Blackwell Publishing Journal Backfiles 1879-2005
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
During routine, annual, field wilt-resistance trials of hop progeny, ‘breakdowns’ of resistance occurred in control varieties. Pot-plant pathogenicity tests of isolates from these trials, and other isolates obtained during farm surveys, confirmed the existence of apparently new strains potentially highly pathogenic to resistant cultivars. Results of the tests provided little evidence that enhanced pathogenicity was associated with specificity. The assumption of essentially host nonspecific pathogenicity was consistent with other observations on the inheritance of resistance.Highly pathogenic strains were identified among isolates from nine farms in Kent. The locations and ownership of these farms, and their wilt histories, provided strong circumstantial evidence that these strains had spread from a single focus, as did progressive wilt originally. Legislation, introduced to restrict further spread, may have been too late.
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