Regev, a New Hybrid Fungicide for Control of Cercospora Leaf Spot on Sugar Beet

Cercospora leaf spot (CLS) is one of the most yield-limiting foliar diseases of sugar beet in the United States. Standard practices to control this disease include selection of tolerant varieties, crop rotations, and reliance on fungicides. However, genetic resistance still requires some fungicides for acceptable control under high disease pressure, and there are only a limited number of fungicides registered for control of this disease. Regev is a newly registered hybrid fungicide for sugar beet disease control that contains eight biological active ingredients from tea tree oil (TTO) and one active ingredient from the synthetic fungicide difenoconazole. TTO provides a new and unique mode of activity against both fungal and bacterial plant pathogens, and it has a low resistance risk. Eight trials were conducted to evaluate Regev for efficacy against Cercospora leafspot and sugar beet yield and quality benefits in Minnesota and Michigan. Five of the trials had slightly different treatments, with the primary goal of allowing trialists to conduct trials with treatments that were appropriate for their locations. However, one of the trials at the Northwest Research and Outreach Center (NWROC) of the University of Minnesota in Crookston,MN, was conducted three times over the years 2021, 2022, and 2023. Across the eight trials, spray programs that included Regev provided control of Cercospora leaf spot equal to standard fungicide programs.