Control of dry bubble disease (Lecanicillium fungicola) in button mushroom (Agaricus bisporus) by spent mushroom substrate tea

Dry bubble (caused by Lecanicillium fungicola) is a widespread disease of button mushroom. The objective of the experiments was to determine the efficacy of compost teas made from spent mushroom substrate (SMS) as a biocontrol method against the disease. All SMS teas produced in this study significantly inhibited (100 %) the in vitro mycelial growth of L. fungicola, whereas the fungicide prochloraz at 50 ppm inhibited growth by 91 %. The in vivo effectiveness of two SMS aerated teas, one with mineral soil (MS) and the other with peat (TPT), was evaluated in two mushroom cropping trials inoculated with L. fungicola. The results demonstrated that the most effective treatments were those with TPT applied close to harvest and/or those with the greatest number of applications. The most efficacious treatments were TPT treatments (reducing disease by 34 to 73 % in the two trials, compared to the inoculated control). In contrast, prochloraz reduced disease by 7 % and 4 % in the two trials, compared to the control. These results suggest that dry bubble disease can be controlled by the use of spent mushroom substrate teas.