Reaction of seedling roots of 14 crop species to Fusarium graminearum fromwheat heads

To increase our understanding of the epidemiology of fusarium head blight o f wheat and barley, a study was conducted under controlled conditions to de termine whether Fusarium graminearum Schwabe from wheat can cause seedling blight or root rot in various crop species. Inoculum of F. graminearum, con sisting of a wheat floret infected with the pathogen, was placed adjacent t o surface-sterilized seed of each crop in a sterile potting mix. Wheat, bar ley, oat, rye, triticale, canaryseed, flax, canola (Brassica napus L. and B rassica rapa L.), mustard, bean, field pea, lentil, and chickpea were inclu ded in the study. Seedling emergence and root rot severity were scored at 3 -4 weeks after seeding. The effect of temperature on seedling blight severi ty was also tested in barley cv. Brier. Inoculation reduced emergence in al l crops, except canola, mustard, and field pea, and increased root rot seve rity in most crops. Emergence of seedlings was not affected at the lowest t emperature (10:5 degreesC day:night) and no root infection occurred. Howeve r, as the temperature increased from 10 to 30 degreesC, seedling emergence and establishment were reduced and root rot severity increased. Infection o f roots, crowns, and seedlings of the crops grown in rotation with wheat in dicates that these crops may act as alternative hosts to F. graminearum.