Characterizing Sources of Resistance to Phytophthora Blight of Pepper Caused by Phytophthora capsici in North Carolina

Phytophthora blight, caused by Phytophthora capsici, is an important disease of peppers in the United States and worldwide. P. capsici causes crown, root, and fruit rot as well as foliar lesions in peppers. Field trials were conducted in 2015 and 2016 to evaluate 32 commercial and experimental pepper cultivars against a mixed-isolate inoculum in North Carolina. Cultivars Martha-R and Meeting were classified as highly resistant to P. capsici, and Paladin was classified as resistant. Intermediate resistance to P. capsici in the field was observed with Fabuloso, Revolution, Vanguard, Archimedes, Aristotle, Ebano-R, and Declaration. Greenhouse experiments were conducted to determine the response of 48 pepper cultivars when inoculated individually with two isolates from North Carolina and an isolate from Michigan. Isolates exhibited different levels of virulence in pepper cultivars screened for resistance. Landraces CM334 and Fidel as well as the cultivars Martha-R, Meeting, and Intruder were categorized as highly resistant or resistant to the three isolates tested. Overall, highly resistant cultivars tended to respond similarly to field mix inoculations and greenhouse single isolate inoculations.