The US Department of Agriculture has lowered its forecasts for corn production and predicted sharp price rises, due to a drought and heatwave destroying much of the country's crop.
The department on Friday lowered its corn yield forecast by 22.6 bushels per acre to 123.4 bushels.
It now expects that this year's corn yield - the amount produced per acre - will be the lowest since 1995-96.
The department predicts farm prices for corn will average $US7.50-8.90 a bushel. In July it predicted $US5.40-6.40.
The latest forecasts from the department suggest that corn production in 2012-13 will be 10.8 billion bushels, some 2.2 billion less than predicted last month and the lowest since 2006-07.
The United States is the world's biggest producer of corn, soybeans and wheat.
The United Nations Food and Agriculture Organization has warned that the dry spells in the Midwest could lead to higher food prices.
The BBC reports corn is a staple food in many countries. It is also used in animal feed and to produce biofuel ethanol.