Researchers discovered that two types of bacteria (Ewingella americana and Cedecea neteri) causing diseases in oyster mushrooms (Pleurotus pulmonarius) produce harmful volatile compounds. These airborne toxins, especially one called 2,4-di-tert-butylphenol, can damage mushroom tissue and stop mushroom growth at very low concentrations. This is the first study showing that these bacterial volatiles are important factors in mushroom disease, which could help farmers develop better ways to detect and prevent these infections.