A laboratory assay for determining pathogenicity of Phytophthora spp. to tomato

Abstract

A satisfactory method was devised for evaluating pathogenicity, under sterile conditions, of isolates of Phytophthora spp. to tomato seedlings. The radicals of tomato seedlings, grown on moist seed testing paper, were inoculated in situ with strips of agar inoculum. Elongation subsequent to inoculation and lesion length were measured to assess disease severity. The method has been found suitable in this laboratory for other root pathogens and hosts and may be of use in distinguishing resistant varieties and for race classification.