Factors Affecting the Differentiation of Resistant Faba Bean Plants after Inoculation with Sclerotinia trifoliorum

Faba bean (Vicia faba L.) plants 3, 4, 5 and 6 weeks old were inoculated at different internodes by carrot root pieces colonized by the fungus Sclerotinia trifoliorum Eriks. The plants were left in the growth chamber for 72 h. In addition, eight faba bean cultivars, 4 weeks old, were inoculated by the same inoculum which was left on the stems for various lengths of time. When the inoculum was removed, the plants were scored for disease severity. The highest disease seventy was on the youngest tissues inoculated. Susceptible and partially-resistant cul-tivars could be differentiated effectively when the inoculum was removed 48 to 72 hours after the inoculation.