Fusarium levels in grain harvested from New Zealand wheat and barley crops in 2000

Samples of grain from 40 New Zealand wheat and barley crops harvested in 2000 were assayed for Fusarium infection. Grain from all crops was infected, and Fusarium incidence ranged from 3 to 52% of grains infected, with a mean of 14%. Incidence of Fusarium was higher in spring wheat than in autumn wheat or spring barley. The highest level of infection (52% grains infected) was found in Otane wheat (highly susceptible to Fusarium head blight) sown into a paddock after maize, although there were no general effects of cropping history on grain infection. Levels were lower when residues of the previous crop were burned rather than baled or incorporated. Infection levels varied between cultivars, corresponding to the variability in susceptibility to Fusarium head blight.