Tick Prevention Experiment Shows Promising Results

A three-year experiment in tick control in Mashomack Preserve on Shelter Island has shown encouraging results to combat these bothersome pests.

Researchers from Cornell University’s natural resources department studied and installed dozens of “four-poster” feeding stations that lure deer to a bin baited with corn, a favorite for deer, and rig the posting with rollers soaked with a tick–killing pesticide called permethrin—commonly found in shampoo for head lice. The system works when a deer rubs against the rollers, the deer’s skin comes in contact with the permethrin and the ticks die by the thousands.

The study hypothesized that one station can treat all the deer in about 100 acres.

New York had prohibited the use of “four-poster” devices in belief it would increase deer congregation, which perpetuates the risk of spreading chronic wasting disease-—a contagious neurological disease affecting deer, elk and moose. The study made it a priority to keep direct contact between wildlife to a minimum at the feeding station.

In 2005, the Department of Environmental Conservation approved the experiment for these confined areas, where Lyme infections were severe and chronic wasting disease unknown.

After three years of research, the “four-poster” baited deer stations were placed throughout Shelter Island in April 2008. The approval of this experiment marked a departure from the conservation department’s usual overcautious modus operandi, though the procedure received much resistance from hunters who were wary of the idea of permethrin in their venison.

However, Shelter Island residents were persistent in their claim about the out-of- control tick situation, and the project was finally approved.

Deer abundance and density, reproductive success, mortality rates, and deer trends were all carefully monitored within the treatment and control areas in the pre-study. Experts reassured skeptic hunters that the pesticide, permethrin, would remain only on the deer’s hair and skin, not in the muscle.

Thirty-nine deer were sampled for permethrin detections within their neck muscles between 2008 and 2010, six deer sampled positive. However, all deer tested negative for the pesticide in their hindquarter muscles and livers.

The outcome was excellent: Tick populations were reduced by more than 90%, according to Cornell’s study issued last year. Each individual year marked an incremental decrease in tick density.

Despite an unfavorable year for ticks in 2010, significant reductions were noted from levels in 2008.

Although the report only counts in passing numbers on the Southern Lone Star Tick, it cataloged a decline in that tick population on the small island. However, numbers of the Southern Lone Star tick remain high in Montauk, where they now outnumber the common deer tick.

Researchers were cautious about predicting a comparable drop in Lyme disease because so many factors are involved in its spread. But the experiment, which ended last year, seems well worth continuing and expanding to other parts of Long Island. This may be considered by the state’s conservation department.

There are over 16,000 cases of Lyme disease that occur each year in the United States. Unfortunately, the South Fork, due to its moist climate and proximity to the ocean, its populated landscape surrounded by ample marshlands or heavily wooded areas, is the supreme breeding ground for such nuisances.

The deer tick remains the primary cause of Lyme disease in the United States. The disease begins with a distinctive rash and flulike symptoms, and, in some cases, can progress to a more serious disease with complications affecting other body organs.

Incidentally, the study did not document any significant correlation between deer-vehicle collisions and proximity of four-poster stations.