A worsening agave shortage is causing price spikes in the tequila industry and could lead to shortages even among major manufacturers. Agave is the key ingredient in making the alcoholic beverage.

Reuters reports the price of the plants has risen sixfold in the past two years. And since Agave takes seven to eight years to reach full maturity, some tequila makers have been using young plants to fulfill demand from tequila companies. Those, in turn, produce less tequila and lead to a cascading problem of fewer fully mature plants the following season.

Farmers are planting more agave plants, but still can’t keep up with demand—and the added threat of theft (some 15,000 plants were stolen last year, a three-fold increase over 2016) is making the problem more severe.

The shortages are expected to continue through at least 2021, which could lead to some tequila companies going out of business as they’re forced to raise prices (and can’t compete with other spirits).