Virulence to Korean Pepper Cultivars of Isolates of Phytophthora capsici from Different Geographic Areas. Eun Su Kim, Graduate Student, Department of Agricultural Biology, Korea University, Seoul 136-701. Byung Kook Hwang, Professor, Department of Agricultural Biology, Korea University, Seoul 136-701. Plant Dis. 76:486-489. Accepted for publication 18 September 1991. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0486.

The relative virulence of 14 isolates of Phytophthora capsici from diverse geographic origins, including France, the Netherlands, Bulgaria, Italy, New Mexico, and Korea, was evaluated on 12 Korean pepper cultivars under controlled environmental conditions. No hypersensitive symptoms were observed in any of the cultivars inoculated with any of the 14 isolates. Highly significant cultivar, isolate, and cultivar × isolate effects were observed, indicating a differential host-pathogen interaction. Significant differences in virulence among the isolates tested were found but were not dependent on the country of origin. Isolate CBS 178.26, which has been maintained since 1926, was the most weakly virulent. To evaluate resistance, the soil-drench and stem-wound methods were more reliable than the foliar-inoculation method when highly virulent isolates were used. The stem-wound and foliar-spray methods were more appropriate than the soil-drench method when weakly virulent isolates were used.