Bacterial blotch of mushrooms

These pages provide information and guidance on the symptoms, identifcation, causes and management of bacterial blotch on mushroom crops.

What is bacterial blotch?

Bacterial blotch caused by bacteria in the Pseudomonas fluorescens species complex is considered the most important disease currently faced by most major button mushroom (Agaricus bisporus) growing countries. A serious bacterial blotch infection in a crop can result in losses that can frequently exceed 30% of production.

Different species of bacteria can cause these diseases. The blotch symptoms on mushrooms, and their epidemiology on mushroom farms can vary according to the pathogenic species of Pseudomonas involved.

Conditions that favour high mushroom yield are also favourable for disease development and transmission, and therefore there is a trade-off between maximising yield and maintaining health and quality of production.

Learn about the signs and symptoms of bacterial blotch caused by the different pathogenic species of Pseudomonas. 

Find out about the methods of detection used to identify the presence of bacterial blotch and how different pathogenic species of Pseudomonas are identified. Also read about potential control methods for this challenging disease.

Authors

Dr Joana Vicente (Fera Science Ltd), Dr Ralph Noble (Microbiotech Ltd) and Professor George Salmond (University of Cambridge)