Introduction or stimulation? The association of Stropharia aurantiaca with bark and wood-chip mulches

Polymerase chain reaction (PCR) primers ST1 and ST2 were designed for the specific amplification of ribosomal DNA from Stropharia aurantiaca, and a nested PCR method was developed for the detection of S. aurantiaca in garden soils and mulches. The results of PCR screening of garden soils and mulches indicated that S. aurantiaca could be detected in the absence of visible fruiting bodies. The occurrence of S. aurantiaca in soil and mulch was investigated to determine if the application of wood-chip mulch resulted in the introduction of the fungus or the stimulation of an already present population.