Studies on the toxic substance in the infected cereals. VIII. On the toxigenic fusaria invading barley and wheat in the southern Japan.

Reperesentative fungi were isolated from preharvested and freshly harvested barley and wheat grains of eleven prefectures located in the Southern Japan, and studied on ability to produce several Fusaria-toxins in culture media and rice grains. Predominant types of 106 isolates belonged to the species Fusarium graminearum. Incidences of fungal isolates revealing lethal toxicity for mouse and skin necrotization for rats were 22.6% and 34.9%, respectively. The occurrence of Fusaria-toxin producing strains was 39.6% for 12, 13-epoxytrichothecenes, 34.9% for butenolide (4-acetamido-4-hydroxy-2-butenic acid γ-lactone) and 16.3% for zearalenone [6- (10-hydroxy-6-oxo-trans-1-undecenyl) -β-resorcylic acid-lactone], respectively. About half of these toxigenic strains showed the ability to produce two or more mycotoxins simultaneously. The majority of 12, 13-epoxytrichothecene-producing strains of F. graminearum metabolized either deoxynivalenols or nivalenols. These data provide conclusive evidence for the infection of field barley and wheat of the Southern Japan by different strains of F. graminearum which produced either deoxynivalenols or nivalenols.