Assessment of growth was made daily during the incubation period, with wheat grain cultures being examined using a binocular magnifier (10). Two diameters of the growing colonies were measured at right angles to each other until the colony reached the edge of the plate. The radii of the colonies were plotted against time, and a linear regression applied to obtain the growth rate as the slope of the line. Three complete Petri plate cultures per treatment were destructively sampled after 7, 14, 21, 28, 35, 42 or 49 days of incubation, dried at 50 -C for 24 h and stored at 20 -C until DON analysis was carried out.