Relationships among toxigenic fusaria, their associated toxins and climate were examined for cereal crops grown in diverse locales. Fusarium sporotrichioides, F. poae, F. semitectum, F. equiseti, F. culmorum, F. graminearum, F. moniliforme, F. subglutinans and F. oxysporum were examined. F. culmorum occurred in cool northern Europe as the producer of deoxynivalenol and zearalenone, but was replaced in this role by F. graminearum in the warmer climates of southern Ontario, Canada, in the north central U.S.A., and mid and southern Japan.