A looming shortage of tequila wouldn't usually be an AlertNet crisis, but in this case it could be a sign of hungry times ahead.

Mexican farmers are torching fields of blue agave, the cactus-like plant used to make the fiery spirit, and resowing the land with maize as soaring U.S. ethanol demand pushes up prices.

The spiky-leaved agave plant can take eight years to reach maturity, so cutting them down and burning out the roots isn't something that can be turned around easily.

Troubled farmers are hoping to cash in on the biofuels boom, but there have been protests over rocketing food prices in Mexico, where maize is the staple food.

In China, gas stations in some provinces already mix 10-percent ethanol into the gasoline they sell. The problem is that the increasing use of maize for industrial purposes in ethanol production is driving up the cost of corn for agricultural use, mainly to feed pigs. The knock-on effect is a dramatic rise in the price of pork, one of China's most widely consumed food staples.

The Christian Science Monitor quotes Chinese political analysts who say the government is afraid that rising food costs could affect social stability. Inflation was an important factor in sparking the pro-democracy protests in Tiananmen Square 18 years ago.

Authorities in Beijing are trying to impose limits on the production of ethanol using traditional food crops, but they are hard-pressed to keep a lid on the large and small ethanol factories which are springing up in China's corn-producing regions and are starting to compete with animal-feed manufacturers for raw materials.

Chinese projects are under way to make ethanol instead from cassava - a starchy tuber common in Africa but not used as food in China - and jatropha, also inedible and grown in wastelands.

African food prices are feeling the impact of the biofuel boom too, with South African maize shooting from $85 a tonne in recent years to $282 a tonne in March, U.N. news service IRIN reports.

In Asia, palm oil is the big biofuel focus. Used in toothpaste, cookies, ice cream and breads, it's the world's second most popular edible oil after soy, and Malaysia and Indonesia together produce 83 percent of it.

They've already come under attack for clearing forests to plant palms for biofuel production. Apart from the environmental consequences of huge fires and diminishing forests, campaigners say orangutans could be extinct in 10 years because the animals' habitat is shrinking and they're sometimes killed for straying into palm plantations.

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