“…All cultivars are susceptible (Wollenweber, 1921;Gomolyako, 1930;Philipp, 1932;Beregovoy, 1939;Mujica, 1942;Vielwerth, 1949;Sprau, 1953Sprau, , 1966Noll, 1963;Anonymous, 1971;Hide, 1981;Gans et al, 1987;De Boer, 1991) although some cultivars such as Agria, Estima, Kennebec, Pentland Crown, Rosa and Sequoia appear to be particularly prone to the disease (Bonde, 1955;Manzer et al, 1964;Hughes, 1980;Kirkham, 1986;Christ, 1987;Wale, 1987;Christ & Weidner, 1988;Wastie & Stewart, 1990;Genet, 1993) and others such as Exton, Merrimack, Nooksack, Norchip, Parnassia and Ulster Lancer show some resistance (Bonde, 1955;Bjor, 1978;Hughes, 1980;Kirkham, 1986;Christ & Weidner, 1988;Wastie et al, 1988). Most cultivars, however, are very susceptible to the disease.…”