Toxigenic Fusarium species of Liseola Section in pre-harvest maize ear rot, and associated mycotoxins in Slovakia

The occurrence of Fusarium species of Liseola section and related toxins was investigated for two years (1996 and 1998) on maize ear rot samples collected in the most important areas for maize growing in Slovakia. The species most frequently isolated was F. verticillioides, followed by F. proliferatum in 1996 and F. subglutinans in 1998. Most of the strains belonged to mating populations A, D, and E of the teleomorph Gibberella fujikuroi. Fusarium graminearum was also frequently recovered in both the years of investigations. Toxin analysis of maize ears showed that most of the samples (21 out of 22) were contaminated with at least one toxin. In particular, the concentration of fumonisin B1, and fumonisin 2 was up to 26.9 and 5.1 ìg g-1, respectively in 1996, and up to 12.1 and 6.3 ìg g-1, respectively in 1998. Beauvericin was detected only in one sample in 1996. Seven samples in 1996 were contaminated by fusaproliferin up to 8.2 ìg g-1, but just traces of the toxin were found in one sample in 1998. All 29 strains of F. verticillioides, two of three strains of F. proliferatum and none of eight F. subglutinans strains isolated from samples produced fumonisin B1 in culture on whole maize kernels (0.1–5646 and 940–1200 ìug g-1, respectively). Two strains of F. subglutinans and two of F. proliferatum produced beauvericin (up to 65 and 70 ìg g-1, respectively). Ten strains of F. verticillioides produced beauvericin: 9 strains produced a low amount (up to 3 ìg g-1), while only one of them produced a high level of toxin (375 ìg g-1). Fusaproliferin was produced by two F. proliferatum strains (220 and 370 ìg g-1), by seven F. subglutinans (20–1335 ìg g-1) and by three F. verticillioides (10–35 ìg g- 1). This is the first report on fusaproliferin production by F. verticillioides, although at low level.