Isolation and Toxicity ofFusariumSpecies from Various Areas of Norway

Abstract
One hundred and twenty-five isolates of Fusarium were identified in ninety-five samples of soil collected from the arctic north, central and southern regions of Norway. Species were F. acuminatum (25 isolates, found in 26.3% of the 95 soil samples), F. avenaceum (28 isolates, 29.5%), F. culmorum (1 isolate, 1.1%), F. oxysporum (31 isolates, 32.6%), and F. sambucinum (40 isolates, 42.1%). The isolates were grown on a solid rice substrate, incorporated as 50% of a rodent diet and fed to rats to determine their toxicity. Sixty-four per cent of the isolates caused death and 44% of the isolates caused congestion and hemorrhage of various tissues including stomach, intestine, thymus, and hematuria in the bladder. One isolate caused uterine enlargement. All isolates caused decreased weight gain relative to the control diets. The toxicity of Fusarium isolates recovered from the soil samples was remarkable, particularly in F. oxysporum (25 out of 31 (80%) were toxic) and F. sambucinum (39/40=97%) reported for the first time.