Along with Russia, Venezuela, Iran and the Dubai property market, add another name to the list of bubble economies hurt by the falling price of oil: the ethanol industry. And naturally, the ethanol lobby is looking for a bailout on top of its regular taxpayer subsidies.

The commodity bust has clobbered corn ethanol, whose energy inefficiencies require high oil prices to be competitive. The price of ethanol at the pump has fallen nearly in half in recent months to $1.60 from $2.90 per gallon due to lower commodity prices, and...