BROWN DISCOLORATION OF MUSHROOMS CAUSED BY PSEUDOMONAS-AGARICI

Incidence of brown-discoloured mushrooms, differing from brown blotch disease caused by Pseudomonas tolaasii, has increased in the Netherlan ds and been responsible for considerable economic losses. A comparativ e SEM-study of diseased tissue revealed that hyphae were collapsed and covered with a plaque in which numerous bacteria were embedded. The p redominant bacterium identified was Pseudomonas agarici. Both our isol ated P. agarici strain and the type strain P. agarici LMG 2112 caused brown discolouration of mushrooms after spraying with bacterial suspen sions. Drippy-gill symptoms were not observed.