The current study aimed to evaluate the efficacy of the biofungicide Bacillus subtilis Ch-13 in the suppression of natural infection of white button mushrooms (Agaricus bisporus) with Hypomyces perniciosus (causal agent of wet bubble disease), as well as its impact on mushroom yield in industrial-scale cultivation. The biofungicide B. subtilis Ch-13 was applied at a total concentration of 60 ml per m2 of casing layer in two different procedures ? using either three (30 + 2 ? 15 ml m-2) or two split doses (2 ? 30 ml m-2) ? and then its effects were compared to those of the fungicide prochloraz applied at the standard application rate. The efficacy of the biofungicide was significantly higher when applied in three split doses (29.7%), than in two (15.7%). Though the efficacy of B. subtilis Ch-13 (?30%) against H. perniciosus was low in comparison to that of prochloraz (?68%), B. subtilis Ch-13 slightly reduced wet bubble symptoms. Furthermore, the highest increase in mushroom yield was achieved when B. subtilis Ch-13 was applied in three split doses (14%), rather than two (2%), compared to the untreated control. In comparison to prochloraz, three and two split applications of B. subtilis Ch-13 enhanced mushroom yield by up to 17% and 4%, respectively. Regarding its efficacy in wet bubble disease control and augmentation of mushroom yield, B. subtilis Ch-13 was much more effective when applied in three split doses, than in two. Therefore, this study supports the application B. subtilis Ch-13 in three split doses (30 + 2 ? 15 ml m-2, on the second day and two weeks after casing, and after the first fruiting flush, respectively) to suppress H. perniciosus and increase mushroom yield.
Potočnik et al. (Wed,) studied this question.