Apples Used to Test Koch's Postulates (IMAGE) American Phytopathological Society Caption Representative potted Abies fraseri and inoculated apples used to test Koch's Postulates. Credit De-Wei Li, Neil P. Schultes, James A. LaMondia, and Richard S. Cowles 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.