"Fungal foliar diseases caused by Alternaria dauci and Cercospora carotae occur annually on carrots. Our goal was to update the disease management tactics by: 1) Testing OMRI-approved and conventional fungicides and 2) Evaluating TOM-CAST. Trials were conducted in 2015 and 2016. Disease severity was visually assessed weekly using the Horsfall-Barratt scale and a petiole health scale; the area under the disease progress curve (AUDPC) was calculated for these parameters. Root yield was determined at harvest. Based on AUDPC results obtained in 2015 and 2016, the copperbased fungicides (copper hydroxide and copper hydroxide + copper oxychloride) were the only OMRI-approved products that significantly and consistently limited foliar blight. On the final assessment dates in both years, all conventional fungicides limited foliar and petiole blighting compared to the control with one exception; the propiconazole treatment in 2016 was similar to the control for petiole health. Yields differed significantly among the conventional treatments in 2016 but not in 2015. All treatments yielded significantly higher than the control except for iprodione. Treatments of pyraclostrobin + boscalid, fluxapyroxad + pyraclostrobin, and boscalid had statistically higher yields than penthiopyrad, iprodione, and propiconazole. TOM-CAST 15 and 25 DSV fungicide application schedules effectively reduced foliar blighting in 2015 under relatively light disease pressure. However, the TOM-CAST 25 DSV schedule did not adequately limit disease in 2016 when disease pressure was increased. Recently registered fungicides such as penthiopyrad and fluxapyroxad + pyraclostrobin and using TOM-CAST at the more conservative spray threshold of 15 DSV can help growers limit fungal foliar blight in years with higher disease pressure."--Page ii.
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