Postiva (pydiflumetofen + difenoconazole) is a new fungicide registered by Syngenta for the control of foliar diseases of environmental horticulture crops. The IR-4 Project completed 43 crop safety trials on 18 environmental horticulture plant species or genera during 2019 to 2022. In addition, crop safety data were collected during efficacy experiments. Across all crops tested, Pydiflumetofen + difenoconazole generally exhibited no or minimal negative impact. Seven crops were not injured after drench or foliar applications; while Begonia semperflorens did not display visible chlorosis or necrosis, but plants at the 4x rate were significantly shorter in one trial. For three crops, more information will be needed to determine response because outcomes have been variable from no impact to significant injury, six crops have been screened in less than three trials.