A Field Evaluation of Jalapeno and Non-Jalapeno Chile Pepper Resistance to Phytophthora Blight Caused by Phytophthora capsici

Phytophthora capsici is a destructive soilborne pathogen, which causes Phytophthora blight in many vegetable crops including chile pepper (Capsicum sp.). Our research was aimed at evaluating the resistance of jalapeno cultivars in field conditions and identifying the factors associated with reduction of Phytophthora blight caused by P. capsici. Six jalapeno (NuMex Orange Spice, NuMex Pumpkin Spice, NuMex Jalmundo, TAM Jalapeno, Early Jalapeno, and NuMex Vaquero) and two non-jalapeno (CM-334 and NM 6-4) cultivars were inoculated with P. capsici at the fruiting stage. Disease severity index (DSI), disease incidence (DI), and area under the disease progress curve (AUDPC) for each cultivar were measured. The most susceptible jalapeno cultivars with the highest DSI, DI, and AUDPC were NuMex Orange Spice, NuMex Jalmundo, and NuMex Pumpkin Spice, whereas the least susceptible jalapeno cultivars were Early Jalapeno, TAM Jalapeno, and NuMex Vaquero, with the lowest DSI, DI, and AUDPC. The identified jalapenos with reduced susceptibility to Phytophthora blight can be planted in infested fields, combined with other control methods, which may help in soil disinfestation by reducing the inoculum level in soil over time.