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POSTERS: Chemical control

Quantifying Control Efficacy of Fungicides Commonly Applied for Potato Early Blight Management
S.K Reddy Yellareddygari - North Dakota State University. Julie Pasche- Dept of Plant Pathology, North Dakota State University, Neil Gudmestad- Department of Plant Pathology, North Dakota State University, Raymond Taylor- North Dakota State University

Early blight is economically important foliar disease of potato. Due to lack of resistant potato cultivars, fungicides are applied extensively to obtain adequate control of this disease. To manage early blight, standard protectant fungicides and single-site-mode of action “specialty” fungicides are commonly applied, either alone or incorporated into a fungicide rotation program. Control efficacy at two crop growth stages and the overall tuber yield response to standard and specialty were assessed using network meta-analytic models. Control efficacy of both fungicides was moderate to very high (>30 to 75%) compared to the nontreated check. For both potato growth stages, specialty fungicides performed better than standard protectant fungicides. Furthermore, control efficacy of both fungicides was higher (3-9%) at late bulking and tuber maturation when compared to early bulking crop growth stage. Specialty fungicide programs increased overall tuber yields by 4% and 9% over standard fungicides and nontreated check, respectively. Based on the meta-analysis more precise fungicide use recommendations and fungicide programs can be developed for early blight management.