Corn prices used to move up and down with the weather, livestock inventories and exports, but the federal government’s biofuels policy has linked corn prices to energy prices. For the past 15 months, there’s been a strong correlation between corn prices and ethanol prices. Since ethanol prices follow gasoline prices, it’s not surprising that a $2.50-per-gallon drop in gasoline prices since early July has dropped corn prices to less than half of this summer’s peak. So, where will corn prices head in 2009?  Keep an eye on crude-oil futures.