Empty shelves where eggs should be at a Whole Foods Market in Washington, D.C. The store blames increased demand for organic eggs. Dan Charles/NPR hide caption

itoggle caption Dan Charles/NPR

A corn field is shrouded in mist at sunrise in rural Springfield, Neb. Nati Harnik/AP hide caption

itoggle caption Nati Harnik/AP

President Obama and Agriculture Secretary Tom Vilsack (second from right) inspect drought-damaged corn on the McIntosh farm in Missouri Valley, Iowa. Carolyn Kaster/AP hide caption

itoggle caption Carolyn Kaster/AP