When Cinco de Mayo revelers line up tonight at their local watering holes to celebrate the holiday, they may find their respective margaritas and tequila shots paired with a jarring garnish: lemons.

Local shortages have caused a rapid spike in the price of limes, so bars and restaurants across the country have been eschewing the tangy favorite in favor of their less expensive yellow cousins. And while the absence of limes from one’s favorite beverage might seem like a minor annoyance, the shortage is tied to a very serious crisis in Mexico.

Over the past year, the cost of limes has quintupled, going from roughly $20 for a 38-pound case to “over $100 per case at present”. The cause of this increase? For one, heavy rains late last year damaged crops in the Mexican states of Michoacan, Guerrero and Veracruz hurt the crop. The United States imports nearly 95 percent of its limes from Mexico, so when those damaging rains were coupled with an outbreak of a citrus-killing bacterium in the lime producing state of Colima, this year’s lime yield began to cause headaches for bar owners and tequila connoisseurs alike.

Joe Hargrave, owner of the popular Bay Area restaurant chain Tacolicious, told the San Francisco Chronicle he had to raise the price of fresh lime margaritas at his stores by $3, while John Berry, owner of the prominent Mexican eatery La Fonda in San Antonio, told Reuters he decided to stop buying limes entirely.

Yet, there is a second reason for the increase in lime prices–one that carries a much heavier weight than sour pallets and light wallets that connects to the United States’ war on drugs.

In Michoacan, the lime-growing capital of Mexico, the Mexican crime cartel known as The Knights Templar have found a new product to push north of the border: limes. A splinter group of La Familia Michoacana, the drug cartel dismantled by law enforcement around 2011, the Knights Templar were looking for a way to diversify their business in the wake of La Familia’s downfall. With drugs becoming increasingly more difficult to smuggle across the U.S. border, the Knights Templar decided to diversify their business interests, using kidnappings and violence to terrorize and extort those involved with lime export in Michoacan. Business owners in the area have pushed back by forming vigilante “self-defense” groups, which have battled the drug cartels in violent shootouts. As the unrest has spiraled out of control, so too has the price of limes, and it is now virtually impossible for U.S. officials to guarantee how or where Mexican limes are grown.

“Most people in the U.S. don’t realize how highly dependent we are on Mexico for certain products. They don’t understand how much our economies are intertwined. The bad things happening in Mexico do have an impact on U.S. consumers and U.S. exporters,” David Shirk, a security specialist at the Mexico Institute of the Woodrow Wilson International Center for Scholars, told CNN. “The influence of organized crime groups is extremely pervasive and affects daily life in ways that are shocking. It’s part of daily life in Michoacán and one of the unintended consequences of the drug war.”

While the price increases have begun to recede from record highs in April, many restaurants are now staying away from purchasing limes for a moral reason: afraid that by doing so they might be supporting violence south of the border.

“I’m not playing that game,” said Alexeis Filipello, owner of Bar Dogwood in Oakland, to the culinary blog Alcademics. “I hope Mexico has case upon case of rotten limes and the cartels are forced to sell drugs again instead of strong arming lime farmers.”

While the violence in Michoacana continues to escalate, the Mexican government has attempted to quell the unrest by sending a military presence into the state, while telling the vigilante groups to stand down by May 10. It remains to be seen if they will listen to that call.