Corn wilts in the field in Mitchelville, IA October 28, 2007. While rising demand for grain to make fuel, food and livestock feed has helped push the prices of corn and soybeans up 40% and 75%, respectively, from a year ago,  farmers in northwestern Iowa and southeastern South Dakota have found aflatoxin, a mold that can cause cancer in humans if consumed in large amounts, in their recently harvested corn, said a researcher at Iowa State University. Photo by Keith Bedford