Efficacy of Mancozeb, Captan, Copper, and Fluoxapiprolin for Control of Black Rot and Downy Mildew of Grape, 2026

Mancozeb, an older broad-spectrum fungicide, faces regulatory pressure. If grapes are removed from the mancozeb label, replacement fungicides may be needed to manage multiple grape diseases, including black rot and downy mildew, caused by Phyllosticta spp. and Plasmopara viticola , respectively. In 2026, Captan 4L (captan) and Kocide 3000 (copper) were evaluated for control of black rot and downy mildew, while Xivana Prime (fluoxapiprolin) was evaluated only for downy mildew control. Treatments were applied to a ‘Camminare Noir’ American grape hybrid in Watkinsville, GA, U.S.A. Results from this trial will help growers determine which products are best for future disease-management strategies.