Impact of Fusarium Head Blight in Reducing the Weight of Oat Grains

Fusarium head blight (FHB or scab) is caused by the fungus Fusarium graminearum (teleomorph Gibberella zeae) and has emerged during the last few decades as one of the major threats to cereal production, with the steady increase in the incidence of this pathogen having led to severe quantitative and qualitative damage. For oats, unlike other winter cereals such as wheat or barley, there is little information regarding yield losses due to FHB. We field-evaluated 15 different oat genotypes with or without FHB on their panicles and treated or untreated with fungicide. For each genotype, 300 ripe panicles per treatment were hand harvested, individually threshed and weighed to estimate the weight of grain produced and correlate this with FHB genotype resistance. Damage caused by the disease was calculated by subtracting the observed yield from the potential yield. When untreated with fungicide, no genotype showed complete immunity to FHB but the average potential grain weight loss for the 15 oat genotypes was small (3.29%), although five genotypes did show significantly reduced grain weight when infected with FHB. Fungicide treatment significantly reduced the percentage of infected spikelets and grain weight loss for the majority of genotypes. Although the data showed relatively small grain weight losses due to FHB, there was no genotype with complete immunity to this pathogen. It appears that continuous no-tillage may influence the incidence of FHB on oats and should be carefully monitored in the field.