just kill farmers and take the land and take over lime production themselves."

Starting last year, however, things began to change in Michoacán, when local militias began to spring up in opposition to the Knights Templar cartel.

Those local militias, which are often backed by lime farmers, have been somewhat successful at curtailing the cartels. And the Mexican government has found itself caught in the middle.

"It's been somewhat chaotic given that you've had these 'alto defentas' fighting the cartel," Arellano said. "The cartels have been in retreat ... but as a result they're trying to up their antics with the Mexican military stuck in the middle. So when you have such chaos in the region, price speculators are just going to drive the price of limes up."

Canadians tend to pay a premium for limes anyway, which are generally unit-priced, a few for a dollar. But now, some stores are selling limes for as much as $1.50 each.

In Southern California, where Arellano lives, limes used to sell for about $40 per case. Now, the case lot price is closer to $100. He said that price increase is now being passed on to consumers, with some restaurants charging for small wedges of lime.

"Others [are] giving people lemons ... and of course the consumer knows the lemon is nothing like the lime.

"There is a bar here called Matador Cantina where they have a special: Give us a bag of limes and we'll sell you a margarita for a quarter. But they're trying to rip people off. A bag of limes is really more valuable than a margarita."

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