This standard describes the conduct of trials for the efficacy evaluation of fungicides against fungal diseases of cultivated button mushrooms (Agaricus bisporus) in controlled conditions from spawning through to the crop production phase. This standard can be adapted for use on other cultivated mushrooms [e.g. Agaricus bitorquis, oyster mushroom (Pleurotus spp.) or shiitake (Lentinus edodes)]. If a different type of compost (growth medium) is used, this should be taken into consideration.