The fungicide was marketed for use against "Phytophthora infestans". Berkeley labelled the fungus he found "Botrytis infestans," now known as "Phytophthora infestans". The Great Irish Famine was caused by the mysterious fungus, Phytophthora infestans. Compost, soil or potting medium can be heat-treated to kill oomycetes such as "Phytophthora infestans". The most well-known example of "Peronosporomycetes" is "Phytophthora infestans". He studied the pathogen "Phytophthora infestans" (formerly "Peronospora infestans") and elucidated its life cycle.