Influence of cropping system on Fusarium head blight and mycotoxin levels in winter wheat

In this study, we investigated the effects of various wheat cropping systems on Fusarium head blight severity and mycotoxin (deoxynivalenol, nivalenol, zearalenone) levels. We investigated four wheat-cropping systems: a conventional system, an integrated system, a direct drilling system and an organic system, in fields with natural contamination. The study was carried out over three 1-year periods: 1999-2000, 2000-2001 and 2001-2002. The severity of Fusarium head blight and toxin levels differed considerably between years, reflecting climatic effects. In a given year, the severity of Fusarium head blight also differed between cropping systems, with the most severe disease observed in the direct drilling and conventional system plots in 2000. The level of grain contamination by mycotoxins therefore depends on both climate and cropping system. Mycotoxin levels were highest in the year with the highest disease severity: 2000. Contamination levels were highest with the direct drilling system. We were unable to rank the organic and conventional systems, because neither was consistently more contaminated than the other. Moreover, no clear relationship was found between disease severity and levels of contamination with deoxynivalenol, nivalenol or zearalenone under conditions of natural contamination. (C) 2003 Elsevier Ltd. All rights reserved.