Submitted to: Journal of Medical Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/15/2008
Publication Date: 12/1/2008
Citation: Carroll, J.F., Pound, J.M., Miller, J.A., Kramer, M.H. 2008. Reduced interference by gray squirrels with 4-poster deer treatment bait stations by using timed-release bait. Journal of Medical Entomology. 33(2):325-332. Interpretive Summary: Blacklegged (deer) ticks and lone star ticks transmit the pathogens causing Lyme disease and human monocytic ehrlichiosis, respectively. White-tailed deer are the principal host of adults of both species of tick. and populations of both species can be greatly reduced by the use of the 4-poster deer self-treatment devices. Squirrels eat the corn bait used in the 4-posters in a way that creates excessive corn fragments and meal which predispose the devices to clog and reduces their effectiveness. In a field trial, we tested the concept that by restricting the flow of the corn bait into the device’s feeding troughs during the day when squirrels are active we could limit accumulation of corn fragments and meal in the troughs. A photo-controlled restriction mechanism retrofitted into each of ten 4-posters regulated corn flow for a field trial. Corn restriction during the day did not reduce the use of the 4-posters by deer based on total weekly corn consumption, videotape evidence and contact of deer with acaricide applicators. The quantities of corn present in troughs and corn fragments and meal in troughs when the restriction mechanisms were operating or off indicated that squirrel interference with the posters was substantially reduced. These findings are of interest to users and manufacturer of the 4-poster device and researchers seeking means of controlling blacklegged and lone star tick populations.
Technical Abstract: As white-tailed deer, Odocoileus virginianus (Zimmermann), feed on corn bait dispensed by ‘4-poster’ tick control devices, they rub against paint rollers impregnated with acaricide. Gray squirrels, Sciurus carolinensis Gmelin, also feed on the corn bait in the feeding troughs of ‘4-posters,’ but in doing so they leave copious residues of corn fragments and meal in the troughs that compromise the effectiveness of the devices. A battery-operated closure mechanism controlled by a photo sensor was developed to block the flow of corn into the feeding troughs during the day when squirrels are active. The effectiveness of the corn-restriction concept and technology was evaluated using two groups of restrictor-equipped ‘4-posters’ at a tick-infested site in Maryland. Corn-restrictors were operational on group of ‘4-posters’ and corn was continuously available on the other group. The operational status of the restrictors for each group was switched at 2-wk intervals. The corn-restriction mechanism and concept effectively eliminated squirrel-related problems with ‘4-poster’ operation. Partially eaten corn and meal did not accumulate in ‘4-poster’ feeding troughs. Deer usage, as evidenced by weekly corn consumption and deer contact with the acaricide-impregnated paint rollers, was not significantly diminished.