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 85 crop safety trials on 16 environmental horticulture plant species or genera between 2018 and 2023. In these trials, 15 of 16 species or genera exhibited no or minimal injury. Twelve species or genera exhibited no injury in at least 3 trials. One genera, Rosa sp, exhibited moderate injury in one trial after two consecutive biweekly foliar applications of Picarbutrazox SC. The remaining three species or genera exhibited no or minimal injury in the limited number of trials (one or two) for each crop.