Agronomic and environmental impacts on concentrations of deoxynivalenol and fumonisin B₁ in corn across Ontario

Abstract

Relative effects of year, weather, and cultural practices on concentrations of deoxynivalenol (DON) and fumonisin B₁ (FB₁) were compared in grain that was harvested from corn fields across Ontario, Canada, from 1993 to 2000. Overall, between 59% and 88% of grain samples were contaminated with DON ≥ 0.2 μg g⁻¹ in each year of the survey. From 1997 to 2000, between 17% and 56% of samples were contaminated with FB1 = 1.0 μg g⁻¹, which is higher than first reported for fumonisins in 1993 in Ontario (9%). Deoxynivalenol and FB1 were mostly associated with corn hybrid and year-to-year effects caused by weather or geographical differences in the 8-year study. Among all cultural practices, corn hybrid was the most influential for both DON and FB1 accumulation, accounting for 25% (P < 0.0001) of the variation in both toxins across years. The effect due to year (or to weather, perhaps) accounted for 12% (P < 0.0001) of the variation in concentration of DON and 19% of the variation in FB₁. When the effects of hybrid and year were considered in the same model, 42% of the variability of both toxins was accounted for in the model. A higher incidence of DON and fumonisin was detected for corn grown after wheat than for corn after corn. These results demonstrate that predictive models for DON in corn need to include the sensitivity of corn hybrids to infection by Fusarium spp. or mycotoxin accumulation, in addition to the response caused by weather. In practice, the best chance for corn growers to reduce DON and FB₁ in harvested grain, when comparing cultural practices, is to select hybrids that are known to have more resistance to fusarium ear rots or mycotoxin accumulation than others.

Keywords:

• deoxynivalenol
• fumonisin
• corn
• tillage
• hybrid
• rotation
• weather