Vineyard colonisation by predaceous mites (Acari: Phytoseiidae) living in surrounding vegetation

The aim of this work was to study the colonization by phytoseiid mites living in neighboring uncultivated areas of a vineyard in the South of France. The experimental vine plot was co-planted with Sorbus domestica in a framework of agroforestery investigations. This study was carried out during 3 years (1999, 2000 and 2001) in a vine plot planted in 1997. Phytoseiid mites have been collected in cultivated and uncultivated areas surrounding the experimental plot. Dispersal of these mites into the plot has been studied using aerial traps. Phytoseiid mites have been observed in the surrounding cultivated and uncultivated areas. However, densities were quite low. Phytoseiid mites dispersed into the experimental plot, but low densi ties of mites have been caught. Nevertheless, these densities seemed to be sufficient to provide efficient biological control against phytophagous mites. Typhlodromus exhilaratus was the main species trapped. This species was also the main phytoseiid mite collected in the experimental vine field and on S. domestica trees. Densities of mites in the vine field have increased during the three years. Phytoseiid mites seemed to have successfully colonized the experimental vine plot, but Kampimodromus aberrans, the species usually collected in vineyards of South of France, was not the main species observed in this case. The reasons of this colonization process is discussed here