Brown Blotch Disease (IMAGE) Proceedings of the National Academy of Sciences Caption Symptoms of brown blotch disease in white button mushroom Agaricus bisporus caused by Pseudomonas tolaasii (left) can be prevented by addition of the helper bacteria Mycetocola tolaasinivorans (right). Credit Image credit: Ron Hermenau. 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.