Picarbutrazox is a novel fungicide with a new mode of action being developed by Nisso America for the control of oomycete diseases such as Bremia, Peronospora, Pseudoperonospora, Phytophthora , Pythium and Phytopythium. The IR-4 Project completed 46 crop safety trials on 14 environmental horticulture plant species or genera between 2018 and 2021. In these trials, 13 of 14 species or genera exhibited no or minimal injury. Three species or genera (Impatiens hawkeri, Impatiens walleriana and Rudbeckia hirta) exhibited no injury in 3 trials. One genera, Rosa sp, exhibited moderate injury in one trial after two consecutive biweekly foliar applications of Picarbutrazox SC. The remaining 10 species or genera exhibited no or minimal injury in the limited number of trials (one or two) for each crop.