Dansk

Natural regulation of insects with particular focus on soil living stages and the influence of cropping system

In this work package we investigate the effects of the cropping systems on the naturally occurring populations of insect pathogenic fungi in the soil. Fungi from the genera Beauveria and Metarhizium are among the natural enemies of insect pests. Their role in the regulation of insect populations is, however, poorly understood. In addition, limited knowledge is available of the dispersal of fungal propagules in the environment and the genetic diversity of fungal populations in the field. It is the aim of this work package to provide new knowledge of these aspects within the framework of organic farming.

Fly infected by the insect pathogenic fungus Beauveria bassiana (Photo: Nicolai V. Meyling)

Our hypothesis is that the organic cropping system, especially O3, will initiate an increase in the population levels of fungi in the soil. We will investigate how the fungi are dispersed and attempt to understand their role in the natural regulation of insect populations in the field. We focus on soil living pests, in particular cabbage root flies and carrot flies. We will monitor the population levels of these pests during the project period in the different cropping systems and assess the mortality factors of the hibernating pupae. Furthermore, we wish to register which other pests are present in the systems and intend to elucidate which groups of natural enemies are contributing significantly to the natural regulation of pest populations.

Rove beetle infected by the fungus Beauveria bassiana (Photo: Nicolai V. Meyling)

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