Mexico City — Citrus growers in Mexico's Gulf Coast state of Veracruz guard their groves as lime prices surge to the point that pistol-packing thieves pick pieces of fruit right off their trees.

Truckers, meanwhile, travel with escorts — especially after criminals started targeting their vehicles and commandeered a cargo of limes worth nearly $50,000 this month. "There are a lot of people stealing limes, even entering the groves with weapons," says Adriana Melchor, director of fruit exporter Inverafrut.

Limes have always been a coveted crop in Mexico, where a squirt of the small citrus brightens the taste of everything from tacos to tequila to guacamole. But a combination of poor winter weather, plagues and threats from organized crime have caused production to plunge and prices to rise — a trend that has many Mexicans calling the citrus "green gold."

Newspapers are covering the shortages as prices rise to more than $6 per kilogram (2.2 pounds) in some places. La Prensa, a tabloid catering to the cost-conscious working classes, replaced its usual blood-soaked front-page photos with the headline: "Like Meat!" and a subhead saying limes sell for the same price as chicken.

Vendors say sales are on the decline, even though limes — along with chilis and salt — accompany many Mexican dishes.

"One year ago they cost 15 to 20 pesos ($1.15 to $1.50 USD) per kilogram. Now they are at 50 pesos," ($3.80), says Mario Aguilar, who sells fruit from a market near the president's residence in Mexico City and reports people purchasing half of what they used to buy.

Taco stand operator Fidel Gonzalez used to put out bowls of limes for his patrons. Now he portions slices to keep costs down. "We have to charge the same price for our tacos, so we give out less limes," he says.

The quality of limes is lacking, say growers and restaurateurs.

"We're getting a smaller-size lime and it doesn't produce as much juice as it should," says Claudio Hall, chef in Fonda El Refugio in Mexico City, where his bartenders now use twice as many limes to make margaritas. "We just tighten our belts and pay the higher prices," he says.

The consumer prosecutor's office, Profeco, says prices have on average increased by 221 percent since December and promises to prosecute anyone hoarding the fruit or speculating. Profeco's director, Lorena Martinez, said the sanctions for speculation include prison terms of up to 10 years.