SEASONAL INCIDENCE AND ECOLOGY OF THE TICK IXODES-RICINUS (ACARI, IXODIDAE) ON GRAZING PASTURES IN WESTERN FRANCE

A longitudinal survey was carried out during a 2 year period in Wester n France to assess the infestation level of grazing pastures by Ixodes ricinus ticks. Four farms were visited once a month and each of the g razing pastures was sampled in the centre and at the border using the blanket dragging method. A total of 3562 I. ricinus (34 adults, 900 ny mphs and 2628 larvae) were collected and the infestation was significa ntly higher during the first year (p < 0.0001). The infestation level by I. ricinus varied between grazing pastures and farms. Grazing pastu res in the vicinity of forest were more infested than the others, all through the study. The seasonal distribution of ticks showed peaks, wi th low fluctuations between farms, years and stages. Tick abundance co uld not be related to vegetation, but only to the vicinity of woods.