Entomopathogenic soil fungus in Swiss potato fields

Wireworms, the larvae of elaterid beetles, belong to the most important pests of the Swiss potato production. Chemical control is much contested. Therefore, it is strongly desired to develop a biological control method. The entomopathogenic soil fungus Metarhizium anisopliae seems to be a good candidate. In order to get information on the distribution of this fungus in arable land 30 fields, which are part of a project on potato quality, were selected to be analyzed for presence and density of M. anisopliae. 10 fields each belonged to the three different production systems «organic farming», «integrated production» and «production with ecological requirements». Furthermore, the data were compared with data on crop rotation (two years sawn meadow before potato versus arable crop) and pesticide use.The data revealed that M. anisopliae was present in all fields. No differences were found between the three production systems in regard to fungus density and fungus presence in the soil samples. Furthermore, no influence of the crop rotation or of the pesticide use was found. It is assumed that M. anisopliae is able to resist the applied agricultural practices or to recover rapidly. These characteristics make this fungus to a suitable candidate for wireworm control.