Fusarium species colonizing spears and forming mycotoxins in field samples of asparagus from Germany and Poland

The occurrence of Fusarium spp. and associated mycotoxins in asparagus spears was evaluated in Poland in 2002 and 2003 and in Germany in 2002. Spears of two cultivars, Eposs and Gijnlim, were collected from two locations in Poland, Swidwowiec and Poznan, on sandy and sandy loam soil, respectively. Fusarium oxysporum and F. proliferatum were detected at an average incidence of 38.3% and 15.8% in the spear sections sampled, respectively. In stands of 11 (tested) cultivars of asparagus sampled in Germany on sandy soil, the same species dominated, however, they were less frequent than in Poland (26.6% and 5.6% of the spears infected with F. oxysporum and F. proliferatum, respectively). Chemical analyses revealed that fumonisin B-1 (FB1) and moniliformin (MON) were present in some of the spears sampled in Poland. FB1 was not found and MON was not assessed in spears sampled in Germany in 2002, but F. proliferatum was able to form the toxin in vitro in the range from 101.4 up to 205.8 mu g/kg maize kernel substrate. Asparagus samples in Poland contained FB1 at up to 5.6 mu g/kg spear fresh weight. The highest MON concentration (1350 mu g/kg) was detected in cultivar Eposs in Marcelin, Poland, in 2002. MON and FB1 were found in spears infected by both F. oxysporum and F. proliferatum, however, only the latter fungus was able to synthesize both toxins.