Old Corn (IMAGE) Penn State Caption Examining 1,000-year-old corn cobs from an ancient ruin in Arizona, researchers found a previously unknown virus -- the oldest plant virus ever reported. Credit Roossinck Laboratory, Penn State Usage Restrictions Non commercial use only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.