Ethanol tumbled, widening the discount to gasoline, as cheaper corn enabled distillers to boost production of the biofuel. The spread widened 7.38 cents to 79.99 cents a gallon, the biggest one-day expansion since Oct. 4. Pratt Energy said Oct. 24 that it restarted operations at a plant that was idle for more than five years. “There’s been news of plants coming back online,” said Will Babler, a broker at Atten Babler Risk Management in Galena, Illinois . “It seems like production is trending higher.” Denatured ethanol for November delivery fell 3 cents, or 1.6 percent, to $1.831 a gallon on the Chicago Board of Trade. Futures are down 16 percent this year. Gasoline for November delivery rose 4.38 cents, or 1.7 percent, to $2.6309 a gallon on the New York Mercantile Exchange . The contract covers reformulated gasoline, made to be blended with ethanol before delivery to filling stations. […]