Submitted to: Vector-Borne and Zoonotic Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/27/2009
Publication Date: 10/30/2009
Citation: Carroll, J.F., Hill, D.E., Allen, P., Young, K.W., Kramer, M.H., Miramontes, E.N., Pound, J.M., Miller, J.A., George, J.E. 2009. The impact of '4-poster' deer self-treatment devices at three locations in Maryland. Vector-Borne and Zoonotic Diseases. 94(4):407-4116. Interpretive Summary: The blacklegged tick, Ixodes scapularis, is the principal vector of the pathogen causing Lyme disease, a serious human health problem in large areas of the U. S. Most adult I. scapularis feed on white-tailed deer. A device, the 4-poster, developed by ARS researchers at Kerrville, TX, passively applies insecticide to deer as they feed on corn bait. These devices were evaluated for their efficacy in reducing populations of I. scapularis and the lone star tick, Amblyomma americanum, in Maryland as part of USDA Northeast Tick Control Project. In 2002, after four years of treatment, 69-80% control of host-seeking I. scapularis nymphs was achieved at three 2 square mile sites in Maryland. Greater than 95% control of A. americanum was obtained at the two Maryland sites where this species occurred. In 2003, the first post-treatment year, tick numbers changed little from the previous year, but increased slightly in 2004. These results are of interest to scientists investigating technologies to control ticks, to the Department of Defense and municipalities and communities wishing to reduce tick populations.
Technical Abstract: From 1998-2002, 25 deer self-treatment devices (4-posters) using 2% amitraz, were operated at three locations in Maryland to determine their effectiveness in controlling blacklegged ticks, Ixodes scapularis Say, and lone star ticks, Amblyomma americanum (L.). Each treatment site was more or less 518 ha and paired with a similar site lacking '4-posters.' Locations varied in deer density, tick abundance, and land use. Flagging for host-seeking ticks, showed declines in tick populations at all treatment sites compared to control sites by the third year. By 2002, control of I. scapularis nymphs attributable to the '4-poster' intervention at the three sites was 69.0, 75.8 and 80%. Control of A. americanum numphs, at the two sites where they occurred, was 99.5 and 95.3%. In 2003, the first post-treatment year, control of I. scapularis remained around 2001-2002 levels, but by 2004, an upward trend in nymphal numbers was detectable. Populations of A. americanum showed no increase post-treatment. These results demonstrate that control of these tick species is locally possible with '4-poster' intervention.