Kampimodromus aberrans is a predatory mite species present in vineyards of South of France and also in uncultivated areas, from where great densities disperse into the neighbouring vine fields, mainly by aerial means. In order to determine the origin of migrants in an experimental vine plot, a molecular study using RAPD markers was performed. It was found that there exists genetic differentiation of populations collected in the experimental vineyard, and those collected, both from surrounding cultivated and uncultivated areas. No correlation between genetic and geographic distances was found. Thus, despite the dispersal of great densities of mites into the plot, selection pressures may affect their settlement. To determine the impact of pesticide application on mite settlement, we studied the insecticide resistance of K. aberrans populations collected in the vine field and on an oak located in a neighbouring uncultivated area. The insecticide tested, quinalphos, is the most frequently applied pesticide in the plot. High resistance levels were observed in both populations. However, at the recommended concentration, mortality rates (80 and 87 %) were quite the same for the two populations. Thus, the application of this pesticide seems not to be the major explanation of the poor settlement of migrants coming from woody areas into the plot, and other studies have to be conducted to determine other factors involved.