Foliar Leaf Spots of Viburnum during Nursery Production in Florida: Research and Fungicide Efficacies

Viburnum sp. is an important woody ornamental crop for nursery growers in Florida. Around 2014, growers indicated that common labeled fungicides targeting downy mildew failed to provide acceptable levels of disease management. Through a research grant from the Florida Nursery, Growers and Landscape Association, UF/IFAS researchers and UF/IFAS Extension Hillsborough County agents conducted studies to determine fungicide efficacy of oomycete fungicides to help nursery professionals produce and maintain a healthy viburnum crop. Written by Shawn Steed, Wael Elwakil, Marissa Cassaway, and Gary Vallad, and published by the UF/IFAS Department of Environmental Horticulture, December 2025.