VARIATION IN PATHOGENICITY ON POTATO-TUBERS AND SENSITIVITY TO THIABENDAZOLE OF THE DRY ROT FUNGUS FUSARIUM-AVENACEUM

The majority of isolates of Fusarium avenaceum caused dry rot on potat o tubers: many were as pathogenic as F. coeruleum. Pathogenicity of F. avenaceum was not related to the plant species from which the isolate s originated. Tubers of potato cv. Cara were more susceptible than tho se of cvs Romano or Maris Piper. Temperature (5-15 degrees C) had no e ffect on lesion depth but lesions tended to be slightly wider at the l owest temperature. Two isolates (of 61) from wheat and white lupin had a moderate level of resistance to thiabendazole. The results are disc ussed in relation to the control of dry rot in stored potato tubers.