Effects of cropping systems on food and feed contamination by Fusarium and Aspergillus mycotoxins

Abstract

Fungal species belonging to the Fusarium and Aspergillus genera are the main culprits of field contamination of agricultural commodities by mycotoxins. The toxicological consequences of such contaminations are currently managed through adaptations to cropping systems. Due to large gaps in the knowledge regarding the production of mycotoxins themselves, most strategies aim at minimizing fungal infection risks. For both Fusarium and Aspergillus, cultural techniques to inhibit survival of the innoculum, such as the use of uncontaminated seeds and crop succession management, as well as crop residue treatment for Fusarium infections, are crucial action levers. For both genera, infection may be avoided by moving the crop sowing date, and a lower crop density can attenuate fungal attacks on the crop. In contrast, attenuation via management of nitrogen nutrition or water status are more complex, as different pathosystems react differently to the nutritional status of plants. Similarly, chemical protection should be considered on a case-by-case basis, as its effects on fungal communities vary. Finally, selection of mycotoxin-resistant varieties, most notably in cereals and particularly wheat, has met with higher success for Fusarium than for Aspergillus diseases. These techniques can only function as part of a coherent combination of agricultural practices, the effects of which on mycotoxin accumulation in interaction with climate effects are still poorly understood. Nevertheless, at the present level of knowledge, organic agriculture systems appear to be similarly or less affected than conventional systems.