Efficacy of Amitraz Applied to White-Tailed Deer by the ‘4-Poster’ Topical Treatment Device in Controlling Free-Living Lone Star Ticks (Acari: Ixodidae)

Abstract

White-tailed deer treated themselves with a commercial pour-on acaricide formulation containing 2% amitraz as they fed from an ARS-patented '4-poster' topical treatment device. Whole kernel corn attracted deer to a single device placed in each of two deer-fenced pastures. In the treatment pasture, the rollers of the treatment device were charged with the acaricide, whereas the rollers of the device in the other pasture remained untreated. Deer were allowed to use the '4-posters' during periods of tick activity beginning in early to midspring and lasting through late summer to early fall for three consecutive years. Pretreatment sampling of adults and nymphs with dry-ice traps and larval masses with flip cloths showed no significant differences in population indices between the two pastures; however, after the third year of treatment, control of nymphal and adult ticks in the treated pasture was 91.9 and 93.7%, respectively, when compared with the untreated pasture. Control of larval masses increased from 68.4% in year 1 to 96.4% in year 2, but declined to 88.0% in year 3, probably because of the presence of feral hogs. This study demonstrated that application of amitraz to white-tailed deer through free-choice interaction with a '4-poster' device significantly reduced the abundance of free-living lone star ticks in a deer-fenced experimental pasture. Moreover, the yearly pattern of incremental increases in control and the final percentage control values for all three parasitic life stages in this topical application study were similar in magnitude to that observed in a previously conducted study in which the systemic acaricide ivermectin was used to reduce populations of free-living ticks by controlling ticks on deer.

Depletion Rates of Injected and Ingested Ivermectin from Blood Serum of Penned White-Tailed Deer, <I>Odocoileus virginianus</I> (Zimmermann) (Artiodactyla: Cervidae)

“…They demonstrated the importance of white-tailed deer as major hosts for maintenance of lone star tick populations, but more importantly, they determined that employing acaricides to control parasitic ticks feeding on white-tailed deer also could signiÞcantly reduce populations of free-living ticks in the treatment area. The concept was further substantiated in Þeld trials in which pesticide was applied topically to white-tailed deer that were attracted to and fed from the patented "4-poster" passive topical treatment device (Pound et al 1994(Pound et al , 2000a.…”

General introduction to areawide pest management.

“…In 1997 USDA-ARS implemented a 5-year wide area project against the blacklegged deer tick (Ixodes scapularis) in the north-east USA (Pound et at., 2000a;McGraw and McBride, 200 I). The project uses a device named the 'four-poster' as an alternative to eliminating deer populations or applying chemical sprays.…”

“…The technique is also used in Texas against lone star ticks (Amblyomma americanum) (Pound et at., 2000b;Flores, 2006). In 2003 scientists in Scotland began testing the '4-poster' topical applicator in that country (Flores, 2004b).…”

Prevention of arthropod-related disease

“…57 This type of strategy has proved effective in reducing tick numbers. 58,59 Ivermectin has also been added to feed corn to control tick populations. 60 Mouse bedding material impregnated with an acaricide can also be effective.…”