Evaluation of maturity by use of pH indicators in sawdust-based cultures ofLentinula edodes

Colorimetric pH indicators were examined for their use in judging the culture maturity of sawdust-based cultures of shiitake,Lentinula edodes (Berk.) Pegler. Bromophenol blue (BPB) was the preferred indicator for judging culture maturity. Culture pH changes were detected as changes in color from bluish purple to yellow by direct spraying. The pH values of such cultures varied from 6.3 before inoculation to 4.0 during the fruiting stage. Culture maturity assessment can be used to control fruit body flush timing. Measurement of BPB staining inL. edodes sawdustbased cultures showed a good correlation with fruit body yield of the first flush. This method was concluded to be of value for detecting fruiting potential and therefore may be useful for evaluating flush timing forL. edodes cultivators using sawdust-based methods.