Etiological and epidemiological concerns about Pepper root and lower stem rot caused by Fusarium oxysporum f. sp radicis-capsici f. sp nova

摘要

Inoculum sources of Fusarium oxysporum f. sp. radicis-capsici and host susceptibility were studied in commercial pepper cultivars and related Capsicum spp. The pathogen could not be identified in irrigation water or in the microbiologically enriched potting medium, or associated with the seeds used in the nursery where the disease was initially reported in Spain. Although the disease was asymptomatic on older pepper plants, pathogenic strains could still be isolated from the soil of those greenhouses where the disease had been previously observed. Host susceptibility in commercial pepper cultivars and related Capsicum spp. was studied. All pepper cultivars tested (n = 19), including three rootstocks, developed symptoms when inoculated with Fusarium oxysporum f. sp. radicis-capsici. Three C. baccatum accessions and one C. annuum accession exhibited resistance, whereas two C. chinense accessions showed only partial resistance. The disease symptoms could not be distinguished from those caused by one F. oxysporum f. sp. capsici isolate, and molecular analysis also showed identical tef sequences for both formae speciales.