Fusarium mycotoxin content and Fusarium species presence in Czech organic and conventional wheat

Abstract

Deoxynivalenol and zearalenone content and the presence of Fusarium species in organically and conventionally grown wheat harvested in the Czech Republic during 2015-2017 were studied. Mycotoxin contamination was compared using two approaches. The first was based on samples taken from randomly selected farms in individual regions of the Czech Republic, both organic (154 samples) and conventional (330 samples). In the second approach, a sample set of conventional wheat compatible with organic one was formed, with samples paired according to the preceding crop and region of harvest. Using the first approach, mycotoxins were shown to be higher in conventional wheat; however, there was no difference in mycotoxin contamination between organic and conventional wheat using the second approach. Eight wheat samples with mycotoxin content above the EU limits were found, seven for deoxynivalenol (2.1%) and one for zearalenone (0.3%), all of them originated from conventional farming system. Six of them had maize as the preceding crop. The presence of five Fusarium species (Fusarium avenaceum, Fusarium culmorum, Fusarium graminearum, Fusarium poae and Fusarium sporotrichioides) was compared for the compatible wheat sample sets (second approach). The predominant species were found to be F. poae and F. graminearum in both the organic and conventional wheat. Harvest year significantly influenced both the occurrence of the main Fusarium species and the level of mycotoxin contamination. The study confirmed that (a) organic farming system was able to keep mycotoxin contamination of wheat at a low level, (b) in studies on the significance of organic/conventional agricultural practice on mycotoxin levels in cereals, it is important to pay attention to common production and environmental variables.