Efficacy of amitraz-impregnated collars on white-tailed deer (Artiodactyla: Cervidae) in reducing free-living populations of lone star ticks (Acari: Ixodidae)

Authors: Pound, Joe; Lohmeyer, Kimberly - Kim; Davey, Ronald; MILLER, J - Retired ARS Employee; GEORGE, JOHN - Retired ARS Employee

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/7/2012
Publication Date: 12/17/2012
Citation: Pound, J.M., Lohmeyer, K.H., Davey, R.B., Miller, J.A., George, J.E. 2012. Efficacy of amitraz-impregnated collars on white-tailed deer (Artiodactyla: Cervidae) in reducing free-living populations of lone star ticks (Acari: Ixodidae). Journal of Economic Entomology. 105(6):2207-2212.

Interpretive Summary: Both species of cattle fever ticks that are the sole vectors of the agents causing potentially fatal Texas fever or bovine piroplasmosis in cattle were declared eradicated from the U.S. after a well-coordinated nationwide campaign lasting from 1907 to 1943. At that time, eradication was possible to a large extent because of minimal to essentially non-existent populations of white-tailed deer that otherwise would have acted as alternate hosts for the ticks and which could not have been gathered and treated as were cattle. The campaign to prevent ticks from being reintroduced across the border from Mexico continues today, but increasing populations of white-tailed deer are compromising the eradication effort by acting as viable alternative hosts that maintain infestations and disperse the ticks among multiple pastures. Currently, two self-treatment methods developed by ARS are being used to help control the ticks on deer that are quite efficacious, but they require that deer have constant daily access to whole kernel corn used as bait and thus are very expensive to deploy and maintain. This study evaluated the efficacy of acaricide impregnated collars that are attached around the necks of deer to control ticks feeding on them. As a result, the study demonstrated a similar degree of efficacy against free-living ticks in the plots with the treated deer as was obtained in similar studies with the initial two technologies. While collars in this study were manually applied to individually anesthetized or captured deer, the study provides proof of concept for use of acaricidal collars to control ticks on deer and consequently demonstrates feasibility for greater efficacy and a more economic treatment technology being realized from use of an ARS-patented automatic deer collar attachment/detachment device that is currently in final stages of development by ARS scientists.

Technical Abstract: Over a seven year period, we monitored the effect of a commercially available, amitraz impregnated anti-tick collar in controlling free-living populations of lone star ticks, Amblyomma americanum (L.) when manually fitted around necks of white-tailed deer, Odocoileus virginianus (Zimmermann). Study animals in treatment and control groups were confined in a 38.8 ha deer-fenced and densely vegetated treatment plot in South Texas. Tick densities during years one and seven served as untreated pre- and post-treatment comparisons and treatments occurred during years two through five. Reductions in tick densities in the treatment plot were compared against tick densities in a control plot having similar vegetation and numbers of untreated deer. During years of treatment, indices of control pressure ranged from 18.2 to 82.6 for nymphs and 16.9 to 78.7 for adults, and efficacy, expressed as percentage control during the final year of treatment, was 77.2 and 85.0%, respectively, for nymphal and adult ticks. These data show that acaricidal collar treatments provide efficacies very similar to those achieved with the existing ivermectin-medicated bait and ‘4-Poster’ topical treatment technologies to control ticks feeding on wild white-tailed deer.