Toxigenic fungi and approaches to control them

FHB-symptoms

A great challenge of agriculture today is to ensure food security while improving food safety. Agroscope experts develop effective and environmentally friendly measures against harmful fungi in grain cultivation.

Losses due to toxigenic fungi and life cycle of Fusarium graminearum

Grain cereals, such as maize and wheat are essential food and fodder crops. A wide range of harmful fungi can infect cereal crops during crop production and/or spoil the harvested products during storage. These include filamentous fungi that belong to the genera  Fusarium, Aspergillus, and Penicillium (Figure 1), which are known to produce secondary metabolites called mycotoxins that jeopardise food and feed safety. For example, Fusarium head blight (FHB) is one of the most important cereal diseases worldwide causing up to 30% direct and indirect losses due to decreased yield and severe mycotoxin contamination in wheat.

Abbildung 1
Figure 1. Seed health tests of infected maize kernels (left); Fusarium head blight symptoms in wheat (middle) and comparison between highly infected and healthy wheat grains (right).

The predominant species causing FHB is Fusarium graminearum, which survives on infected crop residues that later serve as the primary fungal inoculum in the field (Figure 2). Infection with F. graminearum results in the contamination of harvested grain with the mycotoxins deoxynivalenol (DON) and zearalenone (ZEN).

Figure 2. Life cycle of Fusarium graminearum in a maize-wheat rotation

Strategies to reduce the risk of Fusarium head blight

Our approaches to control mycotoxigenic fungi include sustainable crop protection strategies in the field:

  • prevention through adjusted crop rotations
  • innovative cropping systems (e.g. intercropping, cut-and-carry biofumigation, cover crops)
  • biological control (e.g. antagonistic fungus Clonostachys rosea) and
  • biopesticide botanicals (e.g. mustard-based).

White mustard (Sinapis alba) and oriental mustard (Brassica juncea) reduce the growth of several fungal species due to its bioactive matrices that contain glucosinolates and phenolic compounds. The promising biological control agent C. rosea antagonises F. graminearum on infected host crop residues and promotes plant resistance.

Future steps

  • Promotion of underutilised arable crops to develop crop rotations less prone to Fusarium infections
  • Implementation of innovative cropping systems and biological control strategies to improve food safety and food security
  • Economic assessment of new approaches to ensure farm profitability and food safety goals
  • Recommendations for agricultural policy makers to support innovation in  mycotoxin management
  • Evaluation of climate change scenarios which could shift the populations of mycotoxigenic species in cereals, such as other Fusarium species in cereals and Aspergillus flavus producing aflatoxins in maize
  • Formulation development for biopesticide botanicals and biological control agents to improve the stability and efficacy in the field.
  • Consideration of research results on Fusarium mycotoxins to improve the FusaProg forecasting system.

Contacts

Research group

Publications

Further Information

Icon FusaProg

FusaProg

Information system to assess the risk of Fusarium infection and DON contamination in wheat. For registered wheat plots, downloads are available for daily values and infection-risk maps as well as forecasts of DON contamination.

Examples of our approaches against FHB

Mais-weisser Senf Untersaat
Innovative cropping systems to prevent Fusarium head blight in cereals using maize-white mustard intercropping..
Brauner Senf
..and cut-and-carry biofumigation
Maisstängel Clonostachys
Biological control of F. graminearum on infected maize crop residues with the antagonistic fungus C. rosea..
Maisstängel mit Perithezien
..compared with an untreated, but infected control that shows the development of the fruiting bodies in spring