Phytophthora blight of pepper: Screening for disease resistance

No difference in plant mortality occurred when either Blue Star (highly susceptible) or PI 201234 (highly resistant) was inoculated with four isolates of Phytophthora capsici. One isolate caused more plant mortality on Szechwan (moderately susceptible) than the other isolates. No symptoms were observed on PI 201234 when inoculated with 10⁵ zoospores/ml; Szechwan wilted at 10⁵zoospores/ml. Blue Star plants died at 10⁵ zoospores/ml and wilted at 10² zoospores/ml. When inoculated at different plant ages, PI 201234 did not wilt, however Blue Star wilted and died at all ages tested. Younger and older plants of Szechwan had less disease than plants of intermediate age. Two new sources of highly resistant genotypes are reported.