Ripe Tomato with Bacterial Speck Disease (image) Boyce Thompson Institute Share Print E-Mail Caption Bacterial speck disease creates unattractive black spots on a ripe tomato, making it unmarketable. The disease is caused by the bacterium Pseudomonas syringae pv. tomato. Credit Gregory Martin Usage Restrictions With credit to Gregory Martin Share Print E-Mail 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.