INCREASE IN ABUNDANCE OF IMMATURE IXODES-SCAPULARIS (ACARI, IXODIDAE)IN AN EMERGENT LYME-DISEASE ENDEMIC AREA

Changes in tile abundance of immature Ixodes scapularis Say, the prima ry vector of Lyme disease, were assessed over a 7-yr period in Westche ster County, New York, where the disease is endemic. In total, 4,000 m (2) were drag sampled at each of 6 study sites in June and July of 198 4 and 1991. The abundance of nymphs collected from all sites was 2.6-f old greater in 1991 than in 1984. Four of the 6 sites had significantl y more nymphs in 1991, with increases ranging from 1.1- to 46.5-fold. The abundance of larvae collected from all sites was 34.2-fold higher in 1991 than in 1984. Five of the sites sampled had significantly more larvae in 1991, with increases ranging from 2.7- to 681-fold. These d ata demonstrate that populations of immature I. scapularis in Westches ter County have, overall, increased during the 7-yr period from 1984 t o 1991. However, the magnitude of increase is not uniform from site to site.