Impact of living mulch on arthropod fauna: analysis of pest and beneficial dynamics on organic cauliflower (Brassica oleracea L. var. botrytis) in different European scenarios

The effect of a ‘cover crop–vegetable cash crop’ intercropping system on arthropod dynamics and biodiversity, was investigated in four different European countries (Italy, Denmark, Germany, and Slovenia), by means of two-seasonal experiments. The soil arthropod fauna was used to compare the ecosystem services of living mulched systems with sole crop ones. The living mulch (LM) technique did not affect the infestation of cabbage caterpillar Pieris spp., showing no detrimental effect of this technique on this key pest of cabbage. In Denmark, aphid populations were higher in the sole crop system than in the LM system. In Italy, a very high level of larval parasitization was detected and in 1 year the percentage of parasitization was higher in LM (88%) than in sole crop (63%). Overall, the LM positively affected the activity density of Carabid beetles, also increasing diversity and evenness of species (Italy and Slovenia) or activity density of some taxa (Slovenia and Denmark). Our results indicate a general positive influence of LM techniques on arthropods in plant/soil systems, as shown by a high level of soil biodiversity and a general lack of negative effects on the density of canopy pests.