Lower oilseed and grain prices have prompted a surge of overseas buying of U.S. crops. Corn prices have fallen to a three-year low amidst better than expected harvest reports. Recently, the U.S. De­­partment of Agriculture (USDA) re­­ported net corn sales of 1.3 million metric tons (51.2 million bushels). The bulk of the new sales are destined for unknown destinations, accounting for 428,000...