The price of corn is falling as weather conditions remain favorable for the crop.
Corn for July delivery dropped 1.5 cents, or 0.3 percent, to $4.43 a bushel.
The price of the grain has plunged in the last two months as rains have been light and temperatures remained moderate. The U.S. Department of Agriculture is forecasting a record crop this year.
In other trading of agricultural products, wheat and soy beans also fell.
Most metals climbed, led by platinum. Gold and silver also ended the day higher.
The price of oil fell 14 cents, or 0.1 percent, to $106.03 as traders monitored the insurgency roiling Iraq for any signs it could affect the country's oil production and exports.