Résumé
Phytoseiid mite densities and diversity were surveyed on 16 plant species in two arboreta in the South of France. Samplings in these two arboreta were carried out on 5 trees of the same plant species twice a month during 4 months. Within the same arbouretum, densities were not significantly different within the same plant between the 5 replicated realised. However, differences in phytoseiid mite densities and diversity were seen between the plants species within each of the two arboreta. In order to determine the factors affecting these differences, foliar characteristics (trichome and domatia densities, domatia structure, pilosity of the vein axils, leaf surface) were evaluated. Multi-factorial analysis shows relationships between some of these parameters, especially domatia density and structure and pilosity on vein axils, and phytoseiid mite densities. These results are different from previous observations, as they minimise the importance of leaf trichomes on limb. This could be due to phytoseiid mite species considered and especially to their size, larger phytoseiids being probably less able to colonise high pilose leaves. Mite densities and diversity were also different for same plants located in the 2 arboreta. Kampimo-dromus aberrans was the main species occurring in the aboretum 2 and is absent in the first one while Typhlodromus exhilaratus was the main species in the arboretum 1 but not in arboretum 2. different factors, as ecological factors like surronding vegetation and environment, plant community successions, soil characteristics affecting plant communities and plant physiology, could have determined abundance and diversity of phytoseiid mites