Crown Gall Tumor on Grapevine (IMAGE) University of Würzburg Caption Visible to the untrained eye upon closer inspection only: a crown gall tumor is on a vine. Credit (Picture: Hanna Faist) Usage Restrictions None 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.