Survival and host range of Phytophthora capsici Leon under Karnataka conditions

Abstract

Phytophthora capsici Leonian is a destructive pathogen of sweet pepper worldwide. In this study. survival and host range of P. capsici under Karnataka conditions was studied. Slender amaranth (Amaranthus viridis), black nightshade (Solanum nigrum) and spurge (Euphorbia geniculata) were found as weed hosts for the pathogen. The pathogen was infective on fruits and leaves of watermelon, cucumber, gherkin, squash, pumpkin, ridge gourd. round melon, snake gourd and sponge gourd. On bottle gourd, it was infective on fruits while non infective on leaves and root. Bitter gourd and ash gourd were not hosts without any foliar, fruit and root infection. Among solanaceous crops, tomato, chilli and potato leaves, fruits and root were infected. On brinjal, only fruit infection was recorded. The isolate was weakly pathogenic on cruciferous vegetables cabbage and cauliflower with only leaf infection. None of the leguminous vegetable tested showed root infection. Leaf and pod infection was observed on French bean and cowpea. On malvaceous vegetable crop okra, only fruit infection was recorded. In Piperaceae crops, only leaf infection was observed on black pepper and betel vine. Eight millets tested were found non-hosts for the Kadur isolate of P. capsici. The pathogen survived up to 90 days when infected fruit was buried in soil irrespective of three soil textures: sandy loam, sandy clay and sandy clay loam. The information on survival and host range generated would help in developing disease management strategy against P. capsici in Karnataka.