Technical Abstract: Carrot cultivars grown in New York were evaluated for susceptibility to the fungal leaf blight pathogens Alternaria dauci (1999) and Cercospora carotae (2000 to 2003)in an experimental field under continuous carrot cultivation since 1996. Replicated plots were established in a randomized complete block design. Plants were rated for disease incidence and severity at regular intervals. Cultivar susceptibility was ranked based on the area under the disease progress curve. An IPM program for carrot leaf blights conducted in growers’ fields provided the opportunity to determine the impact susceptibility had on date fungicide threshold was reached. Bolero, Carson, Calgary, Ithaca, and Fullback were resistant to Alternaria. Bolero, Carson, and Bergen were resistant to Cercospora. Fontana was most susceptible to both leaf blights. In grower fields, more resistant cultivars reached the 25% disease incidence threshold later than more susceptible counterparts. Carrot cultivar susceptibility was incorporated into an IPM program for these diseases.