Biological control of phytopathogenic fungi by soil fauna
Agricultural production of food, feed and renewable resources requires a healthy soil. However, soil-borne pathogens may endanger quality and quantity of the crop yield. The soil biodiversity pool delivers ecosystem services, which promote the repression of pathogenic soil fungi and the degradation of mycotoxins.
Conservation tillage as a measure of agricultural soil protection promotes soil biodiversity and soil biological activity by the provision of remaining crop residues on and near the soil surface. However, this kind of residue management may increase the infection risk for cereal crops with soil-borne phytopathogenic fungi, which produce harmful mycotoxins. Fungi species of the genus Fusarium with its most frequent toxin deoxynivalenol are economically very important. In this context we follow the hypothesis: Fungivorous soil fauna mitigate the risk originating from crop residues on the soil surface. We identify and assess ecosystem services of soil fauna to answer the following questions:
(i) How do different soil fauna groups contribute to Fusarium repression and deoxynivalenol degradation?
(ii) How relevant is the interaction of different soil fauna groups in this context?
(iii) Does soil texture matter for these processes?
Field and laboratory experiments are conducted. The experiments consider different species of earthworms and fungivorous collembolans and soil nematodes. We use micro- and mesocosms, which are set up with soil, infected straw and defined densities of soil fauna in varying combinations. Compared with control units, the contents of Fusarium proteins and deoxynivalenol are quantified in soil and remaining straw for specified experimental dates.
So far, results were obtained for different earthworm species, collembolans and nematodes in field and laboratory studies. Earthworms play an important role in the control of the phytopathogenic fungi Fusarium culmorum surviving on plant residues. Furthermore, they accelerate the degradation of its mycotoxin deoxynivalenol. Compared to secondary decomposers, earthworm species belonging to primary decomposers are the drivers of these processes. Interacting collembolans and nematodes have a high impact on these processes. Soil texture is an important factor, which controls the provision of ecosystem services by soil fauna.
5.2009 - 6.2015
Project status: finished