Response of Various Cultivars of Cucumber to Different Isolates of Pseudoperonospora cubensis (Berk et Curt.) Rostow Under Artificial Epiphytotic Conditions

Abstract

This study was conducted in the Department of Plant Pathology, University of Agriculture, Peshawar, during the 2011 growing season to assess the response of various cucumber cultivars to different isolates of the downy mildew pathogen Pseudoperonospora cubensis under artificial epiphytotic conditions. Five cucumber cultivars (Desi, Long Green, F1 Hybrid, Dollar, and Khyber) were evaluated for their susceptibility to four distinct isolates of P. cubensis. Statistical analysis revealed significant differences (p < 0.05) among cultivars, isolates, and their interactions compared with the control treatment. The F1 Hybrid and Dollar F1 cultivars exhibited the lowest disease severity, whereas isolate 4 induced the highest level of infection. In contrast, control plants demonstrated comparatively lower disease severity. The interaction between cultivars and pathogen isolates remained significant at both 30 and 40 days after inoculation, indicating differential host-pathogen responses under controlled conditions..